1. 03 Sep, 2010 1 commit
    • Don Zickus's avatar
      perf, x86: Fix accidentally ack'ing a second event on intel perf counter · 2e556b5b
      Don Zickus authored
      During testing of a patch to stop having the perf subsytem
      swallow nmis, it was uncovered that Nehalem boxes were randomly
      getting unknown nmis when using the perf tool.
      
      Moving the ack'ing of the PMI closer to when we get the status
      allows the hardware to properly re-set the PMU bit signaling
      another PMI was triggered during the processing of the first
      PMI.  This allows the new logic for dealing with the
      shortcomings of multiple PMIs to handle the extra NMI by
      'eat'ing it later.
      
      Now one can wonder why are we getting a second PMI when we
      disable all the PMUs in the begining of the NMI handler to
      prevent such a case, for that I do not know.  But I know the fix
      below helps deal with this quirk.
      
      Tested on multiple Nehalems where the problem was occuring.
      With the patch, the code now loops a second time to handle the
      second PMI (whereas before it was not).
      Signed-off-by: default avatarDon Zickus <dzickus@redhat.com>
      Cc: peterz@infradead.org
      Cc: robert.richter@amd.com
      Cc: gorcunov@gmail.com
      Cc: fweisbec@gmail.com
      Cc: ying.huang@intel.com
      Cc: ming.m.lin@intel.com
      Cc: eranian@google.com
      LKML-Reference: <1283454469-1909-2-git-send-email-dzickus@redhat.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      2e556b5b
  2. 01 Sep, 2010 3 commits
  3. 31 Aug, 2010 2 commits
  4. 30 Aug, 2010 1 commit
    • Stephane Eranian's avatar
      perf_events: Fix time tracking for events with pid != -1 and cpu != -1 · fa66f07a
      Stephane Eranian authored
      Per-thread events with a cpu filter, i.e., cpu != -1, were not
      reporting correct timings when the thread never ran on the
      monitored cpu. The time enabled was reported as a negative
      value.
      
      This patch fixes the problem by updating tstamp_stopped,
      tstamp_running in event_sched_out() for events with filters and
      which are marked as INACTIVE.
      
      The function group_sched_out() is modified to systematically
      call into event_sched_out() to avoid duplicating the timing
      adjustment code twice.
      
      With the patch, I now get:
      
      $ task_cpu -i -e unhalted_core_cycles,unhalted_core_cycles
      noploop 2 noploop for 2 seconds
      CPU0 0		   unhalted_core_cycles (ena=1,991,136,594, run=0)
      CPU0 0		   unhalted_core_cycles (ena=1,991,136,594, run=0)
      
      CPU1 0		   unhalted_core_cycles (ena=1,991,136,594, run=0)
      CPU1 0		   unhalted_core_cycles (ena=1,991,136,594, run=0)
      
      CPU2 0		   unhalted_core_cycles (ena=1,991,136,594, run=0)
      CPU2 0		   unhalted_core_cycles (ena=1,991,136,594, run=0)
      
      CPU3 4,747,990,931 unhalted_core_cycles (ena=1,991,136,594, run=1,991,136,594)
      CPU3 4,747,990,931 unhalted_core_cycles (ena=1,991,136,594, run=1,991,136,594)
      Signed-off-by: default avatarStephane Eranian <eranian@gmail.com>
      Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: paulus@samba.org
      Cc: davem@davemloft.net
      Cc: fweisbec@gmail.com
      Cc: perfmon2-devel@lists.sf.net
      Cc: eranian@google.com
      LKML-Reference: <4c76802d.aae9d80a.115d.70fe@mx.google.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      fa66f07a
  5. 26 Aug, 2010 1 commit
    • Frederic Weisbecker's avatar
      perf: Initialize callchains roots's childen hits · 5225c458
      Frederic Weisbecker authored
      Each histogram entry has a callchain root that stores the
      callchain samples. However we forgot to initialize the
      tracking of children hits of these roots, which then got
      random values on their creation.
      
      The root children hits is multiplied by the minimum percentage
      of hits provided by the user, and the result becomes the minimum
      hits expected from children branches. If the random value due
      to the uninitialization is big enough, then this minimum number
      of hits can be huge and eventually filter every children branches.
      
      The end result was invisible callchains. All we need to
      fix this is to initialize the children hits of the root.
      Reported-by: default avatarChristoph Hellwig <hch@infradead.org>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: 2.6.32.x-2.6.35.y <stable@kernel.org>
      5225c458
  6. 25 Aug, 2010 3 commits
    • Lin Ming's avatar
      perf, x86, Pentium4: Clear the P4_CCCR_FORCE_OVF flag · 8d330919
      Lin Ming authored
      If on Pentium4 CPUs the FORCE_OVF flag is set then an NMI happens
      on every event, which can generate a flood of NMIs. Clear it.
      Reported-by: default avatarVince Weaver <vweaver1@eecs.utk.edu>
      Signed-off-by: default avatarLin Ming <ming.m.lin@intel.com>
      Signed-off-by: default avatarCyrill Gorcunov <gorcunov@openvz.org>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: <stable@kernel.org>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      8d330919
    • Anton Blanchard's avatar
      tracing/trace_stack: Fix stack trace on ppc64 · 151772db
      Anton Blanchard authored
      save_stack_trace() stores the instruction pointer, not the
      function descriptor. On ppc64 the trace stack code currently
      dereferences the instruction pointer and shows 8 bytes of
      instructions in our backtraces:
      
       # cat /sys/kernel/debug/tracing/stack_trace
              Depth    Size   Location    (26 entries)
              -----    ----   --------
        0)     5424     112   0x6000000048000004
        1)     5312     160   0x60000000ebad01b0
        2)     5152     160   0x2c23000041c20030
        3)     4992     240   0x600000007c781b79
        4)     4752     160   0xe84100284800000c
        5)     4592     192   0x600000002fa30000
        6)     4400     256   0x7f1800347b7407e0
        7)     4144     208   0xe89f0108f87f0070
        8)     3936     272   0xe84100282fa30000
      
      Since we aren't dealing with function descriptors, use %pS
      instead of %pF to fix it:
      
       # cat /sys/kernel/debug/tracing/stack_trace
              Depth    Size   Location    (26 entries)
              -----    ----   --------
        0)     5424     112   ftrace_call+0x4/0x8
        1)     5312     160   .current_io_context+0x28/0x74
        2)     5152     160   .get_io_context+0x48/0xa0
        3)     4992     240   .cfq_set_request+0x94/0x4c4
        4)     4752     160   .elv_set_request+0x60/0x84
        5)     4592     192   .get_request+0x2d4/0x468
        6)     4400     256   .get_request_wait+0x7c/0x258
        7)     4144     208   .__make_request+0x49c/0x610
        8)     3936     272   .generic_make_request+0x390/0x434
      Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
      Cc: rostedt@goodmis.org
      Cc: fweisbec@gmail.com
      LKML-Reference: <20100825013238.GE28360@kryten>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      151772db
    • Robert Richter's avatar
      oprofile: fix crash when accessing freed task structs · 750d857c
      Robert Richter authored
      This patch fixes a crash during shutdown reported below. The crash is
      caused by accessing already freed task structs. The fix changes the
      order for registering and unregistering notifier callbacks.
      
      All notifiers must be initialized before buffers start working. To
      stop buffer synchronization we cancel all workqueues, unregister the
      notifier callback and then flush all buffers. After all of this we
      finally can free all tasks listed.
      
      This should avoid accessing freed tasks.
      
      On 22.07.10 01:14:40, Benjamin Herrenschmidt wrote:
      
      > So the initial observation is a spinlock bad magic followed by a crash
      > in the spinlock debug code:
      >
      > [ 1541.586531] BUG: spinlock bad magic on CPU#5, events/5/136
      > [ 1541.597564] Unable to handle kernel paging request for data at address 0x6b6b6b6b6b6b6d03
      >
      > Backtrace looks like:
      >
      >       spin_bug+0x74/0xd4
      >       ._raw_spin_lock+0x48/0x184
      >       ._spin_lock+0x10/0x24
      >       .get_task_mm+0x28/0x8c
      >       .sync_buffer+0x1b4/0x598
      >       .wq_sync_buffer+0xa0/0xdc
      >       .worker_thread+0x1d8/0x2a8
      >       .kthread+0xa8/0xb4
      >       .kernel_thread+0x54/0x70
      >
      > So we are accessing a freed task struct in the work queue when
      > processing the samples.
      Reported-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: stable@kernel.org
      Signed-off-by: default avatarRobert Richter <robert.richter@amd.com>
      750d857c
  7. 24 Aug, 2010 29 commits