Commit 6f91ea28 authored by Kan Liang's avatar Kan Liang Committed by Arnaldo Carvalho de Melo
Browse files

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: default avatarKan Liang <kan.liang@linux.intel.com>
Reviewed-by: default avatarAndi Kleen <ak@linux.intel.com>
Acked-by: default avatarJiri Olsa <jolsa@redhat.com>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Pavel Gerasimov <pavel.gerasimov@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vitaly Slobodskoy <vitaly.slobodskoy@intel.com>
Link: http://lore.kernel.org/lkml/20200319202517.23423-3-kan.liang@linux.intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 3a6c51e4

tools/perf/Documentation/perf.data-file-format.txt

+16 −0
Original line number Diff line number Diff line
@@ -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,

tools/perf/util/env.h

+3 −0
Original line number Diff line number Diff line
@@ -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;

tools/perf/util/header.c

+108 −0
Original line number Diff line number Diff line
@@ -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 {

tools/perf/util/header.h

+1 −0
Original line number Diff line number Diff line
@@ -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,

};