Date: Thu, 16 Apr 2026 06:06:33 +0000 From: Warner Losh <imp@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Cc: Andre Silva <andasilv@amd.com> Subject: git: ee12645ec737 - main - pmcstat: print raw TSC in decoded log output Message-ID: <69e07c69.3cc0a.32f78fbf@gitrepo.freebsd.org>
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The branch main has been updated by imp: URL: https://cgit.FreeBSD.org/src/commit/?id=ee12645ec737eb940554769af2c275524ea20d37 commit ee12645ec737eb940554769af2c275524ea20d37 Author: Andre Silva <andasilv@amd.com> AuthorDate: 2026-03-31 20:28:39 +0000 Commit: Warner Losh <imp@FreeBSD.org> CommitDate: 2026-04-16 06:05:21 +0000 pmcstat: print raw TSC in decoded log output Extend pmcstat -R output to include the raw TSC for each decoded record and print tsc_freq from the initialize record so TSC deltas can be converted to elapsed time. Update the pmcstat documentation to describe the decoded output and the architecture-specific TSC behavior. Sponsored by: AMD Signed-off-by: Andre Silva <andasilv@amd.com> Reviewed by: imp, mhorne, Ali Mashtizadeh Pull Request: https://github.com/freebsd/freebsd-src/pull/2085 --- usr.sbin/pmcstat/pmcstat.8 | 26 +++++++++++++++++++++++++- usr.sbin/pmcstat/pmcstat.h | 5 +++-- usr.sbin/pmcstat/pmcstat_log.c | 8 ++++++-- 3 files changed, 34 insertions(+), 5 deletions(-) diff --git a/usr.sbin/pmcstat/pmcstat.8 b/usr.sbin/pmcstat/pmcstat.8 index edb9ff106092..c78a13f910f9 100644 --- a/usr.sbin/pmcstat/pmcstat.8 +++ b/usr.sbin/pmcstat/pmcstat.8 @@ -23,7 +23,7 @@ .\" out of the use of this software, even if advised of the possibility of .\" such damage. .\" -.Dd April 19, 2025 +.Dd April 15, 2026 .Dt PMCSTAT 8 .Os .Sh NAME @@ -220,6 +220,30 @@ specified in .It Fl R Ar logfilename Perform offline analysis using sampling data in file .Ar logfilename . +Each decoded record is printed as a single line with the following fields: +a record type (e.g., +.Dq callchain , +.Dq initlog ) , +type-specific data, and a trailing 20-digit raw TSC value recording the +CPU cycle at which the event occurred. +The +.Dq initlog +record additionally prints +.Dq Li tsc_freq=<hz> , +the TSC tick rate in Hz measured by the kernel at boot. +To convert a TSC delta to nanoseconds: +.Pp +.Dl elapsed_ns = (tsc_end - tsc_start) * 1e9 / tsc_freq +.Pp +TSC-based timestamps and +.Dq Li tsc_freq +are only meaningful on x86 architectures +.Pq amd64 and i386 . +On all other architectures +.Pq including arm64 and powerpc +the +.Dq Li tsc_freq +field will be zero. .It Fl S Ar event-spec Allocate a system mode sampling PMC measuring hardware events specified in diff --git a/usr.sbin/pmcstat/pmcstat.h b/usr.sbin/pmcstat/pmcstat.h index 67571ce4b2ee..6131d7a50404 100644 --- a/usr.sbin/pmcstat/pmcstat.h +++ b/usr.sbin/pmcstat/pmcstat.h @@ -50,8 +50,9 @@ #define PMCSTAT_PRINT_ENTRY(T,...) do { \ (void) fprintf(args.pa_printfile, "%-9s", T); \ - (void) fprintf(args.pa_printfile, " " __VA_ARGS__); \ - (void) fprintf(args.pa_printfile, "\n"); \ + (void) fprintf(args.pa_printfile, " " __VA_ARGS__); \ + (void) fprintf(args.pa_printfile, " %20ju\n", \ + (uintmax_t)_pmcstat_current_tsc); \ } while (0) #define PMCSTAT_PL_NONE 0 diff --git a/usr.sbin/pmcstat/pmcstat_log.c b/usr.sbin/pmcstat/pmcstat_log.c index db9cbfabd9da..9af2ccc4e365 100644 --- a/usr.sbin/pmcstat/pmcstat_log.c +++ b/usr.sbin/pmcstat/pmcstat_log.c @@ -194,6 +194,7 @@ static struct pmc_plugins plugins[] = { }; static int pmcstat_mergepmc; +static uint64_t _pmcstat_current_tsc; /* TSC for PMCSTAT_PRINT_ENTRY */ int pmcstat_pmcinfilter = 0; /* PMC filter for top mode. */ float pmcstat_threshold = 0.5; /* Cost filter for top mode. */ @@ -471,6 +472,7 @@ pmcstat_print_log(void) while (pmclog_read(args.pa_logparser, &ev) == 0) { assert(ev.pl_state == PMCLOG_OK); + _pmcstat_current_tsc = ev.pl_tsc; switch (ev.pl_type) { case PMCLOG_TYPE_CALLCHAIN: PMCSTAT_PRINT_ENTRY("callchain", @@ -496,9 +498,11 @@ pmcstat_print_log(void) PMCSTAT_PRINT_ENTRY("drop",); break; case PMCLOG_TYPE_INITIALIZE: - PMCSTAT_PRINT_ENTRY("initlog","0x%x \"%s\"", + PMCSTAT_PRINT_ENTRY("initlog", + "0x%x \"%s\" tsc_freq=%" PRIu64, ev.pl_u.pl_i.pl_version, - pmc_name_of_cputype(ev.pl_u.pl_i.pl_arch)); + pmc_name_of_cputype(ev.pl_u.pl_i.pl_arch), + ev.pl_u.pl_i.pl_tsc_freq); if ((ev.pl_u.pl_i.pl_version & 0xFF000000) != PMC_VERSION_MAJOR << 24) warnx(home | help
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