1. 25 May, 2009 9 commits
    • Peter Zijlstra's avatar
      perf_counter: Fix PERF_COUNTER_CONTEXT_SWITCHES for cpu counters · 10989fb2
      Peter Zijlstra authored
      Ingo noticed that cpu counters had 0 context switches, even though
      there was plenty scheduling on the cpu.
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      LKML-Reference: <20090525124600.419025548@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      10989fb2
    • Peter Zijlstra's avatar
      perf_counter: Propagate inheritance failures down the fork() path · 6ab423e0
      Peter Zijlstra authored
      Fail fork() when we fail inheritance for some reason (-ENOMEM most likely).
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      LKML-Reference: <20090525124600.324656474@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      6ab423e0
    • Peter Zijlstra's avatar
      perf_counter: Make pctrl() affect inherited counters too · 771d7cde
      Peter Zijlstra authored
      Paul noted that the new ptcrl() didn't work on child counters.
      Reported-by: default avatarPaul Mackerras <paulus@samba.org>
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      LKML-Reference: <20090525124600.203151469@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      771d7cde
    • Peter Zijlstra's avatar
      perf_counter: Remove unused ABI bits · e527ea31
      Peter Zijlstra authored
      extra_config_len isn't used for anything, remove it.
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      LKML-Reference: <20090525124600.116035832@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      e527ea31
    • Peter Zijlstra's avatar
      perf_counter: Fix perf-$cmd invokation · 266dfb0b
      Peter Zijlstra authored
      Fix:
      
        $ perf-top
        fatal: cannot handle -top internally
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      LKML-Reference: <20090525124559.995591577@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      266dfb0b
    • Ingo Molnar's avatar
      perf stat: flip around ':k' and ':u' flags · d3f4b385
      Ingo Molnar authored
      This output:
      
       $ perf stat -e 0:1:k -e 0:1:u ./hello
        Performance counter stats for './hello':
                140131  instructions         (events)
               1906968  instructions         (events)
      
      Is quite confusing - as :k means "user instructions", :u means
      "kernel instructions".
      
      Flip them around - as the 'exclude' property is not intuitive in
      the flag naming.
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      Cc: Mike Galbraith <efault@gmx.de>
      LKML-Reference: <new-submission>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      d3f4b385
    • Ingo Molnar's avatar
      perf_counter: Move child perfcounter init to after scheduler init · e4cbb4e3
      Ingo Molnar authored
      Initialize a task's perfcounters (inherit from parent, etc.) after
      the child task's scheduler fields have been initialized already.
      
      [ Impact: cleanup ]
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      Cc: Mike Galbraith <efault@gmx.de>
      LKML-Reference: <new-submission>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      e4cbb4e3
    • Mike Galbraith's avatar
      perf top: Reduce display overhead · d94b9430
      Mike Galbraith authored
      Iterate over the symbol table once per display interval, and
      copy/sort/tally/decay only those symbols which are active.
      
      Before:
      
       top - 10:14:53 up  4:08, 17 users,  load average: 1.17, 1.53, 1.49
       Tasks: 273 total,   5 running, 268 sleeping,   0 stopped,   0 zombie
       Cpu(s):  6.9%us, 38.2%sy,  0.0%ni, 19.9%id,  0.0%wa,  0.0%hi, 35.0%si,  0.0%st
      
         PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  P COMMAND
       28504 root      20   0  1044  260  164 S   58  0.0   0:04.19 2 netserver
       28499 root      20   0  1040  412  316 R   51  0.0   0:04.15 0 netperf
       28500 root      20   0  1040  408  316 R   50  0.0   0:04.14 1 netperf
       28503 root      20   0  1044  260  164 S   50  0.0   0:04.01 1 netserver
       28501 root      20   0  1044  260  164 S   49  0.0   0:03.99 0 netserver
       28502 root      20   0  1040  412  316 S   43  0.0   0:03.96 2 netperf
       28468 root      20   0 1892m 325m  972 S   16 10.8   0:10.50 3 perf
       28467 root      20   0 1892m 325m  972 R    2 10.8   0:00.72 3 perf
      
      After:
      
       top - 10:16:30 up  4:10, 17 users,  load average: 2.27, 1.88, 1.62
       Tasks: 273 total,   6 running, 267 sleeping,   0 stopped,   0 zombie
       Cpu(s):  2.5%us, 39.7%sy,  0.0%ni, 24.6%id,  0.0%wa,  0.0%hi, 33.3%si,  0.0%st
      
         PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  P COMMAND
       28590 root      20   0  1040  412  316 S   54  0.0   0:07.85 2 netperf
       28589 root      20   0  1044  260  164 R   54  0.0   0:07.84 0 netserver
       28588 root      20   0  1040  412  316 R   50  0.0   0:07.89 1 netperf
       28591 root      20   0  1044  256  164 S   50  0.0   0:07.82 1 netserver
       28587 root      20   0  1040  408  316 R   47  0.0   0:07.61 0 netperf
       28592 root      20   0  1044  260  164 R   47  0.0   0:07.85 2 netserver
       28378 root      20   0  8732 1300  860 R    2  0.0   0:01.81 3 top
       28577 root      20   0 1892m 165m  972 R    2  5.5   0:00.48 3 perf
       28578 root      20   0 1892m 165m  972 S    2  5.5   0:00.04 3 perf
      
      [ Impact: optimization ]
      Signed-off-by: default avatarMike Galbraith <efault@gmx.de>
      Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      LKML-Reference: <new-submission>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      d94b9430
    • Ingo Molnar's avatar
      perf_counter tools: increase limits, fix · 85a9f920
      Ingo Molnar authored
      NR_CPUS and NR_COUNTERS goes up quadratic ... 1024x4096 was far
      too ambitious upper limit - go for 256x256 which is still plenty.
      
      [ Impact: reduce perf tool memory consumption ]
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      Cc: Mike Galbraith <efault@gmx.de>
      LKML-Reference: <new-submission>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      85a9f920
  2. 24 May, 2009 4 commits
    • Ingo Molnar's avatar
      perf_counter: Increase mmap limit · a3862d3f
      Ingo Molnar authored
      In a default 'perf top' run the tool will create a counter for
      each online CPU. With enough CPUs this will eventually exhaust
      the default limit.
      
      So scale it up with the number of online CPUs.
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      Cc: Mike Galbraith <efault@gmx.de>
      LKML-Reference: <new-submission>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      a3862d3f
    • Mike Galbraith's avatar
      perf top: fix segfault · c2990a2a
      Mike Galbraith authored
      c6eb13 increased stack usage such that perf-top now croaks on startup.
      
      Take event_array and mmap_array off the stack to prevent segfault on boxen
      with smallish ulimit -s setting.
      Signed-off-by: default avatarMike Galbraith <efault@gmx.de>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      LKML-Reference: <new-submission>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      c2990a2a
    • Peter Zijlstra's avatar
      perf_counter: Remove perf_counter_context::nr_enabled · 475c5579
      Peter Zijlstra authored
      now that pctrl() no longer disables other people's counters,
      remove the PMU cache code that deals with that.
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      LKML-Reference: <20090523163013.032998331@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      475c5579
    • Peter Zijlstra's avatar
      perf_counter: Change pctrl() behaviour · 082ff5a2
      Peter Zijlstra authored
      Instead of en/dis-abling all counters acting on a particular
      task, en/dis- able all counters we created.
      
      [ v2: fix crash on first counter enable ]
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      LKML-Reference: <20090523163012.916937244@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      082ff5a2
  3. 23 May, 2009 5 commits
    • Peter Zijlstra's avatar
      perf_counter: Simplify context cleanup · aa9c67f5
      Peter Zijlstra authored
      Use perf_counter_remove_from_context() to remove counters from
      the context.
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      LKML-Reference: <20090523163012.796275849@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      aa9c67f5
    • Peter Zijlstra's avatar
      perf_counter: Fix userspace build · 1a482f38
      Peter Zijlstra authored
      recent userspace (F11) seems to already include the
      linux/unistd.h bits which means we cannot include the version
      in the kernel sources due to the header guards being the same.
      
      Ensure we include the kernel version first.
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      LKML-Reference: <20090523163012.739756497@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      1a482f38
    • Peter Zijlstra's avatar
      perf_counter: Sanitize context locking · 682076ae
      Peter Zijlstra authored
      Ensure we're consistent with the context locks.
      
       context->mutex
         context->lock
           list_{add,del}_counter();
      
      so that either lock is sufficient to stabilize the context.
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      LKML-Reference: <20090523163012.618790733@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      682076ae
    • Peter Zijlstra's avatar
      perf_counter: Sanitize counter->mutex · fccc714b
      Peter Zijlstra authored
      s/counter->mutex/counter->child_mutex/ and make sure its only
      used to protect child_list.
      
      The usage in __perf_counter_exit_task() doesn't appear to be
      problematic since ctx->mutex also covers anything related to fd
      tear-down.
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      LKML-Reference: <20090523163012.533186528@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      fccc714b
    • Peter Zijlstra's avatar
      perf_counter: Fix dynamic irq_period logging · e220d2dc
      Peter Zijlstra authored
      We call perf_adjust_freq() from perf_counter_task_tick() which
      is is called under the rq->lock causing lock recursion.
      However, it's no longer required to be called under the
      rq->lock, so remove it from under it.
      
      Also, fix up some related comments.
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      LKML-Reference: <20090523163012.476197912@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      e220d2dc
  4. 22 May, 2009 4 commits
    • Ingo Molnar's avatar
      perf_counter tools: increase limits · c6eb1384
      Ingo Molnar authored
      I tried to run with 300 active counters and the tools bailed out
      because our limit was at 64. So increase the counter limit to 1024
      and the CPU limit to 4096.
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Marcelo Tosatti <mtosatti@redhat.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      LKML-Reference: <new-submission>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      c6eb1384
    • Ingo Molnar's avatar
      perf_counter: fix !PERF_COUNTERS build failure · 910431c7
      Ingo Molnar authored
      Update the !CONFIG_PERF_COUNTERS prototype too, for
      perf_counter_task_sched_out().
      
      [ Impact: build fix ]
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
      Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Marcelo Tosatti <mtosatti@redhat.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      LKML-Reference: <18966.10666.517218.332164@cargo.ozlabs.ibm.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      910431c7
    • Paul Mackerras's avatar
      perf_counter: Optimize context switch between identical inherited contexts · 564c2b21
      Paul Mackerras authored
      When monitoring a process and its descendants with a set of inherited
      counters, we can often get the situation in a context switch where
      both the old (outgoing) and new (incoming) process have the same set
      of counters, and their values are ultimately going to be added together.
      In that situation it doesn't matter which set of counters are used to
      count the activity for the new process, so there is really no need to
      go through the process of reading the hardware counters and updating
      the old task's counters and then setting up the PMU for the new task.
      
      This optimizes the context switch in this situation.  Instead of
      scheduling out the perf_counter_context for the old task and
      scheduling in the new context, we simply transfer the old context
      to the new task and keep using it without interruption.  The new
      context gets transferred to the old task.  This means that both
      tasks still have a valid perf_counter_context, so no special case
      is introduced when the old task gets scheduled in again, either on
      this CPU or another CPU.
      
      The equivalence of contexts is detected by keeping a pointer in
      each cloned context pointing to the context it was cloned from.
      To cope with the situation where a context is changed by adding
      or removing counters after it has been cloned, we also keep a
      generation number on each context which is incremented every time
      a context is changed.  When a context is cloned we take a copy
      of the parent's generation number, and two cloned contexts are
      equivalent only if they have the same parent and the same
      generation number.  In order that the parent context pointer
      remains valid (and is not reused), we increment the parent
      context's reference count for each context cloned from it.
      
      Since we don't have individual fds for the counters in a cloned
      context, the only thing that can make two clones of a given parent
      different after they have been cloned is enabling or disabling all
      counters with prctl.  To account for this, we keep a count of the
      number of enabled counters in each context.  Two contexts must have
      the same number of enabled counters to be considered equivalent.
      
      Here are some measurements of the context switch time as measured with
      the lat_ctx benchmark from lmbench, comparing the times obtained with
      and without this patch series:
      
      		-----Unmodified-----		With this patch series
      Counters:	none	2 HW	4H+4S	none	2 HW	4H+4S
      
      2 processes:
      Average		3.44	6.45	11.24	3.12	3.39	3.60
      St dev		0.04	0.04	0.13	0.05	0.17	0.19
      
      8 processes:
      Average		6.45	8.79	14.00	5.57	6.23	7.57
      St dev		1.27	1.04	0.88	1.42	1.46	1.42
      
      32 processes:
      Average		5.56	8.43	13.78	5.28	5.55	7.15
      St dev		0.41	0.47	0.53	0.54	0.57	0.81
      
      The numbers are the mean and standard deviation of 20 runs of
      lat_ctx.  The "none" columns are lat_ctx run directly without any
      counters.  The "2 HW" columns are with lat_ctx run under perfstat,
      counting cycles and instructions.  The "4H+4S" columns are lat_ctx run
      under perfstat with 4 hardware counters and 4 software counters
      (cycles, instructions, cache references, cache misses, task
      clock, context switch, cpu migrations, and page faults).
      
      [ Impact: performance optimization of counter context-switches ]
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
      Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Marcelo Tosatti <mtosatti@redhat.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      LKML-Reference: <18966.10666.517218.332164@cargo.ozlabs.ibm.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      564c2b21
    • Paul Mackerras's avatar
      perf_counter: Dynamically allocate tasks' perf_counter_context struct · a63eaf34
      Paul Mackerras authored
      This replaces the struct perf_counter_context in the task_struct with
      a pointer to a dynamically allocated perf_counter_context struct.  The
      main reason for doing is this is to allow us to transfer a
      perf_counter_context from one task to another when we do lazy PMU
      switching in a later patch.
      
      This has a few side-benefits: the task_struct becomes a little smaller,
      we save some memory because only tasks that have perf_counters attached
      get a perf_counter_context allocated for them, and we can remove the
      inclusion of <linux/perf_counter.h> in sched.h, meaning that we don't
      end up recompiling nearly everything whenever perf_counter.h changes.
      
      The perf_counter_context structures are reference-counted and freed
      when the last reference is dropped.  A context can have references
      from its task and the counters on its task.  Counters can outlive the
      task so it is possible that a context will be freed well after its
      task has exited.
      
      Contexts are allocated on fork if the parent had a context, or
      otherwise the first time that a per-task counter is created on a task.
      In the latter case, we set the context pointer in the task struct
      locklessly using an atomic compare-and-exchange operation in case we
      raced with some other task in creating a context for the subject task.
      
      This also removes the task pointer from the perf_counter struct.  The
      task pointer was not used anywhere and would make it harder to move a
      context from one task to another.  Anything that needed to know which
      task a counter was attached to was already using counter->ctx->task.
      
      The __perf_counter_init_context function moves up in perf_counter.c
      so that it can be called from find_get_context, and now initializes
      the refcount, but is otherwise unchanged.
      
      We were potentially calling list_del_counter twice: once from
      __perf_counter_exit_task when the task exits and once from
      __perf_counter_remove_from_context when the counter's fd gets closed.
      This adds a check in list_del_counter so it doesn't do anything if
      the counter has already been removed from the lists.
      
      Since perf_counter_task_sched_in doesn't do anything if the task doesn't
      have a context, and leaves cpuctx->task_ctx = NULL, this adds code to
      __perf_install_in_context to set cpuctx->task_ctx if necessary, i.e. in
      the case where the current task adds the first counter to itself and
      thus creates a context for itself.
      
      This also adds similar code to __perf_counter_enable to handle a
      similar situation which can arise when the counters have been disabled
      using prctl; that also leaves cpuctx->task_ctx = NULL.
      
      [ Impact: refactor counter context management to prepare for new feature ]
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
      Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Marcelo Tosatti <mtosatti@redhat.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      LKML-Reference: <18966.10075.781053.231153@cargo.ozlabs.ibm.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      a63eaf34
  5. 20 May, 2009 5 commits
    • Ingo Molnar's avatar
      perf_counter: Fix context removal deadlock · 34adc806
      Ingo Molnar authored
      Disable the PMU globally before removing a counter from a
      context. This fixes the following lockup:
      
      [22081.741922] ------------[ cut here ]------------
      [22081.746668] WARNING: at arch/x86/kernel/cpu/perf_counter.c:803 intel_pmu_handle_irq+0x9b/0x24e()
      [22081.755624] Hardware name: X8DTN
      [22081.758903] perfcounters: irq loop stuck!
      [22081.762985] Modules linked in:
      [22081.766136] Pid: 11082, comm: perf Not tainted 2.6.30-rc6-tip #226
      [22081.772432] Call Trace:
      [22081.774940]  <NMI>  [<ffffffff81019aed>] ? intel_pmu_handle_irq+0x9b/0x24e
      [22081.781993]  [<ffffffff81019aed>] ? intel_pmu_handle_irq+0x9b/0x24e
      [22081.788368]  [<ffffffff8104505c>] ? warn_slowpath_common+0x77/0xa3
      [22081.794649]  [<ffffffff810450d3>] ? warn_slowpath_fmt+0x40/0x45
      [22081.800696]  [<ffffffff81019aed>] ? intel_pmu_handle_irq+0x9b/0x24e
      [22081.807080]  [<ffffffff814d1a72>] ? perf_counter_nmi_handler+0x3f/0x4a
      [22081.813751]  [<ffffffff814d2d09>] ? notifier_call_chain+0x58/0x86
      [22081.819951]  [<ffffffff8105b250>] ? notify_die+0x2d/0x32
      [22081.825392]  [<ffffffff814d1414>] ? do_nmi+0x8e/0x242
      [22081.830538]  [<ffffffff814d0f0a>] ? nmi+0x1a/0x20
      [22081.835342]  [<ffffffff8117e102>] ? selinux_file_free_security+0x0/0x1a
      [22081.842105]  [<ffffffff81018793>] ? x86_pmu_disable_counter+0x15/0x41
      [22081.848673]  <<EOE>>  [<ffffffff81018f3d>] ? x86_pmu_disable+0x86/0x103
      [22081.855512]  [<ffffffff8108fedd>] ? __perf_counter_remove_from_context+0x0/0xfe
      [22081.862926]  [<ffffffff8108fcbc>] ? counter_sched_out+0x30/0xce
      [22081.868909]  [<ffffffff8108ff36>] ? __perf_counter_remove_from_context+0x59/0xfe
      [22081.876382]  [<ffffffff8106808a>] ? smp_call_function_single+0x6c/0xe6
      [22081.882955]  [<ffffffff81091b96>] ? perf_release+0x86/0x14c
      [22081.888600]  [<ffffffff810c4c84>] ? __fput+0xe7/0x195
      [22081.893718]  [<ffffffff810c213e>] ? filp_close+0x5b/0x62
      [22081.899107]  [<ffffffff81046a70>] ? put_files_struct+0x64/0xc2
      [22081.905031]  [<ffffffff8104841a>] ? do_exit+0x1e2/0x6ef
      [22081.910360]  [<ffffffff814d0a60>] ? _spin_lock_irqsave+0x9/0xe
      [22081.916292]  [<ffffffff8104898e>] ? do_group_exit+0x67/0x93
      [22081.921953]  [<ffffffff810489cc>] ? sys_exit_group+0x12/0x16
      [22081.927759]  [<ffffffff8100baab>] ? system_call_fastpath+0x16/0x1b
      [22081.934076] ---[ end trace 3a3936ce3e1b4505 ]---
      
      And could potentially also fix the lockup reported by Marcelo Tosatti.
      
      Also, print more debug info in case of a detected lockup.
      
      [ Impact: fix lockup ]
      Reported-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
      Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      LKML-Reference: <new-submission>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      34adc806
    • Peter Zijlstra's avatar
      perf_counter: Optimize sched in/out of counters · afedadf2
      Peter Zijlstra authored
      Avoid a function call for !group counters by directly calling the counter
      function.
      
      [ Impact: micro-optimize the code ]
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Marcelo Tosatti <mtosatti@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      LKML-Reference: <20090520102553.511933670@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      afedadf2
    • Peter Zijlstra's avatar
      perf_counter: Optimize disable of time based sw counters · b986d7ec
      Peter Zijlstra authored
      Currently we call hrtimer_cancel() unconditionally on disable of time based
      software counters. Avoid when possible.
      
      [ Impact: micro-optimize the code ]
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Marcelo Tosatti <mtosatti@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      LKML-Reference: <20090520102553.388185031@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      b986d7ec
    • Peter Zijlstra's avatar
      perf_counter: Log irq_period changes · 26b119bc
      Peter Zijlstra authored
      For the dynamic irq_period code, log whenever we change the period so that
      analyzing code can normalize the event flow.
      
      [ Impact: add new feature to allow more precise profiling ]
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Marcelo Tosatti <mtosatti@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      LKML-Reference: <20090520102553.298769743@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      26b119bc
    • Peter Zijlstra's avatar
      perf_counter: Solve the rotate_ctx vs inherit race differently · d7b629a3
      Peter Zijlstra authored
      Instead of disabling RR scheduling of the counters, use a different list
      that does not get rotated to iterate the counters on inheritance.
      
      [ Impact: cleanup, optimization ]
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Marcelo Tosatti <mtosatti@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      LKML-Reference: <20090520102553.237504544@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      d7b629a3
  6. 19 May, 2009 2 commits
  7. 18 May, 2009 3 commits
    • Ingo Molnar's avatar
      perf_counter, x86: speed up the scheduling fast-path · b68f1d2e
      Ingo Molnar authored
      We have to set up the LVT entry only at counter init time, not at
      every switch-in time.
      
      There's friction between NMI and non-NMI use here - we'll probably
      remove the per counter configurability of it - but until then, dont
      slow down things ...
      
      [ Impact: micro-optimization ]
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Marcelo Tosatti <mtosatti@redhat.com>
      LKML-Reference: <new-submission>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      b68f1d2e
    • Paul Mackerras's avatar
      perf_counter: powerpc: initialize cpuhw pointer before use · c0daaf3f
      Paul Mackerras authored
      Commit 9e35ad38 ("perf_counter: Rework the perf counter
      disable/enable") added code to the powerpc hw_perf_enable (renamed
      from hw_perf_restore) to test cpuhw->disabled and return immediately
      if it is not set (i.e. if the PMU is already enabled).
      
      Unfortunately the test got added before cpuhw was initialized,
      resulting in an oops the first time hw_perf_enable got called.
      This fixes it by moving the initialization of cpuhw to before
      cpuhw->disabled is tested.
      
      [ Impact: fix oops-causing bug on powerpc ]
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      LKML-Reference: <18960.56772.869734.304631@drongo.ozlabs.ibm.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      c0daaf3f
    • Ingo Molnar's avatar
      Merge commit 'v2.6.30-rc6' into perfcounters/core · dc3f81b1
      Ingo Molnar authored
      Merge reason: this branch was on an -rc4 base, merge it up to -rc6
                    to get the latest upstream fixes.
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      dc3f81b1
  8. 17 May, 2009 4 commits
    • Ingo Molnar's avatar
      perf_counter, x86: fix zero irq_period counters · d2517a49
      Ingo Molnar authored
      The quirk to irq_period unearthed an unrobustness we had in the
      hw_counter initialization sequence: we left irq_period at 0, which
      was then quirked up to 2 ... which then generated a _lot_ of
      interrupts during 'perf stat' runs, slowed them down and skewed
      the counter results in general.
      
      Initialize irq_period to the maximum instead.
      
      [ Impact: fix perf stat results ]
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Marcelo Tosatti <mtosatti@redhat.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      d2517a49
    • Ingo Molnar's avatar
      perf_counter: fix threaded task exit · 0203026b
      Ingo Molnar authored
      Flushing counters in __exit_signal() with irqs disabled is not
      a good idea as perf_counter_exit_task() acquires mutexes. So
      flush it before acquiring the tasklist lock.
      
      (Note, we still need a fix for when the PID has been unhashed.)
      
      [ Impact: fix crash with inherited counters ]
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Marcelo Tosatti <mtosatti@redhat.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      0203026b
    • Peter Zijlstra's avatar
      perf_counter: Fix counter inheritance · 856d56b9
      Peter Zijlstra authored
      Srivatsa Vaddagiri reported that a Java workload triggers this
      warning in kernel/exit.c:
      
         WARN_ON_ONCE(!list_empty(&tsk->perf_counter_ctx.counter_list));
      
      Add the inherited counter propagation on self-detach, this could
      cause counter leaks and incomplete stats in threaded code like
      the below:
      
        #include <pthread.h>
        #include <unistd.h>
      
        void *thread(void *arg)
        {
                sleep(5);
                return NULL;
        }
      
        void main(void)
        {
                pthread_t thr;
                pthread_create(&thr, NULL, thread, NULL);
        }
      Reported-by: default avatarSrivatsa Vaddagiri <vatsa@in.ibm.com>
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Marcelo Tosatti <mtosatti@redhat.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      856d56b9
    • Peter Zijlstra's avatar
      perf_counter: Fix inheritance cleanup code · 8bc20959
      Peter Zijlstra authored
      Clean up code that open-coded the list_{add,del}_counter() code in
      __perf_counter_exit_task() which consequently diverged. This could
      lead to software counter crashes.
      
      Also, fold the ctx->nr_counter inc/dec into those functions and clean
      up some of the related code.
      
      [ Impact: fix potential sw counter crash, cleanup ]
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Marcelo Tosatti <mtosatti@redhat.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      8bc20959
  9. 16 May, 2009 1 commit
  10. 15 May, 2009 3 commits