Hi Thijs,
On Wed, Apr 10, 2024 at 11:11:41PM +0200 Thijs Raymakers wrote:
> Signed-off-by: Thijs Raymakers <thijs@xxxxxxxxxxxx>
You took me out throughout. I'm not sure that was needed :)
The new version looks fine. I'm not responsible for merging so if
Karel prefers the new arguments that works for me.
I'll update and test it out tomorrow. But I think you can put me back
if that works for you.
Cheers,
Phil
> ---
>
> Hi Karel,
>
> Thanks for the review!
>
> Op 09-04-2024 om 3:44 p.m. schreef Karel Zak:
> > I find it a little confusing that the --pid is sometimes used as a
> > source and in other cases as a destination.
> >
> > coresched --new --pid 123 # pid is destination
> > coresched --copy --pid 123 --dest 456 # pid is source
> >
> > It seems --copy always requires a source PID (according to the man
> > page), why not require a PID as argument for --copy:
> >
> > coresched --copy 123 --pid 456
> >
> > in this way --pid will be always destination (for 'copy' and 'new'
> > functions) and you will not need extra --dest option at all.
> >
> > If you want to keep the basic functions (e.g. --copy) without
> > arguments, it would be better to have --source, --dest, and
> > --dest-type instead of using the ambiguous --pid.
> >
> > I can also imagine the basic "functions" without "--".
> >
> > coresched [get] [--dest] 123
> > coresched copy [--source] 123 [--dest] 456
> > coresched new [--dest] 456
> >
> > In my opinion, we do not have to strictly adhere to old taskset or
> > similar commands.
>
> The command line arguments are currently somewhat similar in meaning
> to the arguments of taskset, which Phil mentioned he preferred.
> taskset (and others) uses --pid to refer to the PID. This works
> fine if you operate on just a single PID.
>
> I agree that this version of coresched can be indeed confusing to
> use if --pid is overloaded to mean both "source" and
> "destination", depending on the context. coresched needs at most two
> PIDs and can thus not use --pid for everything.
>
> How those two options are called/used seems to be a tradeoff between
> the familiarity by taskset users vs consistency within coreset.
> Either you use --pid which is familiar to users because other programs
> define PIDs like that, but the semantics will be inconsistent and will
> change depending what function of coresched you use.
> Or you use --source and --dest, which is a bit more inconvenient to
> use because you cannot use the same option to refer to a PID across the
> different coresed functions, but you will have consistent behavior of
> each option.
>
> Since you mention that we don't strictly have to adhere to taskset, I
> do have a slight preference for --source/--dest instead of --pid/--dest.
> With the help of the usage and/or man page, this difference shouldn't be
> too cumbersome to users that are familiar with other tools. The benefit
> of internal consistency outweights the benefit of familiarity in my
> opinion.
>
> Version 7 of the patch changes the arguments from --pid/--dest/--type
> (-t/-d/-t) to --source/--dest/--dest-type (-s/-d/-t). It also has the
> functions without the "--", as well as the other suggestions that you
> made. I've also added two more tests.
>
> The commands now look something like this
>
> coresched [get] [--source <PID>]
> coresched new [-t <TYPE>] --dest <PID>
> coresched new [-t <TYPE>] -- PROGRAM [ARGS...]
> coresched copy [--source <PID>] [-t <TYPE>] --dest <PID>
> coresched copy [--source <PID>] [-t <TYPE>] -- PROGRAM [ARGS...]
>
> > It should be noted that command line arguments are crucial, as they
> > are difficult to modify after release.
>
> It is good that you mentioned that the arguments felt confusing to use,
> because that is something that became a bit invisible to me after using
> the util for some time. It is important to get the arguments right, and
> making sure that they are sensible and self-consistent. These new
> command line arguments work for me as well. Phil previously expressed a
> preference for the --pid style so would like to know what his opinion is.
>
> > pedantic note, use extra space within ifdef
> >
> > #ifndef PR_SCHED_CORE
> > # define PR_SCHED_CORE 62
> > #endif
>
> I've changed to
>
> #ifndef PR_SCHED_CORE
> #define PR_SCHED_CORE 62
> #endif
>
> which looks a bit nicer in my opinion than what clang-format does with
> the AfterHash option. (I've used IndentPPDirectives: BeforeHash instead
> of IndentPPDirectives: None, which is the default in the kernel
> clang-format file)
>
>
> CC: Phil Auld and Thomas Weißschuh
> I've removed your Signed-off-by/Reviewed-by tags since this version
> differs significantly from the version that you've previously reviewed.
> I did't want to just assume that you approve of this version as well.
> With your permission, I can add the tags back again.
>
>
> Thijs
>
> Interdiff against v6:
> diff --git a/schedutils/coresched.1.adoc b/schedutils/coresched.1.adoc
> index c83fcdf91..00f2603e0 100644
> --- a/schedutils/coresched.1.adoc
> +++ b/schedutils/coresched.1.adoc
> @@ -17,9 +17,15 @@ coresched - manage core scheduling cookies for tasks
>
> == SYNOPSIS
>
> -*{command}* [options] *-p* _pid_
> +*{command}* [*get*] [*-s* _pid_]
>
> -*{command}* [options] \-- _command_ [_argument_...]
> +*{command}* *new* [*-t* _type_] *-d* _pid_
> +
> +*{command}* *new* [*-t* _type_] \-- _command_ [_argument_...]
> +
> +*{command}* *copy* [*-s* _pid_] [*-t* _type_] *-d* _pid_
> +
> +*{command}* *copy* [*-s* _pid_] [*-t* _type_] \-- _command_ [_argument_...]
>
> == DESCRIPTION
> The *{command}* command is used to retrieve or modify the core scheduling cookies of a running process given its _pid_, or to spawn a new _command_ with core scheduling cookies.
> @@ -31,22 +37,28 @@ Only tasks have the same cookie are allowed to be scheduled on the same physical
> It is possible to either assign a new random cookie to a task, or copy a cookie from another task. It is not possible to choose the value of the cookie.
>
> == FUNCTIONS
> -*-n*, *--new*::
> -Assign a new cookie to an existing PID or to execute _command_ with a new cookie.
> +*get*::
> +Retrieve the core scheduling cookie of the PID specified in *-s*.
> +If *-s* is omitted, it will get the cookie of the current *{command}* process.
>
> -*-c*, *--copy*::
> -Copy the cookie from an existing PID to another PID, or execute _command_ with that copied cookie.
> +*new*::
> +Assign a new cookie to an existing PID specified in *-d*, or execute _command_ with a new cookie.
>
> -If no function is specified, it will print the cookie of the current task, or of the task specified with the *-p* option.
> +*copy*::
> +Copy the cookie from an existing PID (*-s*) to another PID (*-d*), or execute _command_ with that cookie.
> +If *-s* is omitted, it will get the cookie of the current *{command}* process.
> +
> +If no function is specified, it will run the *get* function.
>
> == OPTIONS
> -*-p*, *--pid* _PID_::
> -Operate on an existing PID and do not launch a new task.
> +*-s*, *--source* _PID_::
> +Which _PID_ to get the cookie from.
> +If this option is omitted, it will get the cookie from the current *{command}* process.
>
> *-d*, *--dest* _PID_::
> -When using *--copy*, specify a destination PID where you want to copy the cookie to.
> +Which _PID_ to modify the cookie of.
>
> -*-t*, *--type* _TYPE_::
> +*-t*, *--dest-type* _TYPE_::
> The type of the PID whose cookie will be modified. This can be one of three values:
> - *pid*, or process ID
> - *tgid*, or thread group ID (default value)
> @@ -63,25 +75,28 @@ Print version and exit.
>
> == EXAMPLES
> Get the core scheduling cookie of the {command} task itself, usually inherited from its parent{colon}::
> -*{command}*
> +*{command} get*
>
> Get the core scheduling cookie of a task with PID _123_{colon}::
> -*{command} -p* _123_
> +*{command} get -s* _123_
>
> Give a task with PID _123_ a new core scheduling cookie{colon}::
> -*{command} --new -p* _123_
> +*{command} new -d* _123_
>
> Spawn a new task with a new core scheduling cookie{colon}::
> -*{command} --new* \-- _command_ [_argument_...]
> +*{command} new* \-- _command_ [_argument_...]
> +
> +Copy the cookie from the current {command} process another task with pid _456_{colon}::
> +*{command} copy -d* _456_
>
> Copy the cookie from a task with pid _123_ to another task with pid _456_{colon}::
> -*{command} --copy -p* _123_ *-d* _456_
> +*{command} copy -s* _123_ *-d* _456_
>
> Copy the cookie from a task with pid _123_ to a new task _command_{colon}::
> -*{command} --copy -p* _123_ \-- _command_ [_argument_...]
> +*{command} copy -s* _123_ \-- _command_ [_argument_...]
>
> Copy the cookie from a task with pid _123_ to the process group ID _456_{colon}::
> -*{command} --copy -p* _123_ *-t* pgid *-d* _456_
> +*{command} copy -s* _123_ *-t* _pgid_ *-d* _456_
>
> == PERMISSIONS
> When retrieving or modifying the core scheduling cookie of a process, you need to have *PTRACE_MODE_READ_REALCREDS* ptrace access to that process.
> @@ -98,12 +113,11 @@ If a _command_ is being executed, the return value of *{command}* will be the re
> This can be enabled via the *CONFIG_SCHED_CORE* kernel config option.
>
> == AUTHORS
> -mailto:thijs@xxxxxxxxxxxx[Thijs Raymakers],
> -mailto:pauld@xxxxxxxxxx[Phil Auld]
> +mailto:thijs@xxxxxxxxxxxx[Thijs Raymakers]
>
> == COPYRIGHT
>
> -Copyright {copyright} 2024 Thijs Raymakers and Phil Auld. This is free software licensed under the EUPL.
> +Copyright {copyright} 2024 Thijs Raymakers. This is free software licensed under the EUPL.
>
> == SEE ALSO
> *chrt*(1),
> diff --git a/schedutils/coresched.c b/schedutils/coresched.c
> index b6be1717d..7e3cc46d2 100644
> --- a/schedutils/coresched.c
> +++ b/schedutils/coresched.c
> @@ -3,7 +3,7 @@
> *
> * coresched.c - manage core scheduling cookies for tasks
> *
> - * Copyright (C) 2024 Thijs Raymakers, Phil Auld
> + * Copyright (C) 2024 Thijs Raymakers
> * Licensed under the EUPL v1.2
> */
>
> @@ -16,34 +16,33 @@
> #include "c.h"
> #include "closestream.h"
> #include "nls.h"
> -#include "optutils.h"
> #include "strutils.h"
>
> // These definitions might not be defined in the header files, even if the
> // prctl interface in the kernel accepts them as valid.
> #ifndef PR_SCHED_CORE
> -#define PR_SCHED_CORE 62
> + #define PR_SCHED_CORE 62
> #endif
> #ifndef PR_SCHED_CORE_GET
> -#define PR_SCHED_CORE_GET 0
> + #define PR_SCHED_CORE_GET 0
> #endif
> #ifndef PR_SCHED_CORE_CREATE
> -#define PR_SCHED_CORE_CREATE 1
> + #define PR_SCHED_CORE_CREATE 1
> #endif
> #ifndef PR_SCHED_CORE_SHARE_TO
> -#define PR_SCHED_CORE_SHARE_TO 2
> + #define PR_SCHED_CORE_SHARE_TO 2
> #endif
> #ifndef PR_SCHED_CORE_SHARE_FROM
> -#define PR_SCHED_CORE_SHARE_FROM 3
> + #define PR_SCHED_CORE_SHARE_FROM 3
> #endif
> #ifndef PR_SCHED_CORE_SCOPE_THREAD
> -#define PR_SCHED_CORE_SCOPE_THREAD 0
> + #define PR_SCHED_CORE_SCOPE_THREAD 0
> #endif
> #ifndef PR_SCHED_CORE_SCOPE_THREAD_GROUP
> -#define PR_SCHED_CORE_SCOPE_THREAD_GROUP 1
> + #define PR_SCHED_CORE_SCOPE_THREAD_GROUP 1
> #endif
> #ifndef PR_SCHED_CORE_SCOPE_PROCESS_GROUP
> -#define PR_SCHED_CORE_SCOPE_PROCESS_GROUP 2
> + #define PR_SCHED_CORE_SCOPE_PROCESS_GROUP 2
> #endif
>
> typedef int sched_core_scope;
> @@ -55,7 +54,7 @@ typedef enum {
> } sched_core_cmd;
>
> struct args {
> - pid_t pid;
> + pid_t src;
> pid_t dest;
> sched_core_scope type;
> sched_core_cmd cmd;
> @@ -67,40 +66,44 @@ static bool sched_core_verbose = false;
> static void __attribute__((__noreturn__)) usage(void)
> {
> fputs(USAGE_HEADER, stdout);
> - fprintf(stdout, _(" %s [-p PID]\n"), program_invocation_short_name);
> - fprintf(stdout, _(" %s --new [-t <TYPE>] -p <PID>\n"),
> + fprintf(stdout, _(" %s [get] [--source <PID>]\n"),
> program_invocation_short_name);
> - fprintf(stdout, _(" %s --new [-t <TYPE>] -- PROGRAM [ARGS...]\n"),
> + fprintf(stdout, _(" %s new [-t <TYPE>] --dest <PID>\n"),
> program_invocation_short_name);
> - fprintf(stdout, _(" %s --copy -p <PID> [-t <TYPE>] -d <PID>\n"),
> + fprintf(stdout, _(" %s new [-t <TYPE>] -- PROGRAM [ARGS...]\n"),
> program_invocation_short_name);
> fprintf(stdout,
> - _(" %s --copy -p <PID> [-t <TYPE>] -- PROGRAM [ARGS...]\n"),
> + _(" %s copy [--source <PID>] [-t <TYPE>] --dest <PID>\n"),
> + program_invocation_short_name);
> + fprintf(stdout,
> + _(" %s copy [--source <PID>] [-t <TYPE>] -- PROGRAM [ARGS...]\n"),
> program_invocation_short_name);
>
> fputs(USAGE_SEPARATOR, stdout);
> fputsln(_("Manage core scheduling cookies for tasks."), stdout);
>
> fputs(USAGE_FUNCTIONS, stdout);
> - fputsln(_(" -n, --new assign a new core scheduling cookie to an existing PID or\n"
> - " execute a program with a new cookie."),
> + fputsln(_(" get retrieve the core scheduling cookie of a PID"),
> stdout);
> - fputsln(_(" -c, --copy copy the core scheduling cookie from an existing PID to\n"
> - " either another PID, or copy it to a new program"),
> + fputsln(_(" new assign a new core scheduling cookie to an existing\n"
> + " PID or execute a program with a new cookie"),
> stdout);
> - fputsln(_("\n If no function is provided, it will retrieve and print the cookie from\n"
> - " the PID provided via --pid.\n"),
> + fputsln(_(" copy copy the core scheduling cookie from an existing PID\n"
> + " to another PID, or execute a program with that\n"
> + " copied cookie"),
> stdout);
>
> fputs(USAGE_OPTIONS, stdout);
> - fputsln(_(" -p, --pid <PID> operate on an existing PID"), stdout);
> - fputsln(_(" -d, --dest <PID> when copying a cookie from an existing PID, --dest is\n"
> - " the destination PID where to copy the cookie to."),
> + fprintf(stdout,
> + _(" -s, --source <PID> which PID to get the cookie from\n"
> + " If omitted, it is the PID of %s itself\n"),
> + program_invocation_short_name);
> + fputsln(_(" -d, --dest <PID> which PID to modify the cookie of\n"),
> stdout);
> - fputsln(_(" -t, --type <TYPE> type of the destination PID, or the type of the PID\n"
> - " when a new core scheduling cookie is created.\n"
> - " Can be one of the following: pid, tgid or pgid.\n"
> - " The default is tgid."),
> + fputsln(_(" -t, --dest-type <TYPE> type of the destination PID, or the type of the PID\n"
> + " when a new core scheduling cookie is created.\n"
> + " Can be one of the following: pid, tgid or pgid.\n"
> + " The default is tgid."),
> stdout);
> fputs(USAGE_SEPARATOR, stdout);
> fputsln(_(" -v, --verbose verbose"), stdout);
> @@ -151,9 +154,8 @@ static void core_sched_copy_cookie(pid_t from, pid_t to,
>
> if (sched_core_verbose) {
> sched_core_cookie before = core_sched_get_cookie(from);
> - fprintf(stderr,
> - _("%s: copied cookie 0x%lx from PID %d to PID %d\n"),
> - program_invocation_short_name, before, from, to);
> + warnx(_("copied cookie 0x%lx from PID %d to PID %d"), before,
> + from, to);
> }
> }
>
> @@ -161,25 +163,21 @@ static void core_sched_get_and_print_cookie(pid_t pid)
> {
> if (sched_core_verbose) {
> sched_core_cookie after = core_sched_get_cookie(pid);
> - fprintf(stderr, _("%s: set cookie of PID %d to 0x%lx\n"),
> - program_invocation_short_name, pid, after);
> + warnx(_("set cookie of PID %d to 0x%lx"), pid, after);
> }
> }
>
> static void core_sched_exec_with_cookie(struct args *args, char **argv)
> {
> - if (!args->exec_argv_offset)
> - usage();
> -
> // Move the argument list to the first argument of the program
> argv = &argv[args->exec_argv_offset];
>
> // If a source PID is provided, try to copy the cookie from
> // that PID. Otherwise, create a brand new cookie with the
> // provided type.
> - if (args->pid) {
> - core_sched_pull_cookie(args->pid);
> - core_sched_get_and_print_cookie(args->pid);
> + if (args->src) {
> + core_sched_pull_cookie(args->src);
> + core_sched_get_and_print_cookie(args->src);
> } else {
> pid_t pid = getpid();
> core_sched_create_cookie(pid, args->type);
> @@ -218,42 +216,26 @@ static sched_core_scope parse_core_sched_type(char *str)
> str);
> }
>
> -static void parse_arguments(int argc, char **argv, struct args *args)
> +static void parse_and_verify_arguments(int argc, char **argv, struct args *args)
> {
> int c;
>
> static const struct option longopts[] = {
> - { "new", no_argument, NULL, 'n' },
> - { "copy", no_argument, NULL, 'c' },
> - { "pid", required_argument, NULL, 'p' },
> + { "source", required_argument, NULL, 's' },
> { "dest", required_argument, NULL, 'd' },
> - { "type", required_argument, NULL, 't' },
> + { "dest-type", required_argument, NULL, 't' },
> { "verbose", no_argument, NULL, 'v' },
> { "version", no_argument, NULL, 'V' },
> { "help", no_argument, NULL, 'h' },
> { NULL, 0, NULL, 0 }
> };
> - static const ul_excl_t excl[] = {
> - { 'c', 'n' }, // Cannot do both --new and --copy
> - { 'd', 'n' }, // Cannot have both --new and --dest
> - { 0 }
> - };
> -
> - int excl_st[ARRAY_SIZE(excl)] = UL_EXCL_STATUS_INIT;
>
> - while ((c = getopt_long(argc, argv, "ncp:d:t:vVh", longopts, NULL)) !=
> - -1) {
> - err_exclusive_options(c, longopts, excl, excl_st);
> + while ((c = getopt_long(argc, argv, "s:d:t:vVh", longopts, NULL)) != -1)
> switch (c) {
> - case 'n':
> - args->cmd = SCHED_CORE_CMD_NEW;
> - break;
> - case 'c':
> - args->cmd = SCHED_CORE_CMD_COPY;
> - break;
> - case 'p':
> - args->pid = strtopid_or_err(
> - optarg, _("Failed to parse PID for -p/--pid"));
> + case 's':
> + args->src = strtopid_or_err(
> + optarg,
> + _("Failed to parse PID for -s/--source"));
> break;
> case 'd':
> args->dest = strtopid_or_err(
> @@ -272,58 +254,77 @@ static void parse_arguments(int argc, char **argv, struct args *args)
> default:
> errtryhelp(EXIT_FAILURE);
> }
> +
> + if (argc <= optind) {
> + args->cmd = SCHED_CORE_CMD_GET;
> + } else {
> + if (!strcmp(argv[optind], "get"))
> + args->cmd = SCHED_CORE_CMD_GET;
> + else if (!strcmp(argv[optind], "new"))
> + args->cmd = SCHED_CORE_CMD_NEW;
> + else if (!strcmp(argv[optind], "copy"))
> + args->cmd = SCHED_CORE_CMD_COPY;
> + else
> + bad_usage(_("Unknown function"));
> +
> + // Since we parsed an extra "option" outside of getopt_long, we have to
> + // increment optind manually.
> + ++optind;
> }
>
> - if (args->cmd == SCHED_CORE_CMD_COPY && !args->pid)
> - bad_usage(_("--copy: requires a -p/--pid"));
> + if (args->cmd == SCHED_CORE_CMD_GET && args->dest)
> + bad_usage(_("get does not accept the --dest option"));
> +
> + if (args->cmd == SCHED_CORE_CMD_NEW && args->src)
> + bad_usage(_("new does not accept the --source option"));
> +
> + // If the -s/--source option is not specified, it defaults to the PID
> + // of the current coresched process
> + if (args->cmd != SCHED_CORE_CMD_NEW && !args->src)
> + args->src = getpid();
>
> // More arguments have been passed, which means that the user wants to run
> // another program with a core scheduling cookie.
> if (argc > optind) {
> switch (args->cmd) {
> case SCHED_CORE_CMD_GET:
> - bad_usage(_("Unknown command"));
> + bad_usage(_("bad usage of the get function"));
> break;
> case SCHED_CORE_CMD_NEW:
> - if (args->pid)
> + if (args->dest)
> bad_usage(_(
> - "--new: cannot accept both a -p/--pid and a command"));
> + "new requires either a -d/--dest or a command"));
> else
> args->exec_argv_offset = optind;
> break;
> case SCHED_CORE_CMD_COPY:
> if (args->dest)
> bad_usage(_(
> - "--copy: cannot accept both a destination PID "
> - "-d/--dest and a command"));
> + "copy requires either a -d/--dest or a command"));
> else
> args->exec_argv_offset = optind;
> break;
> }
> - }
> -
> - if (argc <= optind) {
> - if (args->cmd == SCHED_CORE_CMD_NEW && !args->pid)
> + } else {
> + if (args->cmd == SCHED_CORE_CMD_NEW && !args->dest)
> bad_usage(_(
> - "--new: requires either a -p/--pid or a command"));
> + "new requires either a -d/--dest or a command"));
> if (args->cmd == SCHED_CORE_CMD_COPY && !args->dest)
> bad_usage(_(
> - "--copy: requires either a -d/--dest or a command"));
> + "copy requires either a -d/--dest or a command"));
> }
> }
>
> int main(int argc, char **argv)
> {
> - struct args args = { 0 };
> - args.cmd = SCHED_CORE_CMD_GET;
> - args.type = PR_SCHED_CORE_SCOPE_THREAD_GROUP;
> + struct args args = { .type = PR_SCHED_CORE_SCOPE_THREAD_GROUP };
>
> setlocale(LC_ALL, "");
> bindtextdomain(PACKAGE, LOCALEDIR);
> textdomain(PACKAGE);
> close_stdout_atexit();
>
> - parse_arguments(argc, argv, &args);
> + parse_and_verify_arguments(argc, argv, &args);
>
> if (!is_core_sched_supported())
> errx(EXIT_FAILURE,
> @@ -331,27 +332,25 @@ int main(int argc, char **argv)
> "support CONFIG_SCHED_CORE?"));
>
> sched_core_cookie cookie;
> - pid_t pid;
>
> switch (args.cmd) {
> case SCHED_CORE_CMD_GET:
> - pid = args.pid ? args.pid : getpid();
> - cookie = core_sched_get_cookie(pid);
> - printf(_("cookie of pid %d is 0x%lx\n"), pid, cookie);
> + cookie = core_sched_get_cookie(args.src);
> + printf(_("cookie of pid %d is 0x%lx\n"), args.src, cookie);
> break;
> case SCHED_CORE_CMD_NEW:
> - if (args.pid) {
> - core_sched_create_cookie(args.pid, args.type);
> - core_sched_get_and_print_cookie(args.pid);
> - } else {
> + if (args.exec_argv_offset) {
> core_sched_exec_with_cookie(&args, argv);
> + } else {
> + core_sched_create_cookie(args.dest, args.type);
> + core_sched_get_and_print_cookie(args.dest);
> }
> break;
> case SCHED_CORE_CMD_COPY:
> - if (args.dest)
> - core_sched_copy_cookie(args.pid, args.dest, args.type);
> - else
> + if (args.exec_argv_offset)
> core_sched_exec_with_cookie(&args, argv);
> + else
> + core_sched_copy_cookie(args.src, args.dest, args.type);
> break;
> default:
> usage();
> diff --git a/tests/expected/schedutils/coresched-change-cookie-of-parent b/tests/expected/schedutils/coresched-change-cookie-of-parent
> deleted file mode 100644
> index d08118c02..000000000
> --- a/tests/expected/schedutils/coresched-change-cookie-of-parent
> +++ /dev/null
> @@ -1 +0,0 @@
> -cookie of pid OWN_PID is DIFFERENT_COOKIE
> diff --git a/tests/expected/schedutils/coresched-spawn-child-with-new-cookie b/tests/expected/schedutils/coresched-copy-from-child-to-parent
> similarity index 100%
> rename from tests/expected/schedutils/coresched-spawn-child-with-new-cookie
> rename to tests/expected/schedutils/coresched-copy-from-child-to-parent
> diff --git a/tests/expected/schedutils/coresched-copy-from-parent-to-nested-child b/tests/expected/schedutils/coresched-copy-from-parent-to-nested-child
> new file mode 100644
> index 000000000..ecfc41142
> --- /dev/null
> +++ b/tests/expected/schedutils/coresched-copy-from-parent-to-nested-child
> @@ -0,0 +1 @@
> +SAME_COOKIE
> diff --git a/tests/expected/schedutils/coresched-get-cookie-own-pid b/tests/expected/schedutils/coresched-get-cookie-own-pid
> new file mode 100644
> index 000000000..84f182cbe
> --- /dev/null
> +++ b/tests/expected/schedutils/coresched-get-cookie-own-pid
> @@ -0,0 +1 @@
> +cookie of pid OWN_PID is PARENT_COOKIE
> diff --git a/tests/expected/schedutils/coresched-get-cookie-parent-pid b/tests/expected/schedutils/coresched-get-cookie-parent-pid
> new file mode 100644
> index 000000000..e183e0402
> --- /dev/null
> +++ b/tests/expected/schedutils/coresched-get-cookie-parent-pid
> @@ -0,0 +1 @@
> +cookie of pid PARENT_PID is PARENT_COOKIE
> diff --git a/tests/expected/schedutils/coresched-get-own-pid-with-cookie b/tests/expected/schedutils/coresched-get-own-pid-with-cookie
> deleted file mode 100644
> index 3d7f08040..000000000
> --- a/tests/expected/schedutils/coresched-get-own-pid-with-cookie
> +++ /dev/null
> @@ -1 +0,0 @@
> -cookie of pid OWN_PID is COOKIE
> diff --git a/tests/expected/schedutils/coresched-new-child-with-new-cookie b/tests/expected/schedutils/coresched-new-child-with-new-cookie
> new file mode 100644
> index 000000000..5b9c40052
> --- /dev/null
> +++ b/tests/expected/schedutils/coresched-new-child-with-new-cookie
> @@ -0,0 +1 @@
> +DIFFERENT_COOKIE
> diff --git a/tests/expected/schedutils/coresched-set-cookie-own-pid.err b/tests/expected/schedutils/coresched-set-cookie-own-pid.err
> deleted file mode 100644
> index 1816a4fbd..000000000
> --- a/tests/expected/schedutils/coresched-set-cookie-own-pid.err
> +++ /dev/null
> @@ -1 +0,0 @@
> -coresched: set cookie of PID OWN_PID to COOKIE
> diff --git a/tests/expected/schedutils/coresched-set-cookie-parent-pid.err b/tests/expected/schedutils/coresched-set-cookie-parent-pid.err
> new file mode 100644
> index 000000000..e7318ffc2
> --- /dev/null
> +++ b/tests/expected/schedutils/coresched-set-cookie-parent-pid.err
> @@ -0,0 +1 @@
> +coresched: set cookie of PID PARENT_PID to PARENT_COOKIE
> diff --git a/tests/expected/schedutils/set-cookie-parent-pid b/tests/expected/schedutils/set-cookie-parent-pid
> new file mode 100644
> index 000000000..e7318ffc2
> --- /dev/null
> +++ b/tests/expected/schedutils/set-cookie-parent-pid
> @@ -0,0 +1 @@
> +coresched: set cookie of PID PARENT_PID to PARENT_COOKIE
> diff --git a/tests/ts/schedutils/coresched b/tests/ts/schedutils/coresched
> index ed96d89de..e34fa319f 100755
> --- a/tests/ts/schedutils/coresched
> +++ b/tests/ts/schedutils/coresched
> @@ -13,8 +13,8 @@ TS_DESC="coresched"
> ts_init "$*"
>
> ts_check_test_command "$TS_CMD_CORESCHED"
> -ts_check_test_command "tee"
> -ts_check_test_command "sed"
> +ts_check_prog "tee"
> +ts_check_prog "sed"
>
> # If there is no kernel support, skip the test suite
> CORESCHED_TEST_KERNEL_SUPPORT_CMD=$($TS_CMD_CORESCHED 2>&1)
> @@ -30,33 +30,54 @@ fi
> # - Any other cookie is replaced by `DIFFERENT_COOKIE`
> # The behavior of coresched does not depend on the exact values of these cookies, so using
> # placeholder values does not change the behavior tests.
> -ts_init_subtest "set-cookie-own-pid"
> -CORESCHED_OUTPUT=$( ($TS_CMD_CORESCHED -v -n -p $$ | tee -a "$TS_OUTPUT") 3>&1 1>&2 2>&3 | sed "s/$$/OWN_PID/g")
> -CORESCHED_COOKIE=$(echo "$CORESCHED_OUTPUT" | sed 's/^.*\(0x.*$\)/\1/g')
> -if [ -z "$CORESCHED_COOKIE" ]; then
> - ts_failed "empty value for CORESCHED_COOKIE "
> +ts_init_subtest "set-cookie-parent-pid"
> +CORESCHED_OUTPUT=$( ($TS_CMD_CORESCHED -v new -d $$ \
> + | tee -a "$TS_OUTPUT") 3>&1 1>&2 2>&3 \
> + | sed "s/$$/PARENT_PID/g")
> +CORESCHED_PARENT_COOKIE=$(echo "$CORESCHED_OUTPUT" | sed 's/^.*\(0x.*$\)/\1/g')
> +if [ -z "$CORESCHED_PARENT_COOKIE" ]; then
> + ts_failed "empty value for CORESCHED_PARENT_COOKIE"
> fi
> -CORESCHED_OUTPUT=$(echo "$CORESCHED_OUTPUT" | sed "s/$CORESCHED_COOKIE/COOKIE/g")
> +CORESCHED_OUTPUT=$(echo "$CORESCHED_OUTPUT" \
> + | sed "s/$CORESCHED_PARENT_COOKIE/PARENT_COOKIE/g")
> echo "$CORESCHED_OUTPUT" >> "$TS_ERRLOG"
> ts_finalize_subtest
>
> -ts_init_subtest "get-own-pid-with-cookie"
> -$TS_CMD_CORESCHED -p $$ 2>> "$TS_ERRLOG" | sed "s/$$/OWN_PID/g" | sed "s/$CORESCHED_COOKIE/COOKIE/g" >> "$TS_OUTPUT"
> +ts_init_subtest "get-cookie-parent-pid"
> +$TS_CMD_CORESCHED get -s $$ 2>> "$TS_ERRLOG" \
> + | sed -e "s/$$/PARENT_PID/g" \
> + -e "s/$CORESCHED_PARENT_COOKIE/PARENT_COOKIE/g" >> "$TS_OUTPUT"
> ts_finalize_subtest
>
> -ts_init_subtest "spawn-child-with-new-cookie"
> -$TS_CMD_CORESCHED -n -- "$TS_CMD_CORESCHED" 2>> "$TS_ERRLOG" \
> - | sed 's/^.*\(0x.*$\)/\1/g' \
> - | sed "s/$CORESCHED_COOKIE/SAME_COOKIE/g" \
> - | sed "s/0x.*$/DIFFERENT_COOKIE/g" >> "$TS_OUTPUT"
> +ts_init_subtest "get-cookie-own-pid"
> +$TS_CMD_CORESCHED get 2>> "$TS_ERRLOG" \
> + | sed -e "s/pid [0-9]\+/pid OWN_PID/g" \
> + -e "s/$CORESCHED_PARENT_COOKIE/PARENT_COOKIE/g" >> "$TS_OUTPUT"
> ts_finalize_subtest
>
> -ts_init_subtest "change-cookie-of-parent"
> -$TS_CMD_CORESCHED -n -- /bin/bash -c "$TS_CMD_CORESCHED -c -p \$\$ -d $$"
> -$TS_CMD_CORESCHED -p $$ 2>> "$TS_ERRLOG" \
> - | sed "s/$$/OWN_PID/g" \
> - | sed "s/$CORESCHED_COOKIE/COOKIE/g" \
> - | sed "s/0x.*$/DIFFERENT_COOKIE/g" >> "$TS_OUTPUT"
> +ts_init_subtest "new-child-with-new-cookie"
> +$TS_CMD_CORESCHED new -- "$TS_CMD_CORESCHED" get 2>> "$TS_ERRLOG" \
> + | sed -e 's/^.*\(0x.*$\)/\1/g' \
> + -e "s/$CORESCHED_PARENT_COOKIE/SAME_COOKIE/g" \
> + -e "s/0x.*$/DIFFERENT_COOKIE/g" >> "$TS_OUTPUT"
> +ts_finalize_subtest
> +
> +ts_init_subtest "copy-from-parent-to-nested-child"
> +$TS_CMD_CORESCHED new -- /bin/bash -c \
> + "$TS_CMD_CORESCHED copy -s $$ -- $TS_CMD_CORESCHED get" \
> +2>> "$TS_ERRLOG" \
> + | sed -e 's/^.*\(0x.*$\)/\1/g' \
> + -e "s/$CORESCHED_PARENT_COOKIE/SAME_COOKIE/g" \
> + -e "s/0x.*$/DIFFERENT_COOKIE/g" >> "$TS_OUTPUT"
> +ts_finalize_subtest
> +
> +ts_init_subtest "copy-from-child-to-parent"
> +$TS_CMD_CORESCHED new -- /bin/bash -c \
> + "$TS_CMD_CORESCHED copy -s \$\$ -d $$"
> +$TS_CMD_CORESCHED get 2>> "$TS_ERRLOG" \
> + | sed -e 's/^.*\(0x.*$\)/\1/g' \
> + -e "s/$CORESCHED_PARENT_COOKIE/SAME_COOKIE/g" \
> + -e "s/0x.*$/DIFFERENT_COOKIE/g" >> "$TS_OUTPUT"
> ts_finalize_subtest
>
> ts_finalize
>
> .gitignore | 1 +
> bash-completion/coresched | 0
> configure.ac | 12 +-
> meson.build | 16 +-
> meson_options.txt | 2 +-
> schedutils/Makemodule.am | 8 +
> schedutils/coresched.1.adoc | 138 +++++++
> schedutils/coresched.c | 358 ++++++++++++++++++
> tests/commands.sh | 1 +
> .../coresched-copy-from-child-to-parent | 1 +
> ...coresched-copy-from-parent-to-nested-child | 1 +
> .../schedutils/coresched-get-cookie-own-pid | 1 +
> .../coresched-get-cookie-parent-pid | 1 +
> .../coresched-new-child-with-new-cookie | 1 +
> .../coresched-set-cookie-parent-pid.err | 1 +
> .../expected/schedutils/set-cookie-parent-pid | 1 +
> tests/ts/schedutils/coresched | 83 ++++
> 17 files changed, 620 insertions(+), 6 deletions(-)
> create mode 100644 bash-completion/coresched
> create mode 100644 schedutils/coresched.1.adoc
> create mode 100644 schedutils/coresched.c
> create mode 100644 tests/expected/schedutils/coresched-copy-from-child-to-parent
> create mode 100644 tests/expected/schedutils/coresched-copy-from-parent-to-nested-child
> create mode 100644 tests/expected/schedutils/coresched-get-cookie-own-pid
> create mode 100644 tests/expected/schedutils/coresched-get-cookie-parent-pid
> create mode 100644 tests/expected/schedutils/coresched-new-child-with-new-cookie
> create mode 100644 tests/expected/schedutils/coresched-set-cookie-parent-pid.err
> create mode 100644 tests/expected/schedutils/set-cookie-parent-pid
> create mode 100755 tests/ts/schedutils/coresched
>
> diff --git a/.gitignore b/.gitignore
> index 6ecbfa7fe..316f3cdcc 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -94,6 +94,7 @@ ylwrap
> /colcrt
> /colrm
> /column
> +/coresched
> /ctrlaltdel
> /delpart
> /dmesg
> diff --git a/bash-completion/coresched b/bash-completion/coresched
> new file mode 100644
> index 000000000..e69de29bb
> diff --git a/configure.ac b/configure.ac
> index ab7c98636..3a189a075 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -2500,9 +2500,9 @@ UL_REQUIRES_HAVE([setterm], [ncursesw, ncurses], [ncursesw or ncurses library])
> AM_CONDITIONAL([BUILD_SETTERM], [test "x$build_setterm" = xyes])
>
> # build_schedutils= is just configure-only variable to control
> -# ionice, taskset and chrt
> +# ionice, taskset, coresched and chrt
> AC_ARG_ENABLE([schedutils],
> - AS_HELP_STRING([--disable-schedutils], [do not build chrt, ionice, taskset]),
> + AS_HELP_STRING([--disable-schedutils], [do not build chrt, ionice, taskset, coresched]),
> [], [UL_DEFAULT_ENABLE([schedutils], [check])]
> )
>
> @@ -2545,6 +2545,14 @@ UL_REQUIRES_SYSCALL_CHECK([taskset],
> AM_CONDITIONAL([BUILD_TASKSET], [test "x$build_taskset" = xyes])
>
>
> +UL_ENABLE_ALIAS([coresched], [schedutils])
> +UL_BUILD_INIT([coresched])
> +UL_REQUIRES_SYSCALL_CHECK([coresched],
> + [UL_CHECK_SYSCALL([prctl])],
> + [prctl])
> +AM_CONDITIONAL([BUILD_CORESCHED], [test "x$build_coresched" = xyes])
> +
> +
> have_schedsetter=no
> AS_IF([test "x$ac_cv_func_sched_setscheduler" = xyes], [have_schedsetter=yes],
> [test "x$ac_cv_func_sched_setattr" = xyes], [have_schedsetter=yes])
> diff --git a/meson.build b/meson.build
> index 9600ce49f..a3a648753 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -3111,13 +3111,23 @@ exe4 = executable(
> install : opt,
> build_by_default : opt)
>
> +exe5 = executable(
> + 'coresched',
> + 'schedutils/coresched.c',
> + include_directories : includes,
> + link_with : lib_common,
> + install_dir : usrbin_exec_dir,
> + install : opt,
> + build_by_default : opt)
> +
> if opt and not is_disabler(exe)
> - exes += [exe, exe2, exe3, exe4]
> + exes += [exe, exe2, exe3, exe4, exe5]
> manadocs += ['schedutils/chrt.1.adoc',
> 'schedutils/ionice.1.adoc',
> 'schedutils/taskset.1.adoc',
> - 'schedutils/uclampset.1.adoc']
> - bashcompletions += ['chrt', 'ionice', 'taskset', 'uclampset']
> + 'schedutils/uclampset.1.adoc',
> + 'schedutils/coresched.1.adoc']
> + bashcompletions += ['chrt', 'ionice', 'taskset', 'uclampset', 'coresched']
> endif
>
> ############################################################
> diff --git a/meson_options.txt b/meson_options.txt
> index 7b8cf3f35..3405c1b73 100644
> --- a/meson_options.txt
> +++ b/meson_options.txt
> @@ -162,7 +162,7 @@ option('build-pipesz', type : 'feature',
> option('build-setterm', type : 'feature',
> description : 'build setterm')
> option('build-schedutils', type : 'feature',
> - description : 'build chrt, ionice, taskset')
> + description : 'build chrt, ionice, taskset, coresched')
> option('build-wall', type : 'feature',
> description : 'build wall')
> option('build-write', type : 'feature',
> diff --git a/schedutils/Makemodule.am b/schedutils/Makemodule.am
> index 1040da85f..0cb655401 100644
> --- a/schedutils/Makemodule.am
> +++ b/schedutils/Makemodule.am
> @@ -29,3 +29,11 @@ dist_noinst_DATA += schedutils/uclampset.1.adoc
> uclampset_SOURCES = schedutils/uclampset.c schedutils/sched_attr.h
> uclampset_LDADD = $(LDADD) libcommon.la
> endif
> +
> +if BUILD_CORESCHED
> +usrbin_exec_PROGRAMS += coresched
> +MANPAGES += schedutils/coresched.1
> +dist_noinst_DATA += schedutils/coresched.1.adoc
> +coresched_SOURCES = schedutils/coresched.c
> +coresched_LDADD = $(LDADD) libcommon.la
> +endif
> diff --git a/schedutils/coresched.1.adoc b/schedutils/coresched.1.adoc
> new file mode 100644
> index 000000000..00f2603e0
> --- /dev/null
> +++ b/schedutils/coresched.1.adoc
> @@ -0,0 +1,138 @@
> +//po4a: entry man manual
> +////
> +coresched(1) manpage
> +////
> += coresched(1)
> +:doctype: manpage
> +:man manual: User Commands
> +:man source: util-linux {release-version}
> +:page-layout: base
> +:command: coresched
> +:colon: :
> +:copyright: ©
> +
> +== NAME
> +
> +coresched - manage core scheduling cookies for tasks
> +
> +== SYNOPSIS
> +
> +*{command}* [*get*] [*-s* _pid_]
> +
> +*{command}* *new* [*-t* _type_] *-d* _pid_
> +
> +*{command}* *new* [*-t* _type_] \-- _command_ [_argument_...]
> +
> +*{command}* *copy* [*-s* _pid_] [*-t* _type_] *-d* _pid_
> +
> +*{command}* *copy* [*-s* _pid_] [*-t* _type_] \-- _command_ [_argument_...]
> +
> +== DESCRIPTION
> +The *{command}* command is used to retrieve or modify the core scheduling cookies of a running process given its _pid_, or to spawn a new _command_ with core scheduling cookies.
> +
> +Core scheduling allows you to define groups of tasks that are allowed to share a physical core.
> +This is done by assigning a cookie to each task.
> +Only tasks have the same cookie are allowed to be scheduled on the same physical core.
> +
> +It is possible to either assign a new random cookie to a task, or copy a cookie from another task. It is not possible to choose the value of the cookie.
> +
> +== FUNCTIONS
> +*get*::
> +Retrieve the core scheduling cookie of the PID specified in *-s*.
> +If *-s* is omitted, it will get the cookie of the current *{command}* process.
> +
> +*new*::
> +Assign a new cookie to an existing PID specified in *-d*, or execute _command_ with a new cookie.
> +
> +*copy*::
> +Copy the cookie from an existing PID (*-s*) to another PID (*-d*), or execute _command_ with that cookie.
> +If *-s* is omitted, it will get the cookie of the current *{command}* process.
> +
> +If no function is specified, it will run the *get* function.
> +
> +== OPTIONS
> +*-s*, *--source* _PID_::
> +Which _PID_ to get the cookie from.
> +If this option is omitted, it will get the cookie from the current *{command}* process.
> +
> +*-d*, *--dest* _PID_::
> +Which _PID_ to modify the cookie of.
> +
> +*-t*, *--dest-type* _TYPE_::
> +The type of the PID whose cookie will be modified. This can be one of three values:
> +- *pid*, or process ID
> +- *tgid*, or thread group ID (default value)
> +- *pgid*, or process group ID
> +
> +*-v*, *--verbose*::
> +Show extra information when modifying cookies of tasks.
> +
> +*-h*, *--help*::
> +Display help text and exit.
> +
> +*-V*, *--version*::
> +Print version and exit.
> +
> +== EXAMPLES
> +Get the core scheduling cookie of the {command} task itself, usually inherited from its parent{colon}::
> +*{command} get*
> +
> +Get the core scheduling cookie of a task with PID _123_{colon}::
> +*{command} get -s* _123_
> +
> +Give a task with PID _123_ a new core scheduling cookie{colon}::
> +*{command} new -d* _123_
> +
> +Spawn a new task with a new core scheduling cookie{colon}::
> +*{command} new* \-- _command_ [_argument_...]
> +
> +Copy the cookie from the current {command} process another task with pid _456_{colon}::
> +*{command} copy -d* _456_
> +
> +Copy the cookie from a task with pid _123_ to another task with pid _456_{colon}::
> +*{command} copy -s* _123_ *-d* _456_
> +
> +Copy the cookie from a task with pid _123_ to a new task _command_{colon}::
> +*{command} copy -s* _123_ \-- _command_ [_argument_...]
> +
> +Copy the cookie from a task with pid _123_ to the process group ID _456_{colon}::
> +*{command} copy -s* _123_ *-t* _pgid_ *-d* _456_
> +
> +== PERMISSIONS
> +When retrieving or modifying the core scheduling cookie of a process, you need to have *PTRACE_MODE_READ_REALCREDS* ptrace access to that process.
> +See the section "Ptrace access mode checking" in *ptrace*(2) for more information.
> +
> +== RETURN VALUE
> +On success, *{command}* returns 0.
> +If *{command}* fails, it will print an error and return 1.
> +
> +If a _command_ is being executed, the return value of *{command}* will be the return value of _command_.
> +
> +== NOTES
> +*{command}* requires core scheduling support in the kernel.
> +This can be enabled via the *CONFIG_SCHED_CORE* kernel config option.
> +
> +== AUTHORS
> +mailto:thijs@xxxxxxxxxxxx[Thijs Raymakers]
> +
> +== COPYRIGHT
> +
> +Copyright {copyright} 2024 Thijs Raymakers. This is free software licensed under the EUPL.
> +
> +== SEE ALSO
> +*chrt*(1),
> +*nice*(1),
> +*renice*(1),
> +*taskset*(1),
> +*ptrace*(2),
> +*sched*(7)
> +
> +The Linux kernel source files _Documentation/admin-guide/hw-vuln/core-scheduling.rst_
> +
> +include::man-common/bugreports.adoc[]
> +
> +include::man-common/footer.adoc[]
> +
> +ifdef::translation[]
> +include::man-common/translation.adoc[]
> +endif::[]
> diff --git a/schedutils/coresched.c b/schedutils/coresched.c
> new file mode 100644
> index 000000000..7e3cc46d2
> --- /dev/null
> +++ b/schedutils/coresched.c
> @@ -0,0 +1,358 @@
> +/**
> + * SPDX-License-Identifier: EUPL-1.2
> + *
> + * coresched.c - manage core scheduling cookies for tasks
> + *
> + * Copyright (C) 2024 Thijs Raymakers
> + * Licensed under the EUPL v1.2
> + */
> +
> +#include <getopt.h>
> +#include <stdbool.h>
> +#include <stdio.h>
> +#include <sys/prctl.h>
> +#include <unistd.h>
> +
> +#include "c.h"
> +#include "closestream.h"
> +#include "nls.h"
> +#include "strutils.h"
> +
> +// These definitions might not be defined in the header files, even if the
> +// prctl interface in the kernel accepts them as valid.
> +#ifndef PR_SCHED_CORE
> + #define PR_SCHED_CORE 62
> +#endif
> +#ifndef PR_SCHED_CORE_GET
> + #define PR_SCHED_CORE_GET 0
> +#endif
> +#ifndef PR_SCHED_CORE_CREATE
> + #define PR_SCHED_CORE_CREATE 1
> +#endif
> +#ifndef PR_SCHED_CORE_SHARE_TO
> + #define PR_SCHED_CORE_SHARE_TO 2
> +#endif
> +#ifndef PR_SCHED_CORE_SHARE_FROM
> + #define PR_SCHED_CORE_SHARE_FROM 3
> +#endif
> +#ifndef PR_SCHED_CORE_SCOPE_THREAD
> + #define PR_SCHED_CORE_SCOPE_THREAD 0
> +#endif
> +#ifndef PR_SCHED_CORE_SCOPE_THREAD_GROUP
> + #define PR_SCHED_CORE_SCOPE_THREAD_GROUP 1
> +#endif
> +#ifndef PR_SCHED_CORE_SCOPE_PROCESS_GROUP
> + #define PR_SCHED_CORE_SCOPE_PROCESS_GROUP 2
> +#endif
> +
> +typedef int sched_core_scope;
> +typedef unsigned long sched_core_cookie;
> +typedef enum {
> + SCHED_CORE_CMD_GET,
> + SCHED_CORE_CMD_NEW,
> + SCHED_CORE_CMD_COPY,
> +} sched_core_cmd;
> +
> +struct args {
> + pid_t src;
> + pid_t dest;
> + sched_core_scope type;
> + sched_core_cmd cmd;
> + int exec_argv_offset;
> +};
> +
> +static bool sched_core_verbose = false;
> +
> +static void __attribute__((__noreturn__)) usage(void)
> +{
> + fputs(USAGE_HEADER, stdout);
> + fprintf(stdout, _(" %s [get] [--source <PID>]\n"),
> + program_invocation_short_name);
> + fprintf(stdout, _(" %s new [-t <TYPE>] --dest <PID>\n"),
> + program_invocation_short_name);
> + fprintf(stdout, _(" %s new [-t <TYPE>] -- PROGRAM [ARGS...]\n"),
> + program_invocation_short_name);
> + fprintf(stdout,
> + _(" %s copy [--source <PID>] [-t <TYPE>] --dest <PID>\n"),
> + program_invocation_short_name);
> + fprintf(stdout,
> + _(" %s copy [--source <PID>] [-t <TYPE>] -- PROGRAM [ARGS...]\n"),
> + program_invocation_short_name);
> +
> + fputs(USAGE_SEPARATOR, stdout);
> + fputsln(_("Manage core scheduling cookies for tasks."), stdout);
> +
> + fputs(USAGE_FUNCTIONS, stdout);
> + fputsln(_(" get retrieve the core scheduling cookie of a PID"),
> + stdout);
> + fputsln(_(" new assign a new core scheduling cookie to an existing\n"
> + " PID or execute a program with a new cookie"),
> + stdout);
> + fputsln(_(" copy copy the core scheduling cookie from an existing PID\n"
> + " to another PID, or execute a program with that\n"
> + " copied cookie"),
> + stdout);
> +
> + fputs(USAGE_OPTIONS, stdout);
> + fprintf(stdout,
> + _(" -s, --source <PID> which PID to get the cookie from\n"
> + " If omitted, it is the PID of %s itself\n"),
> + program_invocation_short_name);
> + fputsln(_(" -d, --dest <PID> which PID to modify the cookie of\n"),
> + stdout);
> + fputsln(_(" -t, --dest-type <TYPE> type of the destination PID, or the type of the PID\n"
> + " when a new core scheduling cookie is created.\n"
> + " Can be one of the following: pid, tgid or pgid.\n"
> + " The default is tgid."),
> + stdout);
> + fputs(USAGE_SEPARATOR, stdout);
> + fputsln(_(" -v, --verbose verbose"), stdout);
> + fprintf(stdout, USAGE_HELP_OPTIONS(20));
> + fprintf(stdout, USAGE_MAN_TAIL("coresched(1)"));
> + exit(EXIT_SUCCESS);
> +}
> +
> +#define bad_usage(FMT...) \
> + do { \
> + warnx(FMT); \
> + errtryhelp(EXIT_FAILURE); \
> + } while (0)
> +
> +static sched_core_cookie core_sched_get_cookie(pid_t pid)
> +{
> + sched_core_cookie cookie = 0;
> + if (prctl(PR_SCHED_CORE, PR_SCHED_CORE_GET, pid,
> + PR_SCHED_CORE_SCOPE_THREAD, &cookie))
> + err(EXIT_FAILURE, _("Failed to get cookie from PID %d"), pid);
> + return cookie;
> +}
> +
> +static void core_sched_create_cookie(pid_t pid, sched_core_scope type)
> +{
> + if (prctl(PR_SCHED_CORE, PR_SCHED_CORE_CREATE, pid, type, 0))
> + err(EXIT_FAILURE, _("Failed to create cookie for PID %d"), pid);
> +}
> +
> +static void core_sched_pull_cookie(pid_t from)
> +{
> + if (prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_FROM, from,
> + PR_SCHED_CORE_SCOPE_THREAD, 0))
> + err(EXIT_FAILURE, _("Failed to pull cookie from PID %d"), from);
> +}
> +
> +static void core_sched_push_cookie(pid_t to, sched_core_scope type)
> +{
> + if (prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, to, type, 0))
> + err(EXIT_FAILURE, _("Failed to push cookie to PID %d"), to);
> +}
> +
> +static void core_sched_copy_cookie(pid_t from, pid_t to,
> + sched_core_scope to_type)
> +{
> + core_sched_pull_cookie(from);
> + core_sched_push_cookie(to, to_type);
> +
> + if (sched_core_verbose) {
> + sched_core_cookie before = core_sched_get_cookie(from);
> + warnx(_("copied cookie 0x%lx from PID %d to PID %d"), before,
> + from, to);
> + }
> +}
> +
> +static void core_sched_get_and_print_cookie(pid_t pid)
> +{
> + if (sched_core_verbose) {
> + sched_core_cookie after = core_sched_get_cookie(pid);
> + warnx(_("set cookie of PID %d to 0x%lx"), pid, after);
> + }
> +}
> +
> +static void core_sched_exec_with_cookie(struct args *args, char **argv)
> +{
> + // Move the argument list to the first argument of the program
> + argv = &argv[args->exec_argv_offset];
> +
> + // If a source PID is provided, try to copy the cookie from
> + // that PID. Otherwise, create a brand new cookie with the
> + // provided type.
> + if (args->src) {
> + core_sched_pull_cookie(args->src);
> + core_sched_get_and_print_cookie(args->src);
> + } else {
> + pid_t pid = getpid();
> + core_sched_create_cookie(pid, args->type);
> + core_sched_get_and_print_cookie(pid);
> + }
> +
> + if (execvp(argv[0], argv))
> + errexec(argv[0]);
> +}
> +
> +// If PR_SCHED_CORE is not recognized, or not supported on this system,
> +// then prctl will set errno to EINVAL. Assuming all other operands of
> +// prctl are valid, we can use errno==EINVAL as a check to see whether
> +// core scheduling is available on this system.
> +static bool is_core_sched_supported(void)
> +{
> + sched_core_cookie cookie = 0;
> + if (prctl(PR_SCHED_CORE, PR_SCHED_CORE_GET, getpid(),
> + PR_SCHED_CORE_SCOPE_THREAD, &cookie))
> + if (errno == EINVAL)
> + return false;
> +
> + return true;
> +}
> +
> +static sched_core_scope parse_core_sched_type(char *str)
> +{
> + if (!strcmp(str, "pid"))
> + return PR_SCHED_CORE_SCOPE_THREAD;
> + else if (!strcmp(str, "tgid"))
> + return PR_SCHED_CORE_SCOPE_THREAD_GROUP;
> + else if (!strcmp(str, "pgid"))
> + return PR_SCHED_CORE_SCOPE_PROCESS_GROUP;
> +
> + bad_usage(_("'%s' is an invalid option. Must be one of pid/tgid/pgid"),
> + str);
> +}
> +
> +static void parse_and_verify_arguments(int argc, char **argv, struct args *args)
> +{
> + int c;
> +
> + static const struct option longopts[] = {
> + { "source", required_argument, NULL, 's' },
> + { "dest", required_argument, NULL, 'd' },
> + { "dest-type", required_argument, NULL, 't' },
> + { "verbose", no_argument, NULL, 'v' },
> + { "version", no_argument, NULL, 'V' },
> + { "help", no_argument, NULL, 'h' },
> + { NULL, 0, NULL, 0 }
> + };
> +
> + while ((c = getopt_long(argc, argv, "s:d:t:vVh", longopts, NULL)) != -1)
> + switch (c) {
> + case 's':
> + args->src = strtopid_or_err(
> + optarg,
> + _("Failed to parse PID for -s/--source"));
> + break;
> + case 'd':
> + args->dest = strtopid_or_err(
> + optarg, _("Failed to parse PID for -d/--dest"));
> + break;
> + case 't':
> + args->type = parse_core_sched_type(optarg);
> + break;
> + case 'v':
> + sched_core_verbose = true;
> + break;
> + case 'V':
> + print_version(EXIT_SUCCESS);
> + case 'h':
> + usage();
> + default:
> + errtryhelp(EXIT_FAILURE);
> + }
> +
> + if (argc <= optind) {
> + args->cmd = SCHED_CORE_CMD_GET;
> + } else {
> + if (!strcmp(argv[optind], "get"))
> + args->cmd = SCHED_CORE_CMD_GET;
> + else if (!strcmp(argv[optind], "new"))
> + args->cmd = SCHED_CORE_CMD_NEW;
> + else if (!strcmp(argv[optind], "copy"))
> + args->cmd = SCHED_CORE_CMD_COPY;
> + else
> + bad_usage(_("Unknown function"));
> +
> + // Since we parsed an extra "option" outside of getopt_long, we have to
> + // increment optind manually.
> + ++optind;
> + }
> +
> + if (args->cmd == SCHED_CORE_CMD_GET && args->dest)
> + bad_usage(_("get does not accept the --dest option"));
> +
> + if (args->cmd == SCHED_CORE_CMD_NEW && args->src)
> + bad_usage(_("new does not accept the --source option"));
> +
> + // If the -s/--source option is not specified, it defaults to the PID
> + // of the current coresched process
> + if (args->cmd != SCHED_CORE_CMD_NEW && !args->src)
> + args->src = getpid();
> +
> + // More arguments have been passed, which means that the user wants to run
> + // another program with a core scheduling cookie.
> + if (argc > optind) {
> + switch (args->cmd) {
> + case SCHED_CORE_CMD_GET:
> + bad_usage(_("bad usage of the get function"));
> + break;
> + case SCHED_CORE_CMD_NEW:
> + if (args->dest)
> + bad_usage(_(
> + "new requires either a -d/--dest or a command"));
> + else
> + args->exec_argv_offset = optind;
> + break;
> + case SCHED_CORE_CMD_COPY:
> + if (args->dest)
> + bad_usage(_(
> + "copy requires either a -d/--dest or a command"));
> + else
> + args->exec_argv_offset = optind;
> + break;
> + }
> + } else {
> + if (args->cmd == SCHED_CORE_CMD_NEW && !args->dest)
> + bad_usage(_(
> + "new requires either a -d/--dest or a command"));
> + if (args->cmd == SCHED_CORE_CMD_COPY && !args->dest)
> + bad_usage(_(
> + "copy requires either a -d/--dest or a command"));
> + }
> +}
> +
> +int main(int argc, char **argv)
> +{
> + struct args args = { .type = PR_SCHED_CORE_SCOPE_THREAD_GROUP };
> +
> + setlocale(LC_ALL, "");
> + bindtextdomain(PACKAGE, LOCALEDIR);
> + textdomain(PACKAGE);
> + close_stdout_atexit();
> +
> + parse_and_verify_arguments(argc, argv, &args);
> +
> + if (!is_core_sched_supported())
> + errx(EXIT_FAILURE,
> + _("No support for core scheduling found. Does your kernel"
> + "support CONFIG_SCHED_CORE?"));
> +
> + sched_core_cookie cookie;
> +
> + switch (args.cmd) {
> + case SCHED_CORE_CMD_GET:
> + cookie = core_sched_get_cookie(args.src);
> + printf(_("cookie of pid %d is 0x%lx\n"), args.src, cookie);
> + break;
> + case SCHED_CORE_CMD_NEW:
> + if (args.exec_argv_offset) {
> + core_sched_exec_with_cookie(&args, argv);
> + } else {
> + core_sched_create_cookie(args.dest, args.type);
> + core_sched_get_and_print_cookie(args.dest);
> + }
> + break;
> + case SCHED_CORE_CMD_COPY:
> + if (args.exec_argv_offset)
> + core_sched_exec_with_cookie(&args, argv);
> + else
> + core_sched_copy_cookie(args.src, args.dest, args.type);
> + break;
> + default:
> + usage();
> + }
> +}
> diff --git a/tests/commands.sh b/tests/commands.sh
> index 5674c5ff0..9eef92ccb 100644
> --- a/tests/commands.sh
> +++ b/tests/commands.sh
> @@ -71,6 +71,7 @@ TS_CMD_COLCRT=${TS_CMD_COLCRT:-"${ts_commandsdir}colcrt"}
> TS_CMD_COLRM=${TS_CMD_COLRM:-"${ts_commandsdir}colrm"}
> TS_CMD_COL=${TS_CMD_COL:-"${ts_commandsdir}col"}
> TS_CMD_COLUMN=${TS_CMD_COLUMN:-"${ts_commandsdir}column"}
> +TS_CMD_CORESCHED=${TS_CMD_CORESCHED:-"${ts_commandsdir}coresched"}
> TS_CMD_ENOSYS=${TS_CMD_ENOSYS-"${ts_commandsdir}enosys"}
> TS_CMD_EJECT=${TS_CMD_EJECT-"${ts_commandsdir}eject"}
> TS_CMD_EXCH=${TS_CMD_EXCH-"${ts_commandsdir}exch"}
> diff --git a/tests/expected/schedutils/coresched-copy-from-child-to-parent b/tests/expected/schedutils/coresched-copy-from-child-to-parent
> new file mode 100644
> index 000000000..5b9c40052
> --- /dev/null
> +++ b/tests/expected/schedutils/coresched-copy-from-child-to-parent
> @@ -0,0 +1 @@
> +DIFFERENT_COOKIE
> diff --git a/tests/expected/schedutils/coresched-copy-from-parent-to-nested-child b/tests/expected/schedutils/coresched-copy-from-parent-to-nested-child
> new file mode 100644
> index 000000000..ecfc41142
> --- /dev/null
> +++ b/tests/expected/schedutils/coresched-copy-from-parent-to-nested-child
> @@ -0,0 +1 @@
> +SAME_COOKIE
> diff --git a/tests/expected/schedutils/coresched-get-cookie-own-pid b/tests/expected/schedutils/coresched-get-cookie-own-pid
> new file mode 100644
> index 000000000..84f182cbe
> --- /dev/null
> +++ b/tests/expected/schedutils/coresched-get-cookie-own-pid
> @@ -0,0 +1 @@
> +cookie of pid OWN_PID is PARENT_COOKIE
> diff --git a/tests/expected/schedutils/coresched-get-cookie-parent-pid b/tests/expected/schedutils/coresched-get-cookie-parent-pid
> new file mode 100644
> index 000000000..e183e0402
> --- /dev/null
> +++ b/tests/expected/schedutils/coresched-get-cookie-parent-pid
> @@ -0,0 +1 @@
> +cookie of pid PARENT_PID is PARENT_COOKIE
> diff --git a/tests/expected/schedutils/coresched-new-child-with-new-cookie b/tests/expected/schedutils/coresched-new-child-with-new-cookie
> new file mode 100644
> index 000000000..5b9c40052
> --- /dev/null
> +++ b/tests/expected/schedutils/coresched-new-child-with-new-cookie
> @@ -0,0 +1 @@
> +DIFFERENT_COOKIE
> diff --git a/tests/expected/schedutils/coresched-set-cookie-parent-pid.err b/tests/expected/schedutils/coresched-set-cookie-parent-pid.err
> new file mode 100644
> index 000000000..e7318ffc2
> --- /dev/null
> +++ b/tests/expected/schedutils/coresched-set-cookie-parent-pid.err
> @@ -0,0 +1 @@
> +coresched: set cookie of PID PARENT_PID to PARENT_COOKIE
> diff --git a/tests/expected/schedutils/set-cookie-parent-pid b/tests/expected/schedutils/set-cookie-parent-pid
> new file mode 100644
> index 000000000..e7318ffc2
> --- /dev/null
> +++ b/tests/expected/schedutils/set-cookie-parent-pid
> @@ -0,0 +1 @@
> +coresched: set cookie of PID PARENT_PID to PARENT_COOKIE
> diff --git a/tests/ts/schedutils/coresched b/tests/ts/schedutils/coresched
> new file mode 100755
> index 000000000..e34fa319f
> --- /dev/null
> +++ b/tests/ts/schedutils/coresched
> @@ -0,0 +1,83 @@
> +#!/bin/bash
> +# SPDX-License-Identifier: EUPL-1.2
> +#
> +# This file is part of util-linux
> +#
> +# Copyright (C) 2024 Thijs Raymakers
> +# Licensed under the EUPL v1.2
> +
> +TS_TOPDIR="${0%/*}/../.."
> +TS_DESC="coresched"
> +
> +. "$TS_TOPDIR"/functions.sh
> +ts_init "$*"
> +
> +ts_check_test_command "$TS_CMD_CORESCHED"
> +ts_check_prog "tee"
> +ts_check_prog "sed"
> +
> +# If there is no kernel support, skip the test suite
> +CORESCHED_TEST_KERNEL_SUPPORT_CMD=$($TS_CMD_CORESCHED 2>&1)
> +if [[ $CORESCHED_TEST_KERNEL_SUPPORT_CMD == *"CONFIG_SCHED_CORE"* ]]; then
> + ts_skip "Kernel has no CONFIG_SCHED_CORE support"
> +fi
> +
> +# The output of coresched contains PIDs and core scheduling cookies, both of which should be
> +# assumed to be random values as we have no control over them. The tests replace these values
> +# with sed before writing them to the output file, so it can match the expected output file.
> +# - The PID of this bash script is replaced with the placeholder `OWN_PID`
> +# - The core scheduling cookie of this bash script is replaced by `COOKIE`
> +# - Any other cookie is replaced by `DIFFERENT_COOKIE`
> +# The behavior of coresched does not depend on the exact values of these cookies, so using
> +# placeholder values does not change the behavior tests.
> +ts_init_subtest "set-cookie-parent-pid"
> +CORESCHED_OUTPUT=$( ($TS_CMD_CORESCHED -v new -d $$ \
> + | tee -a "$TS_OUTPUT") 3>&1 1>&2 2>&3 \
> + | sed "s/$$/PARENT_PID/g")
> +CORESCHED_PARENT_COOKIE=$(echo "$CORESCHED_OUTPUT" | sed 's/^.*\(0x.*$\)/\1/g')
> +if [ -z "$CORESCHED_PARENT_COOKIE" ]; then
> + ts_failed "empty value for CORESCHED_PARENT_COOKIE"
> +fi
> +CORESCHED_OUTPUT=$(echo "$CORESCHED_OUTPUT" \
> + | sed "s/$CORESCHED_PARENT_COOKIE/PARENT_COOKIE/g")
> +echo "$CORESCHED_OUTPUT" >> "$TS_ERRLOG"
> +ts_finalize_subtest
> +
> +ts_init_subtest "get-cookie-parent-pid"
> +$TS_CMD_CORESCHED get -s $$ 2>> "$TS_ERRLOG" \
> + | sed -e "s/$$/PARENT_PID/g" \
> + -e "s/$CORESCHED_PARENT_COOKIE/PARENT_COOKIE/g" >> "$TS_OUTPUT"
> +ts_finalize_subtest
> +
> +ts_init_subtest "get-cookie-own-pid"
> +$TS_CMD_CORESCHED get 2>> "$TS_ERRLOG" \
> + | sed -e "s/pid [0-9]\+/pid OWN_PID/g" \
> + -e "s/$CORESCHED_PARENT_COOKIE/PARENT_COOKIE/g" >> "$TS_OUTPUT"
> +ts_finalize_subtest
> +
> +ts_init_subtest "new-child-with-new-cookie"
> +$TS_CMD_CORESCHED new -- "$TS_CMD_CORESCHED" get 2>> "$TS_ERRLOG" \
> + | sed -e 's/^.*\(0x.*$\)/\1/g' \
> + -e "s/$CORESCHED_PARENT_COOKIE/SAME_COOKIE/g" \
> + -e "s/0x.*$/DIFFERENT_COOKIE/g" >> "$TS_OUTPUT"
> +ts_finalize_subtest
> +
> +ts_init_subtest "copy-from-parent-to-nested-child"
> +$TS_CMD_CORESCHED new -- /bin/bash -c \
> + "$TS_CMD_CORESCHED copy -s $$ -- $TS_CMD_CORESCHED get" \
> +2>> "$TS_ERRLOG" \
> + | sed -e 's/^.*\(0x.*$\)/\1/g' \
> + -e "s/$CORESCHED_PARENT_COOKIE/SAME_COOKIE/g" \
> + -e "s/0x.*$/DIFFERENT_COOKIE/g" >> "$TS_OUTPUT"
> +ts_finalize_subtest
> +
> +ts_init_subtest "copy-from-child-to-parent"
> +$TS_CMD_CORESCHED new -- /bin/bash -c \
> + "$TS_CMD_CORESCHED copy -s \$\$ -d $$"
> +$TS_CMD_CORESCHED get 2>> "$TS_ERRLOG" \
> + | sed -e 's/^.*\(0x.*$\)/\1/g' \
> + -e "s/$CORESCHED_PARENT_COOKIE/SAME_COOKIE/g" \
> + -e "s/0x.*$/DIFFERENT_COOKIE/g" >> "$TS_OUTPUT"
> +ts_finalize_subtest
> +
> +ts_finalize
> --
> 2.44.0
>
--
