perf stat: Analyze front-end and back-end stall counts
Commit-ID: d3d1e86da07b4565815e3dbcd082f53017d215f8 Gitweb: http://git.kernel.org/tip/d3d1e86da07b4565815e3dbcd082f53017d215f8 Author: Ingo Molnar <[email protected]> AuthorDate: Fri, 29 Apr 2011 13:49:08 +0200 Committer: Ingo Molnar <[email protected]> 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 <[email protected]>
Cc Arnaldo Carvalho de Melo <[email protected]>
Cc Frederic Weisbecker <[email protected]>
Signed-off-by Ingo Molnar <[email protected]>
--- tools/perf/builtin-stat.c | 41 ++++++++++++++++++++++++++++++++++----- tools/perf/util/parse-events.c | 7 +++-- 2 files changed, 39 insertions(+), 9 deletions(-)
tools/perf/builtin-stat.c +35 -6
@@ -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, doublfprintf (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]);
tools/perf/util/parse-events.c +4 -3
@@ -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",