On Tue, 18 May 2021, Jonathan Schwender wrote:
> This allows the user to specify a separate cpuset for the main pid,
> e.g. on a housekeeping CPU.
> If --mainaffinity is not specified, but --affinity is, then the
> current behaviour is preserved and the main thread is bound
> to the cpuset specified by --affinity
>
> Signed-off-by: Jonathan Schwender <schwenderjonathan@xxxxxxxxx>
> ---
> src/cyclictest/cyclictest.c | 20 ++++++++++++++++++--
> 1 file changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/src/cyclictest/cyclictest.c b/src/cyclictest/cyclictest.c
> index 3bab3b2..a2103c7 100644
> --- a/src/cyclictest/cyclictest.c
> +++ b/src/cyclictest/cyclictest.c
> @@ -836,6 +836,8 @@ static void display_help(int error)
> " --laptop Save battery when running cyclictest\n"
> " This will give you poorer realtime results\n"
> " but will not drain your battery so quickly\n"
> + " --mainaffinity=[CPUSET] Run the main thread on CPU #N. This only affects\n"
> + " the main thread and not the measurement threads\n"
> "-m --mlockall lock current and future memory allocations\n"
> "-M --refresh_on_max delay updating the screen until a new max\n"
> " latency is hit. Useful for low bandwidth.\n"
> @@ -891,6 +893,7 @@ static int quiet;
> static int interval = DEFAULT_INTERVAL;
> static int distance = -1;
> static struct bitmask *affinity_mask = NULL;
> +static struct bitmask *main_affinity_mask = NULL;
> static int smp = 0;
> static int setaffinity = AFFINITY_UNSPECIFIED;
>
> @@ -944,7 +947,7 @@ enum option_values {
> OPT_AFFINITY=1, OPT_BREAKTRACE, OPT_CLOCK,
> OPT_DISTANCE, OPT_DURATION, OPT_LATENCY,
> OPT_FIFO, OPT_HISTOGRAM, OPT_HISTOFALL, OPT_HISTFILE,
> - OPT_INTERVAL, OPT_LOOPS, OPT_MLOCKALL, OPT_REFRESH,
> + OPT_INTERVAL, OPT_LOOPS, OPT_MAINAFFINITY, OPT_MLOCKALL, OPT_REFRESH,
> OPT_NANOSLEEP, OPT_NSECS, OPT_OSCOPE, OPT_PRIORITY,
> OPT_QUIET, OPT_PRIOSPREAD, OPT_RELATIVE, OPT_RESOLUTION,
> OPT_SYSTEM, OPT_SMP, OPT_THREADS, OPT_TRIGGER,
> @@ -981,6 +984,7 @@ static void process_options(int argc, char *argv[], int max_cpus)
> {"interval", required_argument, NULL, OPT_INTERVAL },
> {"laptop", no_argument, NULL, OPT_LAPTOP },
> {"loops", required_argument, NULL, OPT_LOOPS },
> + {"mainaffinity", required_argument, NULL, OPT_MAINAFFINITY},
> {"mlockall", no_argument, NULL, OPT_MLOCKALL },
> {"refresh_on_max", no_argument, NULL, OPT_REFRESH },
> {"nsecs", no_argument, NULL, OPT_NSECS },
> @@ -1083,6 +1087,16 @@ static void process_options(int argc, char *argv[], int max_cpus)
> case 'l':
> case OPT_LOOPS:
> max_cycles = atoi(optarg); break;
> + case OPT_MAINAFFINITY:
> + if (optarg) {
> + parse_cpumask(optarg, max_cpus, &main_affinity_mask);
> + } else if (optind < argc &&
> + (atoi(argv[optind]) ||
> + argv[optind][0] == '0' ||
> + argv[optind][0] == '!')) {
> + parse_cpumask(argv[optind], max_cpus, &main_affinity_mask);
> + }
> + break;
> case 'm':
> case OPT_MLOCKALL:
> lockall = 1; break;
> @@ -1802,7 +1816,9 @@ int main(int argc, char **argv)
> }
>
> /* Restrict the main pid to the affinity specified by the user */
> - if (affinity_mask != NULL) {
> + if (main_affinity_mask != NULL) {
> + set_main_thread_affinity(main_affinity_mask);
Am I missing something here, if there is a main_affinity_mask we set that
but then skip over the affinity_mask. Don't we want to check both?
> + } else if (affinity_mask != NULL) {
> set_main_thread_affinity(affinity_mask);
> if (verbose)
> printf("Using %u cpus.\n",
> --
> 2.31.1
>
>
