[tip: perf/core] perf header: Support CPU PMU capabilities
From: tip-bot2 for Kan Liang
Date: Wed Apr 22 2020 - 08:22:12 EST
The following commit has been merged into the perf/core branch of tip:
Commit-ID: 6f91ea283a1ed23e4a548ddd62db6deb2c707f82
Gitweb: https://git.kernel.org/tip/6f91ea283a1ed23e4a548ddd62db6deb2c707f82
Author: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
AuthorDate: Thu, 19 Mar 2020 13:25:02 -07:00
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitterDate: Sat, 18 Apr 2020 09:05:00 -03:00
perf header: Support CPU PMU capabilities
To stitch LBR call stack, the max LBR information is required. So the
CPU PMU capabilities information has to be stored in perf header.
Add a new feature HEADER_CPU_PMU_CAPS for CPU PMU capabilities.
Retrieve all CPU PMU capabilities, not just max LBR information.
Add variable max_branches to facilitate future usage.
Committer testing:
# ls -la /sys/devices/cpu/caps/
total 0
drwxr-xr-x. 2 root root 0 Apr 17 10:53 .
drwxr-xr-x. 6 root root 0 Apr 17 07:02 ..
-r--r--r--. 1 root root 4096 Apr 17 10:53 max_precise
#
# cat /sys/devices/cpu/caps/max_precise
0
# perf record sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.033 MB perf.data (7 samples) ]
#
# perf report --header-only | egrep 'cpu(desc|.*capabilities)'
# cpudesc : AMD Ryzen 5 3600X 6-Core Processor
# cpu pmu capabilities: max_precise=0
#
And then on an Intel machine:
$ ls -la /sys/devices/cpu/caps/
total 0
drwxr-xr-x. 2 root root 0 Apr 17 10:51 .
drwxr-xr-x. 6 root root 0 Apr 17 10:04 ..
-r--r--r--. 1 root root 4096 Apr 17 11:37 branches
-r--r--r--. 1 root root 4096 Apr 17 10:51 max_precise
-r--r--r--. 1 root root 4096 Apr 17 11:37 pmu_name
$ cat /sys/devices/cpu/caps/max_precise
3
$ cat /sys/devices/cpu/caps/branches
32
$ cat /sys/devices/cpu/caps/pmu_name
skylake
$ perf record sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.001 MB perf.data (8 samples) ]
$ perf report --header-only | egrep 'cpu(desc|.*capabilities)'
# cpudesc : Intel(R) Core(TM) i5-7500 CPU @ 3.40GHz
# cpu pmu capabilities: branches=32, max_precise=3, pmu_name=skylake
$
Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Pavel Gerasimov <pavel.gerasimov@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ravi Bangoria <ravi.bangoria@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Vitaly Slobodskoy <vitaly.slobodskoy@xxxxxxxxx>
Link: http://lore.kernel.org/lkml/20200319202517.23423-3-kan.liang@xxxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/Documentation/perf.data-file-format.txt | 16 ++-
tools/perf/util/env.h | 3 +-
tools/perf/util/header.c | 108 ++++++++++++-
tools/perf/util/header.h | 1 +-
4 files changed, 128 insertions(+)
diff --git a/tools/perf/Documentation/perf.data-file-format.txt b/tools/perf/Documentation/perf.data-file-format.txt
index b0152e1..b6472e4 100644
--- a/tools/perf/Documentation/perf.data-file-format.txt
+++ b/tools/perf/Documentation/perf.data-file-format.txt
@@ -373,6 +373,22 @@ struct {
Indicates that trace contains records of PERF_RECORD_COMPRESSED type
that have perf_events records in compressed form.
+ HEADER_CPU_PMU_CAPS = 28,
+
+ A list of cpu PMU capabilities. The format of data is as below.
+
+struct {
+ u32 nr_cpu_pmu_caps;
+ {
+ char name[];
+ char value[];
+ } [nr_cpu_pmu_caps]
+};
+
+
+Example:
+ cpu pmu capabilities: branches=32, max_precise=3, pmu_name=icelake
+
other bits are reserved and should ignored for now
HEADER_FEAT_BITS = 256,
diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
index 7632075..1ab2682 100644
--- a/tools/perf/util/env.h
+++ b/tools/perf/util/env.h
@@ -48,6 +48,7 @@ struct perf_env {
char *cpuid;
unsigned long long total_mem;
unsigned int msr_pmu_type;
+ unsigned int max_branches;
int nr_cmdline;
int nr_sibling_cores;
@@ -57,12 +58,14 @@ struct perf_env {
int nr_memory_nodes;
int nr_pmu_mappings;
int nr_groups;
+ int nr_cpu_pmu_caps;
char *cmdline;
const char **cmdline_argv;
char *sibling_cores;
char *sibling_dies;
char *sibling_threads;
char *pmu_mappings;
+ char *cpu_pmu_caps;
struct cpu_topology_map *cpu;
struct cpu_cache_level *caches;
int caches_cnt;
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index acbd046..28e82da 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1395,6 +1395,38 @@ static int write_compressed(struct feat_fd *ff __maybe_unused,
return do_write(ff, &(ff->ph->env.comp_mmap_len), sizeof(ff->ph->env.comp_mmap_len));
}
+static int write_cpu_pmu_caps(struct feat_fd *ff,
+ struct evlist *evlist __maybe_unused)
+{
+ struct perf_pmu *cpu_pmu = perf_pmu__find("cpu");
+ struct perf_pmu_caps *caps = NULL;
+ int nr_caps;
+ int ret;
+
+ if (!cpu_pmu)
+ return -ENOENT;
+
+ nr_caps = perf_pmu__caps_parse(cpu_pmu);
+ if (nr_caps < 0)
+ return nr_caps;
+
+ ret = do_write(ff, &nr_caps, sizeof(nr_caps));
+ if (ret < 0)
+ return ret;
+
+ list_for_each_entry(caps, &cpu_pmu->caps, list) {
+ ret = do_write_string(ff, caps->name);
+ if (ret < 0)
+ return ret;
+
+ ret = do_write_string(ff, caps->value);
+ if (ret < 0)
+ return ret;
+ }
+
+ return ret;
+}
+
static void print_hostname(struct feat_fd *ff, FILE *fp)
{
fprintf(fp, "# hostname : %s\n", ff->ph->env.hostname);
@@ -1809,6 +1841,27 @@ static void print_compressed(struct feat_fd *ff, FILE *fp)
ff->ph->env.comp_level, ff->ph->env.comp_ratio);
}
+static void print_cpu_pmu_caps(struct feat_fd *ff, FILE *fp)
+{
+ const char *delimiter = "# cpu pmu capabilities: ";
+ u32 nr_caps = ff->ph->env.nr_cpu_pmu_caps;
+ char *str;
+
+ if (!nr_caps) {
+ fprintf(fp, "# cpu pmu capabilities: not available\n");
+ return;
+ }
+
+ str = ff->ph->env.cpu_pmu_caps;
+ while (nr_caps--) {
+ fprintf(fp, "%s%s", delimiter, str);
+ delimiter = ", ";
+ str += strlen(str) + 1;
+ }
+
+ fprintf(fp, "\n");
+}
+
static void print_pmu_mappings(struct feat_fd *ff, FILE *fp)
{
const char *delimiter = "# pmu mappings: ";
@@ -2846,6 +2899,60 @@ static int process_compressed(struct feat_fd *ff,
return 0;
}
+static int process_cpu_pmu_caps(struct feat_fd *ff,
+ void *data __maybe_unused)
+{
+ char *name, *value;
+ struct strbuf sb;
+ u32 nr_caps;
+
+ if (do_read_u32(ff, &nr_caps))
+ return -1;
+
+ if (!nr_caps) {
+ pr_debug("cpu pmu capabilities not available\n");
+ return 0;
+ }
+
+ ff->ph->env.nr_cpu_pmu_caps = nr_caps;
+
+ if (strbuf_init(&sb, 128) < 0)
+ return -1;
+
+ while (nr_caps--) {
+ name = do_read_string(ff);
+ if (!name)
+ goto error;
+
+ value = do_read_string(ff);
+ if (!value)
+ goto free_name;
+
+ if (strbuf_addf(&sb, "%s=%s", name, value) < 0)
+ goto free_value;
+
+ /* include a NULL character at the end */
+ if (strbuf_add(&sb, "", 1) < 0)
+ goto free_value;
+
+ if (!strcmp(name, "branches"))
+ ff->ph->env.max_branches = atoi(value);
+
+ free(value);
+ free(name);
+ }
+ ff->ph->env.cpu_pmu_caps = strbuf_detach(&sb, NULL);
+ return 0;
+
+free_value:
+ free(value);
+free_name:
+ free(name);
+error:
+ strbuf_release(&sb);
+ return -1;
+}
+
#define FEAT_OPR(n, func, __full_only) \
[HEADER_##n] = { \
.name = __stringify(n), \
@@ -2903,6 +3010,7 @@ const struct perf_header_feature_ops feat_ops[HEADER_LAST_FEATURE] = {
FEAT_OPR(BPF_PROG_INFO, bpf_prog_info, false),
FEAT_OPR(BPF_BTF, bpf_btf, false),
FEAT_OPR(COMPRESSED, compressed, false),
+ FEAT_OPR(CPU_PMU_CAPS, cpu_pmu_caps, false),
};
struct header_print_data {
diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
index 840f95c..650bd1c 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -43,6 +43,7 @@ enum {
HEADER_BPF_PROG_INFO,
HEADER_BPF_BTF,
HEADER_COMPRESSED,
+ HEADER_CPU_PMU_CAPS,
HEADER_LAST_FEATURE,
HEADER_FEAT_BITS = 256,
};