From d3d1e86da07b4565815e3dbcd082f53017d215f8 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 29 Apr 2011 13:49:08 +0200 Subject: [PATCH] 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 Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker Link: http://lkml.kernel.org/n/tip-7y40wib8n003io7hjpn1dsrm@git.kernel.org Signed-off-by: Ingo Molnar --- 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 6a4a8a399d95..e45449938b80 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 04d2f0a96674..8a407f3e286f 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",