perf stat: Add stalled cycles to the default output
Ingo Molnar [Wed, 27 Apr 2011 03:20:22 +0000 (05:20 +0200)]
The new default output looks like this:

 Performance counter stats for './loop_1b_instructions':

        236.010686 task-clock               #    0.996 CPUs utilized
                 0 context-switches         #    0.000 M/sec
                 0 CPU-migrations           #    0.000 M/sec
                99 page-faults              #    0.000 M/sec
       756,487,646 cycles                   #    3.205 GHz
       354,938,996 stalled-cycles           #   46.92% of all cycles are idle
     1,001,403,797 instructions             #    1.32  insns per cycle
                                            #    0.35  stalled cycles per insn
       100,279,773 branches                 #  424.895 M/sec
            12,646 branch-misses            #    0.013 % of all branches

        0.236902540  seconds time elapsed

We dropped cache-refs and cache-misses and added stalled-cycles - this is a
more generic "how well utilized is the CPU" metric.

If the stalled-cycles ratio is too high then more specific measurements can be
taken to figure out the source of the inefficiency.

Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/n/tip-pbpl2l4mn797s69bclfpwkwn@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/builtin-stat.c
tools/perf/util/parse-events.c

index e881c20..924d18c 100644 (file)
@@ -65,11 +65,10 @@ static struct perf_event_attr default_attrs[] = {
   { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_PAGE_FAULTS            },
 
   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CPU_CYCLES             },
+  { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_STALLED_CYCLES         },
   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_INSTRUCTIONS           },
   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS    },
   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_BRANCH_MISSES          },
-  { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CACHE_REFERENCES       },
-  { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CACHE_MISSES           },
 
 };
 
@@ -468,7 +467,7 @@ static void abs_printout(int cpu, struct perf_evsel *evsel, double avg)
                if (total)
                        ratio = avg * 100 / total;
 
-               fprintf(stderr, " # %8.3f %% of all branches", ratio);
+               fprintf(stderr, " #   %5.2f  %% of all branches      ", ratio);
 
        } else if (perf_evsel__match(evsel, HARDWARE, HW_CACHE_MISSES) &&
                        runtime_cacherefs_stats[cpu].n != 0) {
index b5bfef1..bbbb735 100644 (file)
@@ -32,13 +32,13 @@ char debugfs_path[MAXPATHLEN];
 
 static struct event_symbol event_symbols[] = {
   { CHW(CPU_CYCLES),           "cpu-cycles",           "cycles"        },
+  { CHW(STALLED_CYCLES),       "stalled-cycles",       "idle-cycles"   },
   { CHW(INSTRUCTIONS),         "instructions",         ""              },
   { CHW(CACHE_REFERENCES),     "cache-references",     ""              },
   { CHW(CACHE_MISSES),         "cache-misses",         ""              },
   { CHW(BRANCH_INSTRUCTIONS),  "branch-instructions",  "branches"      },
   { CHW(BRANCH_MISSES),                "branch-misses",        ""              },
   { CHW(BUS_CYCLES),           "bus-cycles",           ""              },
-  { CHW(STALLED_CYCLES),       "stalled-cycles",       ""              },
 
   { CSW(CPU_CLOCK),            "cpu-clock",            ""              },
   { CSW(TASK_CLOCK),           "task-clock",           ""              },
@@ -54,9 +54,9 @@ static struct event_symbol event_symbols[] = {
 #define __PERF_EVENT_FIELD(config, name) \
        ((config & PERF_EVENT_##name##_MASK) >> PERF_EVENT_##name##_SHIFT)
 
-#define PERF_EVENT_RAW(config) __PERF_EVENT_FIELD(config, RAW)
+#define PERF_EVENT_RAW(config)         __PERF_EVENT_FIELD(config, RAW)
 #define PERF_EVENT_CONFIG(config)      __PERF_EVENT_FIELD(config, CONFIG)
-#define PERF_EVENT_TYPE(config)        __PERF_EVENT_FIELD(config, TYPE)
+#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[] = {
@@ -67,6 +67,7 @@ static const char *hw_event_names[] = {
        "branches",
        "branch-misses",
        "bus-cycles",
+       "stalled-cycles",
 };
 
 static const char *sw_event_names[] = {
@@ -308,7 +309,7 @@ const char *__event_name(int type, u64 config)
 
        switch (type) {
        case PERF_TYPE_HARDWARE:
-               if (config < PERF_COUNT_HW_MAX)
+               if (config < PERF_COUNT_HW_MAX && hw_event_names[config])
                        return hw_event_names[config];
                return "unknown-hardware";
 
@@ -334,7 +335,7 @@ const char *__event_name(int type, u64 config)
        }
 
        case PERF_TYPE_SOFTWARE:
-               if (config < PERF_COUNT_SW_MAX)
+               if (config < PERF_COUNT_SW_MAX && sw_event_names[config])
                        return sw_event_names[config];
                return "unknown-software";