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Warn the user if the kernel driver dropped samples or ran out of event buffers

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during a data collection run.
This commit is contained in:
Joseph Koshy 2005-10-21 18:59:59 +00:00
parent b2dec35043
commit 7fbf3da209
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=151542
1 changed files with 27 additions and 2 deletions
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29
usr.sbin/pmcstat/pmcstat.c
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@ -344,7 +344,7 @@ main(int argc, char **argv)
{
double interval;
int option, npmc, ncpu;
int c, current_cpu, current_sampling_count;
int c, check_driver_stats, current_cpu, current_sampling_count;
int do_print, do_descendants;
int do_logproccsw, do_logprocexit;
int pipefd[2];
@ -353,12 +353,14 @@ main(int argc, char **argv)
char *end;
const char *errmsg;
enum pmcstat_state runstate;
struct pmc_driverstats ds_start, ds_end;
struct pmcstat_ev *ev;
struct sigaction sa;
struct kevent kev;
struct winsize ws;
struct stat sb;
check_driver_stats = 0;
current_cpu = 0;
current_sampling_count = DEFAULT_SAMPLE_COUNT;
do_descendants = 0;
@ -749,6 +751,10 @@ main(int argc, char **argv)
err(EX_OSERR, "ERROR: Cannot configure log file");
}
/* remember to check for driver errors if we are sampling or logging */
check_driver_stats = (args.pa_flags & FLAG_HAS_SAMPLING_PMCS) ||
(args.pa_flags & FLAG_HAS_OUTPUT_LOGFILE);
/*
* Allocate PMCs.
*/
@ -839,6 +845,9 @@ main(int argc, char **argv)
if (args.pa_flags & (FLAG_HAS_PID | FLAG_HAS_COMMANDLINE))
pmcstat_setup_process(&args);
if (check_driver_stats && pmc_get_driver_stats(&ds_start) < 0)
err(EX_OSERR, "ERROR: Cannot retrieve driver statistics");
/* start the pmcs */
pmcstat_start_pmcs(&args);
@ -956,5 +965,21 @@ main(int argc, char **argv)
pmcstat_cleanup(&args);
return 0;
/* check if the driver lost any samples or events */
if (check_driver_stats) {
if (pmc_get_driver_stats(&ds_end) < 0)
err(EX_OSERR, "ERROR: Cannot retrieve driver "
"statistics");
if (ds_start.pm_intr_bufferfull != ds_end.pm_intr_bufferfull)
warn("WARNING: some samples were dropped. Please "
"consider tuning the \"kern.hwpmc.nsamples\" "
"tunable.");
if (ds_start.pm_buffer_requests_failed !=
ds_end.pm_buffer_requests_failed)
warn("WARNING: some events were discarded. Please "
"consider tuning the \"kern.hwpmc.nbuffers\" "
"tunable.");
}
exit(EX_OK);
}