• Davidlohr Bueso's avatar
    perf bench: Add futex-hash microbenchmark · a0439711
    Davidlohr Bueso authored
    Introduce futexes to perf-bench and add a program that stresses and
    measures the kernel's implementation of the hash table.
    
    This is a multi-threaded program that simply measures the amount of
    failed futex wait calls - we only want to deal with the hashing
    overhead, so a negative return of futex_wait_setup() is enough to do the
    trick.
    
    An example run:
    
      $ perf bench futex hash -t 32
      Run summary [PID 10989]: 32 threads, each operating on 1024 [private] futexes for 10 secs.
    
      [thread  0] futexes: 0x19d9b10 ... 0x19dab0c [ 418713 ops/sec ]
      [thread  1] futexes: 0x19daca0 ... 0x19dbc9c [ 469913 ops/sec ]
      [thread  2] futexes: 0x19dbe30 ... 0x19dce2c [ 479744 ops/sec ]
      ...
      [thread 31] futexes: 0x19fbb80 ... 0x19fcb7c [ 464179 ops/sec ]
    
      Averaged 454310 operations/sec (+- 0.84%), total secs = 10
    Signed-off-by: default avatarDavidlohr Bueso <davidlohr@hp.com>
    Acked-by: default avatarDarren Hart <dvhart@linux.intel.com>
    Cc: Aswin Chandramouleeswaran <aswin@hp.com>
    Cc: Darren Hart <dvhart@linux.intel.com>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Jason Low <jason.low2@hp.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Scott J Norton <scott.norton@hp.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Waiman Long <Waiman.Long@hp.com>
    Link: http://lkml.kernel.org/r/1387081917-9102-2-git-send-email-davidlohr@hp.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    a0439711
futex-hash.c 5.64 KB