mirrors/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2025-11-04 02:30:34 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

perf pmu: Fix core PMU alias list for X86 platform

Browse source 
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 14b22ae028 ("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: 14b22ae028 ("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.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Kan Liang 2018-04-24 11:20:10 -07:00 committed by Arnaldo Carvalho de Melo
parent 5d9946c3e5
commit 292c34c102
1 changed files with 7 additions and 13 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

20
tools/perf/util/pmu.c
View file

@ -539,9 +539,10 @@ static bool pmu_is_uncore(const char *name)
/* /*
* PMU CORE devices have different name other than cpu in sysfs on some * 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; struct stat st;
char path[PATH_MAX]; char path[PATH_MAX];
@ -550,12 +551,6 @@ static int is_pmu_core(const char *name)
if (!sysfs) if (!sysfs)
return 0; 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) */ /* Look for cpu sysfs (specific to arm) */
scnprintf(path, PATH_MAX, "%s/bus/event_source/devices/%s/cpus", scnprintf(path, PATH_MAX, "%s/bus/event_source/devices/%s/cpus",
sysfs, name); sysfs, name);
@ -668,6 +663,7 @@ static void pmu_add_cpu_aliases(struct list_head *head, struct perf_pmu *pmu)
struct pmu_events_map *map; struct pmu_events_map *map;
struct pmu_event *pe; struct pmu_event *pe;
const char *name = pmu->name; const char *name = pmu->name;
const char *pname;
map = perf_pmu__find_map(pmu); map = perf_pmu__find_map(pmu);
if (!map) if (!map)
@ -686,11 +682,9 @@ static void pmu_add_cpu_aliases(struct list_head *head, struct perf_pmu *pmu)
break; break;
} }
if (!is_pmu_core(name)) { if (!is_arm_pmu_core(name)) {
/* check for uncore devices */ pname = pe->pmu ? pe->pmu : "cpu";
if (pe->pmu == NULL) if (strncmp(pname, name, strlen(pname)))
continue;
if (strncmp(pe->pmu, name, strlen(pe->pmu)))
continue; continue;
} }