On Wed, 6 Dec 2023, Crystal Wood wrote:
> Add support for the --histogram and --histfile options as in cyclictest.
> The short -h option is not supported, as cyclicdeadline already uses that
> for help. -H/--histofall is not supported but could be easily added.
>
> Signed-off-by: Crystal Wood <crwood@xxxxxxxxxx>
> ---
> Given the recent request for oslat, do we want to be able to do ns-granularity
> histograms? Or just stick with what cyclictest supports, as that's what rteval
> wants?
rteval will want what we teach it to want. If the hardware supports
meaningful numbers with ns-granularity, it might make sense to include it.
start with just doing what cyclictest currently supports, but I wouldn't
rule out adding this in the future.
>
> Is histofall support needed? rteval doesn't use it.
Not sure, we probably want one or the other, I suppose the idea was to not
have the extra information if you're parsing it with another program like
rteval but to include it otherwise. I ran it just ctrl-cing it and
couldn't see a difference.
John
> ---
> src/sched_deadline/cyclicdeadline.c | 113 +++++++++++++++++++++++++---
> 1 file changed, 103 insertions(+), 10 deletions(-)
>
> diff --git a/src/sched_deadline/cyclicdeadline.c b/src/sched_deadline/cyclicdeadline.c
> index 097e2e5d4580..f45ec3d6394b 100644
> --- a/src/sched_deadline/cyclicdeadline.c
> +++ b/src/sched_deadline/cyclicdeadline.c
> @@ -33,6 +33,7 @@
> #include "rt-utils.h"
> #include "rt-sched.h"
> #include "rt-error.h"
> +#include "histogram.h"
>
> #define _STR(x) #x
> #define STR(x) _STR(x)
> @@ -40,6 +41,8 @@
> #define MAXPATH 1024
> #endif
>
> +#define HIST_MAX 1000000
> +
> #define CPUSET_ALL "my_cpuset_all"
> #define CPUSET_LOCAL "my_cpuset"
>
> @@ -56,16 +59,13 @@ struct thread_stat {
> long act;
> double avg;
> long *values;
> - long *hist_array;
> - long *outliers;
> + struct histogram *hist;
> pthread_t thread;
> int threadstarted;
> int tid;
> long reduce;
> long redmax;
> long cycleofmax;
> - long hist_overflow;
> - long num_outliers;
> };
>
> struct sched_data {
> @@ -84,6 +84,8 @@ static int info_enable;
> static int debug_enable;
> static int tracelimit;
> static int trace_marker;
> +static int histogram;
> +static FILE *histfile;
> static pthread_mutex_t break_thread_id_lock = PTHREAD_MUTEX_INITIALIZER;
> static pid_t break_thread_id;
> static uint64_t break_thread_value;
> @@ -97,6 +99,8 @@ static int mark_fd;
> static int quiet;
> static char jsonfile[MAX_PATH];
>
> +static struct histoset hset;
> +
> static int find_mount(const char *mount, char *debugfs)
> {
> char type[100];
> @@ -691,6 +695,10 @@ static void usage(int error)
> " Append 'm', 'h', or 'd' to specify minutes, hours or\n"
> " days\n"
> "-h --help Show this help menu.\n"
> + " --histogram=US dump a latency histogram to stdout after the run\n"
> + " US is the max latency time to be tracked in microseconds\n"
> + " This option runs all threads at the same priority.\n"
> + " --histfile=<path> dump the latency histogram to <path> instead of stdout\n"
> "-i INTV --interval The shortest deadline for the tasks in us\n"
> " (default 1000us).\n"
> " --json=FILENAME write final results into FILENAME, JSON formatted\n"
> @@ -718,6 +726,55 @@ static u64 get_time_us(void)
> return time;
> }
>
> +static void print_hist(FILE *fp, struct sched_data *sd, int nthreads)
> +{
> + int i;
> + unsigned long maxmax, alloverflows;
> +
> + fprintf(fp, "# Histogram\n");
> + for (i = 0; i < histogram; i++) {
> + unsigned long flags = 0;
> +
> + fprintf(fp, "%06d ", i);
> +
> + hset_print_bucket(&hset, fp, i, flags);
> + fprintf(fp, "\n");
> + }
> + fprintf(fp, "# Min Latencies:");
> + for (i = 0; i < nthreads; i++)
> + fprintf(fp, " %05lu", sd[i].stat.min);
> + fprintf(fp, "\n");
> + fprintf(fp, "# Avg Latencies:");
> + for (i = 0; i < nthreads; i++)
> + fprintf(fp, " %05lu", sd[i].stat.cycles ?
> + (long)(sd[i].stat.avg/sd[i].stat.cycles) : 0);
> + fprintf(fp, "\n");
> + fprintf(fp, "# Max Latencies:");
> + maxmax = 0;
> + for (i = 0; i < nthreads; i++) {
> + fprintf(fp, " %05lu", sd[i].stat.max);
> + if (sd[i].stat.max > maxmax)
> + maxmax = sd[i].stat.max;
> + }
> + fprintf(fp, "\n");
> + fprintf(fp, "# Histogram Overflows:");
> + alloverflows = 0;
> + for (i = 0; i < nthreads; i++) {
> + fprintf(fp, " %05lu", sd[i].stat.hist->oflow_count);
> + alloverflows += sd[i].stat.hist->oflow_count;
> + }
> + fprintf(fp, "\n");
> +
> + fprintf(fp, "# Histogram Overflow at cycle number:\n");
> + for (i = 0; i < nthreads; i++) {
> + fprintf(fp, "# Thread %d: ", i);
> + hist_print_oflows(sd[i].stat.hist, fp);
> + fprintf(fp, "\n");
> + }
> +
> + fprintf(fp, "\n");
> +}
> +
> static void print_stat(FILE *fp, struct sched_data *sd, int index, int verbose, int quiet)
> {
> struct thread_stat *stat = &sd->stat;
> @@ -784,6 +841,9 @@ static u64 do_runtime(struct sched_data *sd, u64 period)
> stat->act = diff;
> stat->avg += (double) diff;
>
> + if (histogram)
> + hist_sample(stat->hist, diff);
> +
> stat->cycles++;
>
> return next_period;
> @@ -1058,8 +1118,13 @@ static void loop(struct sched_data *sched_data, int nr_threads)
> if (!quiet) {
> printf("\033[%dB", nr_threads + 2);
> } else {
> - for (i = 0; i < nr_threads; ++i)
> - print_stat(stdout, &sched_data[i], i, 0, 0);
> + if (histogram) {
> + FILE *out = histfile ? histfile : stdout;
> + print_hist(out, sched_data, nr_threads);
> + } else {
> + for (i = 0; i < nr_threads; ++i)
> + print_stat(stdout, &sched_data[i], i, 0, 0);
> + }
> }
> }
>
> @@ -1075,10 +1140,14 @@ static void write_stats(FILE *f, void *data)
> for (i = 0; i < nr_threads; i++) {
> s = &sd[i].stat;
> fprintf(f, " \"%u\": {\n", i);
> - fprintf(f, " \"cycles\": %ld,\n", s->cycles);
> - fprintf(f, " \"min\": %ld,\n", s->min);
> - fprintf(f, " \"max\": %ld,\n", s->max);
> - fprintf(f, " \"avg\": %.2f\n", s->avg/s->cycles);
> +
> + fprintf(f, " \"histogram\": {");
> + hist_print_json(s->hist, f);
> + fprintf(f, " },\n");
> + fprintf(f, " \"cycles\": %ld,\n", s->cycles);
> + fprintf(f, " \"min\": %ld,\n", s->min);
> + fprintf(f, " \"max\": %ld,\n", s->max);
> + fprintf(f, " \"avg\": %.2f\n", s->avg/s->cycles);
> fprintf(f, " }%s\n", i == nr_threads - 1 ? "" : ",");
> }
> fprintf(f, " }\n");
> @@ -1088,6 +1157,7 @@ enum options_values {
> OPT_AFFINITY=1, OPT_DURATION, OPT_HELP, OPT_INTERVAL,
> OPT_JSON, OPT_STEP, OPT_THREADS, OPT_QUIET,
> OPT_BREAKTRACE, OPT_TRACEMARK, OPT_INFO, OPT_DEBUG,
> + OPT_HISTOGRAM, OPT_HISTFILE
> };
>
> int main(int argc, char **argv)
> @@ -1130,6 +1200,8 @@ int main(int argc, char **argv)
> { "tracemark", no_argument, NULL, OPT_TRACEMARK },
> { "verbose", no_argument, NULL, OPT_INFO},
> { "debug", no_argument, NULL, OPT_DEBUG},
> + { "histogram", required_argument, NULL, OPT_HISTOGRAM },
> + { "histfile", required_argument, NULL, OPT_HISTFILE },
> { NULL, 0, NULL, 0 },
> };
> c = getopt_long(argc, argv, "a::c:D:hi:s:t:b:q", options, NULL);
> @@ -1188,6 +1260,17 @@ int main(int argc, char **argv)
> case OPT_DEBUG:
> debug_enable = 1;
> break;
> + case OPT_HISTOGRAM:
> + histogram = atoi(optarg);
> + if (histogram <= 0 || histogram > HIST_MAX)
> + usage(1);
> + break;
> + case OPT_HISTFILE:
> + histfile = fopen(optarg, "w");
> + if (!histfile)
> + fatal("Couldn\'t open histfile %s: %s\n",
> + optarg, strerror(errno));
> + break;
> default:
> usage(1);
> }
> @@ -1233,6 +1316,10 @@ int main(int argc, char **argv)
> if (!thread || !sched_data)
> fatal("allocating threads");
>
> + if (histogram && hset_init(&hset, nr_threads, 1, histogram, histogram))
> + fatal("failed to allocate histogram of size %d for %d threads\n",
> + histogram, nr_threads);
> +
> if (nr_threads > nr_cpus) {
> /*
> * More threads than CPUs, then have the total be
> @@ -1262,6 +1349,9 @@ int main(int argc, char **argv)
> sd->runtime_us = runtime;
> sd->deadline_us = interval;
>
> + if (histogram)
> + sd->stat.hist = &hset.histos[i];
> +
> info(info_enable, "interval: %lld:%lld\n", sd->runtime_us, sd->deadline_us);
>
> /* Make sure that we can make our deadlines */
> @@ -1356,6 +1446,9 @@ int main(int argc, char **argv)
> free(setcpu_buf);
> free(thread);
> free(sched_data);
> + if (histfile)
> + fclose(histfile);
> + hset_destroy(&hset);
>
> return 0;
> }
> --
> 2.43.0
>
>
>
