This is a note to let you know that I've just added the patch titled
perf pmu: Unbreak perf record for arm/arm64 with events with explicit PMU
to the 4.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-pmu-unbreak-perf-record-for-arm-arm64-with-events-with-explicit-pmu.patch
and it can be found in the queue-4.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 66ec11919a0f96e936bb731fdbc2851316077d26 Mon Sep 17 00:00:00 2001
From: Mark Rutland <mark.rutland@xxxxxxx>
Date: Fri, 6 Oct 2017 19:38:22 +0100
Subject: perf pmu: Unbreak perf record for arm/arm64 with events with explicit PMU
From: Mark Rutland <mark.rutland@xxxxxxx>
commit 66ec11919a0f96e936bb731fdbc2851316077d26 upstream.
Currently, perf record is broken on arm/arm64 systems when the PMU is
specified explicitly as part of the event, e.g.
$ ./perf record -e armv8_cortex_a53/cpu_cycles/u true
In such cases, perf record fails to open events unless
perf_event_paranoid is set to -1, even if the PMU in question supports
mode exclusion. Further, even when perf_event_paranoid is toggled, no
samples are recorded.
This is an unintended side effect of commit:
e3ba76deef23064f ("perf tools: Force uncore events to system wide monitoring)
... which assumes that if a PMU has an associated cpu_map, it is an
uncore PMU, and forces events for such PMUs to be system-wide.
This is not true for arm/arm64 systems, which can have heterogeneous
CPUs. To account for this, multiple CPU PMUs are exposed, each with a
"cpus" field under sysfs, which the perf tool parses into a cpu_map. ARM
PMUs do not have a "cpumask" file, and only have a "cpus" file. For the
gory details as to why, see commit:
7e3fcffe95544010 ("perf pmu: Support alternative sysfs cpumask")
Given all of this, we can instead identify uncore PMUs by explicitly
checking for a "cpumask" file, and restore arm/arm64 PMU support back to
a working state. This patch does so, adding a new perf_pmu::is_uncore
field, and splitting the existing cpumask parsing so that it can be
reused.
Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Tested-by Will Deacon <will.deacon@xxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Fixes: e3ba76deef23064f ("perf tools: Force uncore events to system wide monitoring)
Link: http://lkml.kernel.org/r/1507315102-5942-1-git-send-email-mark.rutland@xxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/perf/util/parse-events.c | 9 +++---
tools/perf/util/pmu.c | 56 ++++++++++++++++++++++++++++++-----------
tools/perf/util/pmu.h | 1
3 files changed, 47 insertions(+), 19 deletions(-)
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -309,10 +309,11 @@ static char *get_config_name(struct list
static struct perf_evsel *
__add_event(struct list_head *list, int *idx,
struct perf_event_attr *attr,
- char *name, struct cpu_map *cpus,
+ char *name, struct perf_pmu *pmu,
struct list_head *config_terms)
{
struct perf_evsel *evsel;
+ struct cpu_map *cpus = pmu ? pmu->cpus : NULL;
event_attr_init(attr);
@@ -323,7 +324,7 @@ __add_event(struct list_head *list, int
(*idx)++;
evsel->cpus = cpu_map__get(cpus);
evsel->own_cpus = cpu_map__get(cpus);
- evsel->system_wide = !!cpus;
+ evsel->system_wide = pmu ? pmu->is_uncore : false;
if (name)
evsel->name = strdup(name);
@@ -1232,7 +1233,7 @@ int parse_events_add_pmu(struct parse_ev
if (!head_config) {
attr.type = pmu->type;
- evsel = __add_event(list, &data->idx, &attr, NULL, pmu->cpus, NULL);
+ evsel = __add_event(list, &data->idx, &attr, NULL, pmu, NULL);
return evsel ? 0 : -ENOMEM;
}
@@ -1253,7 +1254,7 @@ int parse_events_add_pmu(struct parse_ev
return -EINVAL;
evsel = __add_event(list, &data->idx, &attr,
- get_config_name(head_config), pmu->cpus,
+ get_config_name(head_config), pmu,
&config_terms);
if (evsel) {
evsel->unit = info.unit;
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -470,17 +470,36 @@ static void pmu_read_sysfs(void)
closedir(dir);
}
+static struct cpu_map *__pmu_cpumask(const char *path)
+{
+ FILE *file;
+ struct cpu_map *cpus;
+
+ file = fopen(path, "r");
+ if (!file)
+ return NULL;
+
+ cpus = cpu_map__read(file);
+ fclose(file);
+ return cpus;
+}
+
+/*
+ * Uncore PMUs have a "cpumask" file under sysfs. CPU PMUs (e.g. on arm/arm64)
+ * may have a "cpus" file.
+ */
+#define CPUS_TEMPLATE_UNCORE "%s/bus/event_source/devices/%s/cpumask"
+#define CPUS_TEMPLATE_CPU "%s/bus/event_source/devices/%s/cpus"
+
static struct cpu_map *pmu_cpumask(const char *name)
{
- struct stat st;
char path[PATH_MAX];
- FILE *file;
struct cpu_map *cpus;
const char *sysfs = sysfs__mountpoint();
const char *templates[] = {
- "%s/bus/event_source/devices/%s/cpumask",
- "%s/bus/event_source/devices/%s/cpus",
- NULL
+ CPUS_TEMPLATE_UNCORE,
+ CPUS_TEMPLATE_CPU,
+ NULL
};
const char **template;
@@ -489,20 +508,25 @@ static struct cpu_map *pmu_cpumask(const
for (template = templates; *template; template++) {
snprintf(path, PATH_MAX, *template, sysfs, name);
- if (stat(path, &st) == 0)
- break;
+ cpus = __pmu_cpumask(path);
+ if (cpus)
+ return cpus;
}
- if (!*template)
- return NULL;
+ return NULL;
+}
- file = fopen(path, "r");
- if (!file)
- return NULL;
+static bool pmu_is_uncore(const char *name)
+{
+ char path[PATH_MAX];
+ struct cpu_map *cpus;
+ const char *sysfs = sysfs__mountpoint();
- cpus = cpu_map__read(file);
- fclose(file);
- return cpus;
+ snprintf(path, PATH_MAX, CPUS_TEMPLATE_UNCORE, sysfs, name);
+ cpus = __pmu_cpumask(path);
+ cpu_map__put(cpus);
+
+ return !!cpus;
}
/*
@@ -617,6 +641,8 @@ static struct perf_pmu *pmu_lookup(const
pmu->cpus = pmu_cpumask(name);
+ pmu->is_uncore = pmu_is_uncore(name);
+
INIT_LIST_HEAD(&pmu->format);
INIT_LIST_HEAD(&pmu->aliases);
list_splice(&format, &pmu->format);
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -22,6 +22,7 @@ struct perf_pmu {
char *name;
__u32 type;
bool selectable;
+ bool is_uncore;
struct perf_event_attr *default_config;
struct cpu_map *cpus;
struct list_head format; /* HEAD struct perf_pmu_format -> list */
Patches currently in stable-queue which might be from mark.rutland@xxxxxxx are
queue-4.13/perf-pmu-unbreak-perf-record-for-arm-arm64-with-events-with-explicit-pmu.patch