• Ingo Molnar's avatar
    perf stat: Add stalled cycles to the default output · 1fc570ad
    Ingo Molnar authored
    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: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
    Acked-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    Cc: Frederic Weisbecker <fweisbec@gmail.com>
    Link: http://lkml.kernel.org/n/tip-pbpl2l4mn797s69bclfpwkwn@git.kernel.orgSigned-off-by: default avatarIngo Molnar <mingo@elte.hu>
    1fc570ad
builtin-stat.c 20.8 KB