1. 29 1月, 2010 7 次提交
  2. 28 1月, 2010 1 次提交
    • A
      perf: Fix inconsistency between IP and callchain sampling · 339ce1a4
      Anton Blanchard 提交于
      When running perf across all cpus with backtracing (-a -g), sometimes we
      get samples without associated backtraces:
      
          23.44%         init  [kernel]                     [k] restore
          11.46%         init                       eeba0c  [k] 0x00000000eeba0c
           6.77%      swapper  [kernel]                     [k] .perf_ctx_adjust_freq
           5.73%         init  [kernel]                     [k] .__trace_hcall_entry
           4.69%         perf  libc-2.9.so                  [.] 0x0000000006bb8c
                             |
                             |--11.11%-- 0xfffa941bbbc
      
      It turns out the backtrace code has a check for the idle task and the IP
      sampling does not. This creates problems when profiling an interrupt
      heavy workload (in my case 10Gbit ethernet) since we get no backtraces
      for interrupts received while idle (ie most of the workload).
      
      Right now x86 and sh check that current is not NULL, which should never
      happen so remove that too.
      
      Idle task's exclusion must be performed from the core code, on top
      of perf_event_attr:exclude_idle.
      Signed-off-by: NAnton Blanchard <anton@samba.org>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mundt <lethal@linux-sh.org>
      LKML-Reference: <20100118054707.GT12666@kryten>
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      339ce1a4
  3. 13 1月, 2010 28 次提交
  4. 12 1月, 2010 4 次提交