[tip:perf/stat] perf stat: Analyze front-end and back-end stall counts
From: tip-bot for Ingo Molnar
Date: Fri Apr 29 2011 - 08:47:28 EST
Commit-ID: d3d1e86da07b4565815e3dbcd082f53017d215f8
Gitweb: http://git.kernel.org/tip/d3d1e86da07b4565815e3dbcd082f53017d215f8
Author: Ingo Molnar <mingo@xxxxxxx>
AuthorDate: Fri, 29 Apr 2011 13:49:08 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Fri, 29 Apr 2011 14:35:55 +0200
perf stat: Analyze front-end and back-end stall counts
Sample output:
Performance counter stats for './loop_1b':
873.691065 task-clock # 1.000 CPUs utilized
1 context-switches # 0.000 M/sec
1 CPU-migrations # 0.000 M/sec
96 page-faults # 0.000 M/sec
2,012,637,222 cycles # 2.304 GHz (66.58%)
1,001,397,911 stalled-cycles-frontend # 49.76% frontend cycles idle (66.58%)
7,523,398 stalled-cycles-backend # 0.37% backend cycles idle (66.76%)
2,004,551,046 instructions # 1.00 insns per cycle
# 0.50 stalled cycles per insn (66.80%)
1,001,304,992 branches # 1146.063 M/sec (66.76%)
39,453 branch-misses # 0.00% of all branches (66.64%)
0.874046121 seconds time elapsed
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-7y40wib8n003io7hjpn1dsrm@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
tools/perf/builtin-stat.c | 41 ++++++++++++++++++++++++++++++++++-----
tools/perf/util/parse-events.c | 7 +++--
2 files changed, 39 insertions(+), 9 deletions(-)
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 6a4a8a3..e454499 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -201,7 +201,8 @@ static double stddev_stats(struct stats *stats)
struct stats runtime_nsecs_stats[MAX_NR_CPUS];
struct stats runtime_cycles_stats[MAX_NR_CPUS];
-struct stats runtime_stalled_cycles_stats[MAX_NR_CPUS];
+struct stats runtime_stalled_cycles_front_stats[MAX_NR_CPUS];
+struct stats runtime_stalled_cycles_back_stats[MAX_NR_CPUS];
struct stats runtime_branches_stats[MAX_NR_CPUS];
struct stats runtime_cacherefs_stats[MAX_NR_CPUS];
struct stats runtime_l1_dcache_stats[MAX_NR_CPUS];
@@ -251,8 +252,10 @@ static void update_shadow_stats(struct perf_evsel *counter, u64 *count)
update_stats(&runtime_nsecs_stats[0], count[0]);
else if (perf_evsel__match(counter, HARDWARE, HW_CPU_CYCLES))
update_stats(&runtime_cycles_stats[0], count[0]);
+ else if (perf_evsel__match(counter, HARDWARE, HW_STALLED_CYCLES_FRONTEND))
+ update_stats(&runtime_stalled_cycles_front_stats[0], count[0]);
else if (perf_evsel__match(counter, HARDWARE, HW_STALLED_CYCLES_BACKEND))
- update_stats(&runtime_stalled_cycles_stats[0], count[0]);
+ update_stats(&runtime_stalled_cycles_back_stats[0], count[0]);
else if (perf_evsel__match(counter, HARDWARE, HW_BRANCH_INSTRUCTIONS))
update_stats(&runtime_branches_stats[0], count[0]);
else if (perf_evsel__match(counter, HARDWARE, HW_CACHE_REFERENCES))
@@ -478,7 +481,30 @@ static void nsec_printout(int cpu, struct perf_evsel *evsel, double avg)
fprintf(stderr, " # %8.3f CPUs utilized ", avg / avg_stats(&walltime_nsecs_stats));
}
-static void print_stalled_cycles(int cpu, struct perf_evsel *evsel __used, double avg)
+static void print_stalled_cycles_frontend(int cpu, struct perf_evsel *evsel __used, double avg)
+{
+ double total, ratio = 0.0;
+ const char *color;
+
+ total = avg_stats(&runtime_cycles_stats[cpu]);
+
+ if (total)
+ ratio = avg / total * 100.0;
+
+ color = PERF_COLOR_NORMAL;
+ if (ratio > 75.0)
+ color = PERF_COLOR_RED;
+ else if (ratio > 50.0)
+ color = PERF_COLOR_MAGENTA;
+ else if (ratio > 20.0)
+ color = PERF_COLOR_YELLOW;
+
+ fprintf(stderr, " # ");
+ color_fprintf(stderr, color, "%5.2f%%", ratio);
+ fprintf(stderr, " frontend cycles idle ");
+}
+
+static void print_stalled_cycles_backend(int cpu, struct perf_evsel *evsel __used, double avg)
{
double total, ratio = 0.0;
const char *color;
@@ -498,7 +524,7 @@ static void print_stalled_cycles(int cpu, struct perf_evsel *evsel __used, doubl
fprintf(stderr, " # ");
color_fprintf(stderr, color, "%5.2f%%", ratio);
- fprintf(stderr, " of all cycles are idle ");
+ fprintf(stderr, " backend cycles idle ");
}
static void print_branch_misses(int cpu, struct perf_evsel *evsel __used, double avg)
@@ -583,7 +609,8 @@ static void abs_printout(int cpu, struct perf_evsel *evsel, double avg)
fprintf(stderr, " # %4.2f insns per cycle ", ratio);
- total = avg_stats(&runtime_stalled_cycles_stats[cpu]);
+ total = avg_stats(&runtime_stalled_cycles_front_stats[cpu]);
+ total = max(total, avg_stats(&runtime_stalled_cycles_back_stats[cpu]));
if (total && avg) {
ratio = total / avg;
@@ -609,8 +636,10 @@ static void abs_printout(int cpu, struct perf_evsel *evsel, double avg)
fprintf(stderr, " # %8.3f %% of all cache refs ", ratio);
+ } else if (perf_evsel__match(evsel, HARDWARE, HW_STALLED_CYCLES_FRONTEND)) {
+ print_stalled_cycles_frontend(cpu, evsel, avg);
} else if (perf_evsel__match(evsel, HARDWARE, HW_STALLED_CYCLES_BACKEND)) {
- print_stalled_cycles(cpu, evsel, avg);
+ print_stalled_cycles_backend(cpu, evsel, avg);
} else if (perf_evsel__match(evsel, HARDWARE, HW_CPU_CYCLES)) {
total = avg_stats(&runtime_nsecs_stats[cpu]);
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 04d2f0a..8a407f3 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -60,7 +60,7 @@ static struct event_symbol event_symbols[] = {
#define PERF_EVENT_TYPE(config) __PERF_EVENT_FIELD(config, TYPE)
#define PERF_EVENT_ID(config) __PERF_EVENT_FIELD(config, EVENT)
-static const char *hw_event_names[] = {
+static const char *hw_event_names[PERF_COUNT_HW_MAX] = {
"cycles",
"instructions",
"cache-references",
@@ -68,10 +68,11 @@ static const char *hw_event_names[] = {
"branches",
"branch-misses",
"bus-cycles",
- "stalled-cycles",
+ "stalled-cycles-frontend",
+ "stalled-cycles-backend",
};
-static const char *sw_event_names[] = {
+static const char *sw_event_names[PERF_COUNT_SW_MAX] = {
"cpu-clock",
"task-clock",
"page-faults",
--
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