On Mon, 23 May 2022, Yihao Wu wrote:
> We observerved strange performance regression with hackbench, but only with
> its default mode instead of pipe mode. It turned out it was unix domain
> socket to blame rather than the scheduler. Because on older kernels, there
> was a big lock. And modifications to the scheduler made the contension
> worse.
>
> However pipe mode is much different from the default af_unix mode. So it's
> hard to prove it's really the case. So we think it might be a good idea to
> have af_inet mode for hackbench.
>
> After implementing it, we compare these three modes. And the result shows
> as what we expect, that only af_unix mode has regression, the others don't.
> This proves adding af_inet mode is valuable.
>
> Signed-off-by: Yihao Wu <wuyihao@xxxxxxxxxxxxxxxxx>
> ---
> v1->v2: Drop the first patch
> v2->v3: Fix EOLs in the commit log
>
> src/hackbench/hackbench.c | 57 ++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 56 insertions(+), 1 deletion(-)
>
> diff --git a/src/hackbench/hackbench.c b/src/hackbench/hackbench.c
> index 268c232..18c9284 100644
> --- a/src/hackbench/hackbench.c
> +++ b/src/hackbench/hackbench.c
> @@ -20,11 +20,14 @@
> #include <string.h>
> #include <errno.h>
> #include <unistd.h>
> +#include <sys/ioctl.h>
> #include <sys/types.h>
> #include <sys/socket.h>
> #include <sys/wait.h>
> #include <sys/time.h>
> #include <sys/poll.h>
> +#include <netinet/in.h>
> +#include <arpa/inet.h>
> #include <limits.h>
> #include <getopt.h>
> #include <signal.h>
> @@ -46,6 +49,7 @@ static unsigned int fifo = 0;
> static unsigned int process_mode = PROCESS_MODE;
>
> static int use_pipes = 0;
> +static int use_inet = 0;
>
> struct sender_context {
> unsigned int num_fds;
> @@ -99,6 +103,7 @@ static void print_usage_exit(int error)
> "-h --help print this message\n"
> "-l --loops=LOOPS how many message should be send\n"
> "-p --pipe send data via a pipe\n"
> + "-i --inet send data via a inet tcp connection\n"
> "-s --datasize=SIZE message size\n"
> "-T --threads use POSIX threads\n"
> "-P --process use fork (default)\n"
> @@ -106,11 +111,52 @@ static void print_usage_exit(int error)
> exit(error);
> }
>
> +static int inet_socketpair(int fds[2])
> +{
> + int s1, s2;
> + struct sockaddr_in sin;
> + unsigned long ul = 1;
> +
> + if ((s1 = socket(AF_INET, SOCK_STREAM, 0)) < 0)
> + barf("socket");
> + if ((s2 = socket(AF_INET, SOCK_STREAM, 0)) < 0)
> + barf("socket");
> +
> + socklen_t len = sizeof(sin);
> + bzero(&sin, len);
> + sin.sin_family = AF_INET;
> + sin.sin_port = 0;
> + sin.sin_addr.s_addr = inet_addr("127.0.0.1");
> +
> + if (bind(s1, &sin, len) < 0)
> + barf("bind");
> + getsockname(s1, &sin, &len);
> + if (listen(s1, 10) < 0)
> + barf("listen");
> + if (ioctl(s2, FIONBIO, &ul) < 0)
> + barf("ioctl");
> + if (ioctl(s1, FIONBIO, &ul) < 0)
> + barf("ioctl");
> + connect(s2, &sin, len);
> + if ((fds[0] = accept(s1, &sin, &len)) < 0)
> + barf("accept");
> + ul = 0;
> + if (ioctl(s2, FIONBIO, &ul) < 0)
> + barf("ioctl");
> + fds[1] = s2;
> + close(s1);
> +
> + return 0;
> +}
> +
> static void fdpair(int fds[2])
> {
> if (use_pipes) {
> if (pipe(fds) == 0)
> return;
> + } else if (use_inet) {
> + if (inet_socketpair(fds) == 0)
> + return;
> } else {
> if (socketpair(AF_UNIX, SOCK_STREAM, 0, fds) == 0)
> return;
> @@ -364,13 +410,14 @@ static void process_options(int argc, char *argv[])
> {"help", no_argument, NULL, 'h'},
> {"loops", required_argument, NULL, 'l'},
> {"pipe", no_argument, NULL, 'p'},
> + {"inet", no_argument, NULL, 'i'},
> {"datasize", required_argument, NULL, 's'},
> {"threads", no_argument, NULL, 'T'},
> {"processes", no_argument, NULL, 'P'},
> {NULL, 0, NULL, 0}
> };
>
> - int c = getopt_long(argc, argv, "f:Fg:hl:ps:TP",
> + int c = getopt_long(argc, argv, "f:Fg:hl:pis:TP",
> longopts, &optind);
> if (c == -1) {
> break;
> @@ -402,6 +449,9 @@ static void process_options(int argc, char *argv[])
> case 'p':
> use_pipes = 1;
> break;
> + case 'i':
> + use_inet = 1;
> + break;
> case 's':
> if (!(argv[optind] && (datasize = atoi(optarg)) > 0)) {
> fprintf(stderr, "%s: --datasize|-s requires an integer > 0\n", argv[0]);
> @@ -418,6 +468,11 @@ static void process_options(int argc, char *argv[])
> print_usage_exit(1);
> }
> }
> +
> + if (use_pipes && use_inet) {
> + fprintf(stderr, "%s: --pipe|-p and --inet|-i cannot be used together\n", argv[0]);
> + print_usage_exit(1);
> + }
> }
>
> void sigcatcher(int sig) {
> --
> 2.32.0.604.gb1f3e1269
>
>
Signed-off-by: John Kacur <jkacur@xxxxxxxxxx>
