4.16-stable review patch. If anyone has any objections, please let me know.
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From: Kan Liang kan.liang@linux.intel.com
[ Upstream commit 292c34c10249c64a70def442f0d977bf9d466ed7 ]
When counting uncore event with alias, core event is mistakenly involved, for example:
perf stat --no-merge -e "unc_m_cas_count.all" -C0 sleep 1
Performance counter stats for 'CPU(s) 0':
0 unc_m_cas_count.all [uncore_imc_4] 0 unc_m_cas_count.all [uncore_imc_2] 0 unc_m_cas_count.all [uncore_imc_0] 153,640 unc_m_cas_count.all [cpu] 0 unc_m_cas_count.all [uncore_imc_5] 25,026 unc_m_cas_count.all [uncore_imc_3] 0 unc_m_cas_count.all [uncore_imc_1]
1.001447890 seconds time elapsed
The reason is that current implementation doesn't check PMU name of a event when adding its alias into the alias list for core PMU. The uncore event aliases are mistakenly added.
This bug was introduced in: commit 14b22ae028de ("perf pmu: Add helper function is_pmu_core to detect PMU CORE devices")
Checking the PMU name for all PMUs on X86 and other architectures except ARM. There is no behavior change for ARM.
Signed-off-by: Kan Liang kan.liang@linux.intel.com Tested-by: Arnaldo Carvalho de Melo acme@redhat.com Cc: Agustin Vega-Frias agustinv@codeaurora.org Cc: Andi Kleen ak@linux.intel.com Cc: Ganapatrao Kulkarni ganapatrao.kulkarni@cavium.com Cc: Jin Yao yao.jin@linux.intel.com Cc: Jiri Olsa jolsa@redhat.com Cc: Namhyung Kim namhyung@kernel.org Cc: Peter Zijlstra peterz@infradead.org Cc: Shaokun Zhang zhangshaokun@hisilicon.com Cc: Will Deacon will.deacon@arm.com Fixes: 14b22ae028de ("perf pmu: Add helper function is_pmu_core to detect PMU CORE devices") Link: http://lkml.kernel.org/r/1524594014-79243-1-git-send-email-kan.liang@linux.i... Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/perf/util/pmu.c | 20 +++++++------------- 1 file changed, 7 insertions(+), 13 deletions(-)
--- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -539,9 +539,10 @@ static bool pmu_is_uncore(const char *na
/* * PMU CORE devices have different name other than cpu in sysfs on some - * platforms. looking for possible sysfs files to identify as core device. + * platforms. + * Looking for possible sysfs files to identify the arm core device. */ -static int is_pmu_core(const char *name) +static int is_arm_pmu_core(const char *name) { struct stat st; char path[PATH_MAX]; @@ -550,12 +551,6 @@ static int is_pmu_core(const char *name) if (!sysfs) return 0;
- /* Look for cpu sysfs (x86 and others) */ - scnprintf(path, PATH_MAX, "%s/bus/event_source/devices/cpu", sysfs); - if ((stat(path, &st) == 0) && - (strncmp(name, "cpu", strlen("cpu")) == 0)) - return 1; - /* Look for cpu sysfs (specific to arm) */ scnprintf(path, PATH_MAX, "%s/bus/event_source/devices/%s/cpus", sysfs, name); @@ -651,6 +646,7 @@ static void pmu_add_cpu_aliases(struct l struct pmu_events_map *map; struct pmu_event *pe; const char *name = pmu->name; + const char *pname;
map = perf_pmu__find_map(pmu); if (!map) @@ -669,11 +665,9 @@ static void pmu_add_cpu_aliases(struct l break; }
- if (!is_pmu_core(name)) { - /* check for uncore devices */ - if (pe->pmu == NULL) - continue; - if (strncmp(pe->pmu, name, strlen(pe->pmu))) + if (!is_arm_pmu_core(name)) { + pname = pe->pmu ? pe->pmu : "cpu"; + if (strncmp(pname, name, strlen(pname))) continue; }