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authorMitchell Horne <mhorne@FreeBSD.org>2021-05-13 18:57:37 +0000
committerMitchell Horne <mhorne@FreeBSD.org>2021-07-29 15:01:09 +0000
commitdfb4fb41166bc35935e5f6fd9351a0ada0f71159 (patch)
treeddbde9a8d62054e5ee59b2e12219672e6f920ae8
parent57caeb5109ee3f385fbabb667eca9588588bcc52 (diff)
downloadsrc-dfb4fb41166bc35935e5f6fd9351a0ada0f71159.tar.gz
src-dfb4fb41166bc35935e5f6fd9351a0ada0f71159.zip
libpmc: fall-back to kernel tables if pmu-events fails
On x86, the pmu_events table is the source of truth for finding supported events. However, events not found there may still be present in the kernel's static event tables. For example, the pmc.soft(3) events will never be available from pmu-events. Update pmc_allocate() to search the legacy event tables if pmc_pmu_pmcallocate() fails to return a result. This allows both event sources to be consulted before giving up, thus restoring pmc.soft(3) and pmc.tsc(3) on x86. Reviewed by: emaste MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D30216 (cherry picked from commit dfdc57e8aa8ba4b4e4484f736e8c7645ab69b54a)
-rw-r--r--lib/libpmc/libpmc.c40
1 files changed, 19 insertions, 21 deletions
diff --git a/lib/libpmc/libpmc.c b/lib/libpmc/libpmc.c
index 6636c974cb73..e2422f167267 100644
--- a/lib/libpmc/libpmc.c
+++ b/lib/libpmc/libpmc.c
@@ -989,25 +989,25 @@ pmc_allocate(const char *ctrspec, enum pmc_mode mode,
pmc_config.pm_count = count;
if (PMC_IS_SAMPLING_MODE(mode))
pmc_config.pm_caps |= PMC_CAP_INTERRUPT;
+
/*
- * Can we pull this straight from the pmu table?
+ * Try to pull the raw event ID directly from the pmu-events table. If
+ * this is unsupported on the platform, or the event is not found,
+ * continue with searching the regular event tables.
*/
r = spec_copy = strdup(ctrspec);
ctrname = strsep(&r, ",");
if (pmc_pmu_enabled()) {
- if (pmc_pmu_pmcallocate(ctrname, &pmc_config) == 0) {
- if (PMC_CALL(PMCALLOCATE, &pmc_config) < 0) {
- goto out;
- }
- retval = 0;
- *pmcid = pmc_config.pm_pmcid;
- goto out;
- }
- errx(EX_USAGE, "ERROR: pmc_pmu_allocate failed, check for ctrname %s\n", ctrname);
- } else {
- free(spec_copy);
- spec_copy = NULL;
+ if (pmc_pmu_pmcallocate(ctrname, &pmc_config) == 0)
+ goto found;
+
+ /* Otherwise, reset any changes */
+ pmc_config.pm_ev = 0;
+ pmc_config.pm_caps = 0;
+ pmc_config.pm_class = 0;
}
+ free(spec_copy);
+ spec_copy = NULL;
/* replace an event alias with the canonical event specifier */
if (pmc_mdep_event_aliases)
@@ -1064,14 +1064,12 @@ pmc_allocate(const char *ctrspec, enum pmc_mode mode,
goto out;
}
- if (PMC_CALL(PMCALLOCATE, &pmc_config) < 0)
- goto out;
-
- *pmcid = pmc_config.pm_pmcid;
-
- retval = 0;
-
- out:
+found:
+ if (PMC_CALL(PMCALLOCATE, &pmc_config) == 0) {
+ *pmcid = pmc_config.pm_pmcid;
+ retval = 0;
+ }
+out:
if (spec_copy)
free(spec_copy);