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Subject[tip:perf/core] perf stat: Add no-aggregation mode to -a
Commit-ID:  f5b4a9c3ab53d544a540a6f3a5d17184e374d91a
Gitweb: http://git.kernel.org/tip/f5b4a9c3ab53d544a540a6f3a5d17184e374d91a
Author: Stephane Eranian <eranian@google.com>
AuthorDate: Tue, 16 Nov 2010 11:05:01 +0200
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 19 Nov 2010 16:16:53 -0200

perf stat: Add no-aggregation mode to -a

This patch adds a new -A option to perf stat. If specified then perf stat does
not aggregate counts across all monitored CPUs in system-wide mode, i.e., when
using -a. This option is not supported in per-thread mode.

Being able to get a per-cpu breakdown is useful to detect imbalances between
CPUs when running a uniform workload than spans all monitored CPUs.

The second version corrects the missing cpumap[] support, so that it works when
the -C option is used.

The third version fixes a missing cpumap[] in print_counter() and removes a
stray patch in builtin-trace.c.

Examples on a 4-way system:

# perf stat -a -e cycles,instructions -- sleep 1
Performance counter stats for 'sleep 1':
9592808135 cycles
3490380006 instructions # 0.364 IPC
1.001584632 seconds time elapsed

# perf stat -a -A -e cycles,instructions -- sleep 1
Performance counter stats for 'sleep 1':
CPU0 2398163767 cycles
CPU1 2398180817 cycles
CPU2 2398217115 cycles
CPU3 2398247483 cycles
CPU0 872282046 instructions # 0.364 IPC
CPU1 873481776 instructions # 0.364 IPC
CPU2 872638127 instructions # 0.364 IPC
CPU3 872437789 instructions # 0.364 IPC
1.001556052 seconds time elapsed

Cc: David S. Miller <davem@davemloft.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Richter <robert.richter@amd.com>
LKML-Reference: <4ce257b5.1e07e30a.7b6b.3aa9@mx.google.com>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/Documentation/perf-stat.txt | 5 +
tools/perf/builtin-stat.c | 169 +++++++++++++++++++++++++++-----
2 files changed, 149 insertions(+), 25 deletions(-)

diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
index 4b3a2d4..c405bca 100644
--- a/tools/perf/Documentation/perf-stat.txt
+++ b/tools/perf/Documentation/perf-stat.txt
@@ -53,6 +53,11 @@ comma-sperated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2
In per-thread mode, this option is ignored. The -a option is still necessary
to activate system-wide monitoring. Default is to count on all CPUs.

+-A::
+--no-aggr::
+Do not aggregate counts across all monitored CPUs in system-wide mode (-a).
+This option is only valid in system-wide mode.
+
EXAMPLES
--------

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index a6b4d44..b3e568f 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -75,6 +75,7 @@ static int run_idx = 0;
static int run_count = 1;
static bool no_inherit = false;
static bool scale = true;
+static bool no_aggr = false;
static pid_t target_pid = -1;
static pid_t target_tid = -1;
static pid_t *all_tids = NULL;
@@ -89,6 +90,12 @@ static int *fd[MAX_NR_CPUS][MAX_COUNTERS];

static int event_scaled[MAX_COUNTERS];

+static struct {
+ u64 val;
+ u64 ena;
+ u64 run;
+} cpu_counts[MAX_NR_CPUS][MAX_COUNTERS];
+
static volatile int done = 0;

struct stats
@@ -136,10 +143,10 @@ static double stddev_stats(struct stats *stats)
}

struct stats event_res_stats[MAX_COUNTERS][3];
-struct stats runtime_nsecs_stats;
+struct stats runtime_nsecs_stats[MAX_NR_CPUS];
+struct stats runtime_cycles_stats[MAX_NR_CPUS];
+struct stats runtime_branches_stats[MAX_NR_CPUS];
struct stats walltime_nsecs_stats;
-struct stats runtime_cycles_stats;
-struct stats runtime_branches_stats;

#define MATCH_EVENT(t, c, counter) \
(attrs[counter].type == PERF_TYPE_##t && \
@@ -205,8 +212,9 @@ static inline int nsec_counter(int counter)

/*
* Read out the results of a single counter:
+ * aggregate counts across CPUs in system-wide mode
*/
-static void read_counter(int counter)
+static void read_counter_aggr(int counter)
{
u64 count[3], single_count[3];
int cpu;
@@ -264,11 +272,58 @@ static void read_counter(int counter)
* Save the full runtime - to allow normalization during printout:
*/
if (MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter))
- update_stats(&runtime_nsecs_stats, count[0]);
+ update_stats(&runtime_nsecs_stats[0], count[0]);
if (MATCH_EVENT(HARDWARE, HW_CPU_CYCLES, counter))
- update_stats(&runtime_cycles_stats, count[0]);
+ update_stats(&runtime_cycles_stats[0], count[0]);
if (MATCH_EVENT(HARDWARE, HW_BRANCH_INSTRUCTIONS, counter))
- update_stats(&runtime_branches_stats, count[0]);
+ update_stats(&runtime_branches_stats[0], count[0]);
+}
+
+/*
+ * Read out the results of a single counter:
+ * do not aggregate counts across CPUs in system-wide mode
+ */
+static void read_counter(int counter)
+{
+ u64 count[3];
+ int cpu;
+ size_t res, nv;
+
+ count[0] = count[1] = count[2] = 0;
+
+ nv = scale ? 3 : 1;
+
+ for (cpu = 0; cpu < nr_cpus; cpu++) {
+
+ if (fd[cpu][counter][0] < 0)
+ continue;
+
+ res = read(fd[cpu][counter][0], count, nv * sizeof(u64));
+
+ assert(res == nv * sizeof(u64));
+
+ close(fd[cpu][counter][0]);
+ fd[cpu][counter][0] = -1;
+
+ if (scale) {
+ if (count[2] == 0) {
+ count[0] = 0;
+ } else if (count[2] < count[1]) {
+ count[0] = (unsigned long long)
+ ((double)count[0] * count[1] / count[2] + 0.5);
+ }
+ }
+ cpu_counts[cpu][counter].val = count[0]; /* scaled count */
+ cpu_counts[cpu][counter].ena = count[1];
+ cpu_counts[cpu][counter].run = count[2];
+
+ if (MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter))
+ update_stats(&runtime_nsecs_stats[cpu], count[0]);
+ if (MATCH_EVENT(HARDWARE, HW_CPU_CYCLES, counter))
+ update_stats(&runtime_cycles_stats[cpu], count[0]);
+ if (MATCH_EVENT(HARDWARE, HW_BRANCH_INSTRUCTIONS, counter))
+ update_stats(&runtime_branches_stats[cpu], count[0]);
+ }
}

static int run_perf_stat(int argc __used, const char **argv)
@@ -362,9 +417,13 @@ static int run_perf_stat(int argc __used, const char **argv)

update_stats(&walltime_nsecs_stats, t1 - t0);

- for (counter = 0; counter < nr_counters; counter++)
- read_counter(counter);
-
+ if (no_aggr) {
+ for (counter = 0; counter < nr_counters; counter++)
+ read_counter(counter);
+ } else {
+ for (counter = 0; counter < nr_counters; counter++)
+ read_counter_aggr(counter);
+ }
return WEXITSTATUS(status);
}

@@ -377,11 +436,15 @@ static void print_noise(int counter, double avg)
100 * stddev_stats(&event_res_stats[counter][0]) / avg);
}

-static void nsec_printout(int counter, double avg)
+static void nsec_printout(int cpu, int counter, double avg)
{
double msecs = avg / 1e6;

- fprintf(stderr, " %18.6f %-24s", msecs, event_name(counter));
+ if (no_aggr)
+ fprintf(stderr, "CPU%-4d %18.6f %-24s",
+ cpumap[cpu], msecs, event_name(counter));
+ else
+ fprintf(stderr, " %18.6f %-24s", msecs, event_name(counter));

if (MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter)) {
fprintf(stderr, " # %10.3f CPUs ",
@@ -389,33 +452,41 @@ static void nsec_printout(int counter, double avg)
}
}

-static void abs_printout(int counter, double avg)
+static void abs_printout(int cpu, int counter, double avg)
{
double total, ratio = 0.0;
+ char cpustr[16] = { '\0', };
+
+ if (no_aggr)
+ sprintf(cpustr, "CPU%-4d", cpumap[cpu]);
+ else
+ cpu = 0;

if (big_num)
- fprintf(stderr, " %'18.0f %-24s", avg, event_name(counter));
+ fprintf(stderr, "%s %'18.0f %-24s",
+ cpustr, avg, event_name(counter));
else
- fprintf(stderr, " %18.0f %-24s", avg, event_name(counter));
+ fprintf(stderr, "%s %18.0f %-24s",
+ cpustr, avg, event_name(counter));

if (MATCH_EVENT(HARDWARE, HW_INSTRUCTIONS, counter)) {
- total = avg_stats(&runtime_cycles_stats);
+ total = avg_stats(&runtime_cycles_stats[cpu]);

if (total)
ratio = avg / total;

fprintf(stderr, " # %10.3f IPC ", ratio);
} else if (MATCH_EVENT(HARDWARE, HW_BRANCH_MISSES, counter) &&
- runtime_branches_stats.n != 0) {
- total = avg_stats(&runtime_branches_stats);
+ runtime_branches_stats[cpu].n != 0) {
+ total = avg_stats(&runtime_branches_stats[cpu]);

if (total)
ratio = avg * 100 / total;

fprintf(stderr, " # %10.3f %% ", ratio);

- } else if (runtime_nsecs_stats.n != 0) {
- total = avg_stats(&runtime_nsecs_stats);
+ } else if (runtime_nsecs_stats[cpu].n != 0) {
+ total = avg_stats(&runtime_nsecs_stats[cpu]);

if (total)
ratio = 1000.0 * avg / total;
@@ -426,8 +497,9 @@ static void abs_printout(int counter, double avg)

/*
* Print out the results of a single counter:
+ * aggregated counts in system-wide mode
*/
-static void print_counter(int counter)
+static void print_counter_aggr(int counter)
{
double avg = avg_stats(&event_res_stats[counter][0]);
int scaled = event_scaled[counter];
@@ -439,9 +511,9 @@ static void print_counter(int counter)
}

if (nsec_counter(counter))
- nsec_printout(counter, avg);
+ nsec_printout(-1, counter, avg);
else
- abs_printout(counter, avg);
+ abs_printout(-1, counter, avg);

print_noise(counter, avg);

@@ -458,6 +530,42 @@ static void print_counter(int counter)
fprintf(stderr, "\n");
}

+/*
+ * Print out the results of a single counter:
+ * does not use aggregated count in system-wide
+ */
+static void print_counter(int counter)
+{
+ u64 ena, run, val;
+ int cpu;
+
+ for (cpu = 0; cpu < nr_cpus; cpu++) {
+ val = cpu_counts[cpu][counter].val;
+ ena = cpu_counts[cpu][counter].ena;
+ run = cpu_counts[cpu][counter].run;
+ if (run == 0 || ena == 0) {
+ fprintf(stderr, "CPU%-4d %18s %-24s", cpumap[cpu],
+ "<not counted>", event_name(counter));
+
+ fprintf(stderr, "\n");
+ continue;
+ }
+
+ if (nsec_counter(counter))
+ nsec_printout(cpu, counter, val);
+ else
+ abs_printout(cpu, counter, val);
+
+ print_noise(counter, 1.0);
+
+ if (run != ena) {
+ fprintf(stderr, " (scaled from %.2f%%)",
+ 100.0 * run / ena);
+ }
+ fprintf(stderr, "\n");
+ }
+}
+
static void print_stat(int argc, const char **argv)
{
int i, counter;
@@ -480,8 +588,13 @@ static void print_stat(int argc, const char **argv)
fprintf(stderr, " (%d runs)", run_count);
fprintf(stderr, ":\n\n");

- for (counter = 0; counter < nr_counters; counter++)
- print_counter(counter);
+ if (no_aggr) {
+ for (counter = 0; counter < nr_counters; counter++)
+ print_counter(counter);
+ } else {
+ for (counter = 0; counter < nr_counters; counter++)
+ print_counter_aggr(counter);
+ }

fprintf(stderr, "\n");
fprintf(stderr, " %18.9f seconds time elapsed",
@@ -545,6 +658,8 @@ static const struct option options[] = {
"print large numbers with thousands\' separators"),
OPT_STRING('C', "cpu", &cpu_list, "cpu",
"list of cpus to monitor in system-wide"),
+ OPT_BOOLEAN('A', "no-aggr", &no_aggr,
+ "disable CPU count aggregation"),
OPT_END()
};

@@ -562,6 +677,10 @@ int cmd_stat(int argc, const char **argv, const char *prefix __used)
if (run_count <= 0)
usage_with_options(stat_usage, options);

+ /* no_aggr is for system-wide only */
+ if (no_aggr && !system_wide)
+ usage_with_options(stat_usage, options);
+
/* Set attrs and nr_counters if no event is selected and !null_run */
if (!null_run && !nr_counters) {
memcpy(attrs, default_attrs, sizeof(default_attrs));

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