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2011-08-31perf_event: Fix broken calc_timer_values()Eric B Munson
We detected a serious issue with PERF_SAMPLE_READ and timing information when events were being multiplexing. Samples would have time_running > time_enabled. That was easy to reproduce with a libpfm4 example (ran 3 times to cause multiplexing on Core 2): $ syst_smpl -e uops_retired:freq=1 & $ syst_smpl -e uops_retired:freq=1 & $ syst_smpl -e uops_retired:freq=1 & IIP:0x0000000040062d ... PERIOD:2355332948 ENA=40144625315 RUN=60014875184 syst_smpl: WARNING: time_running > time_enabled 63277537998 uops_retired:freq=1 , scaled The bug was not present in kernel up to (and including) 3.0. It turns out the bug was introduced by the following commit: commit c4794295917ebeda8013b6cb9c8d71ab4f74a1fa events: Move lockless timer calculation into helper function The parameters of the function got reversed yet the call sites were not updated to reflect the change. That lead to time_running and time_enabled being swapped. That had no effect when there was no multiplexing because in that case time_running = time_enabled but it would show up in any other scenario. Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110829124112.GA4828@quad Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-08-29perf events: Fix slow and broken cgroup context switch codeStephane Eranian
The current cgroup context switch code was incorrect leading to bogus counts. Furthermore, as soon as there was an active cgroup event on a CPU, the context switch cost on that CPU would increase by a significant amount as demonstrated by a simple ping/pong example: $ ./pong Both processes pinned to CPU1, running for 10s 10684.51 ctxsw/s Now start a cgroup perf stat: $ perf stat -e cycles,cycles -A -a -G test -C 1 -- sleep 100 $ ./pong Both processes pinned to CPU1, running for 10s 6674.61 ctxsw/s That's a 37% penalty. Note that pong is not even in the monitored cgroup. The results shown by perf stat are bogus: $ perf stat -e cycles,cycles -A -a -G test -C 1 -- sleep 100 Performance counter stats for 'sleep 100': CPU1 <not counted> cycles test CPU1 16,984,189,138 cycles # 0.000 GHz The second 'cycles' event should report a count @ CPU clock (here 2.4GHz) as it is counting across all cgroups. The patch below fixes the bogus accounting and bypasses any cgroup switches in case the outgoing and incoming tasks are in the same cgroup. With this patch the same test now yields: $ ./pong Both processes pinned to CPU1, running for 10s 10775.30 ctxsw/s Start perf stat with cgroup: $ perf stat -e cycles,cycles -A -a -G test -C 1 -- sleep 10 Run pong outside the cgroup: $ /pong Both processes pinned to CPU1, running for 10s 10687.80 ctxsw/s The penalty is now less than 2%. And the results for perf stat are correct: $ perf stat -e cycles,cycles -A -a -G test -C 1 -- sleep 10 Performance counter stats for 'sleep 10': CPU1 <not counted> cycles test # 0.000 GHz CPU1 23,933,981,448 cycles # 0.000 GHz Now perf stat reports the correct counts for for the non cgroup event. If we run pong inside the cgroup, then we also get the correct counts: $ perf stat -e cycles,cycles -A -a -G test -C 1 -- sleep 10 Performance counter stats for 'sleep 10': CPU1 22,297,726,205 cycles test # 0.000 GHz CPU1 23,933,981,448 cycles # 0.000 GHz 10.001457237 seconds time elapsed Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110825135803.GA4697@quad Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-07-21perf: Remove perf_event_attr::type checkLin Ming
PMU type id can be allocated dynamically, so perf_event_attr::type check when copying attribute from userspace to kernel is not valid. Signed-off-by: Lin Ming <ming.m.lin@intel.com> Cc: Robert Richter <robert.richter@amd.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1309421396-17438-4-git-send-email-ming.m.lin@intel.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-07-01perf: export perf_event_refresh() to modulesAvi Kivity
KVM needs one-shot samples, since a PMC programmed to -X will fire after X events and then again after 2^40 events (i.e. variable period). Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1309362157-6596-4-git-send-email-avi@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-07-01perf: Add context field to perf_eventAvi Kivity
The perf_event overflow handler does not receive any caller-derived argument, so many callers need to resort to looking up the perf_event in their local data structure. This is ugly and doesn't scale if a single callback services many perf_events. Fix by adding a context parameter to perf_event_create_kernel_counter() (and derived hardware breakpoints APIs) and storing it in the perf_event. The field can be accessed from the callback as event->overflow_handler_context. All callers are updated. Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1309362157-6596-2-git-send-email-avi@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-07-01perf: Remove the perf_output_begin(.sample) argumentPeter Zijlstra
Since only samples call perf_output_sample() its much saner (and more correct) to put the sample logic in there than in the perf_output_begin()/perf_output_end() pair. Saves a useless argument, reduces conditionals and shrinks struct perf_output_handle, win! Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-2crpvsx3cqu67q3zqjbnlpsc@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-07-01perf: Remove the nmi parameter from the swevent and overflow interfacePeter Zijlstra
The nmi parameter indicated if we could do wakeups from the current context, if not, we would set some state and self-IPI and let the resulting interrupt do the wakeup. For the various event classes: - hardware: nmi=0; PMI is in fact an NMI or we run irq_work_run from the PMI-tail (ARM etc.) - tracepoint: nmi=0; since tracepoint could be from NMI context. - software: nmi=[0,1]; some, like the schedule thing cannot perform wakeups, and hence need 0. As one can see, there is very little nmi=1 usage, and the down-side of not using it is that on some platforms some software events can have a jiffy delay in wakeup (when arch_irq_work_raise isn't implemented). The up-side however is that we can remove the nmi parameter and save a bunch of conditionals in fast paths. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Michael Cree <mcree@orcon.net.nz> Cc: Will Deacon <will.deacon@arm.com> Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com> Cc: Anton Blanchard <anton@samba.org> Cc: Eric B Munson <emunson@mgebm.net> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: David S. Miller <davem@davemloft.net> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Don Zickus <dzickus@redhat.com> Link: http://lkml.kernel.org/n/tip-agjev8eu666tvknpb3iaj0fg@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-07-01events: Ensure that timers are updated without requiring read() callEric B Munson
The event tracing infrastructure exposes two timers which should be updated each time the value of the counter is updated. Currently, these counters are only updated when userspace calls read() on the fd associated with an event. This means that counters which are read via the mmap'd page exclusively never have their timers updated. This patch adds ensures that the timers are updated each time the values in the mmap'd page are updated. Signed-off-by: Eric B Munson <emunson@mgebm.net> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1308932786-5111-1-git-send-email-emunson@mgebm.net Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-07-01events: Move lockless timer calculation into helper functionEric B Munson
Take the timer calculation from perf_output_read and move it to a helper function for any place that needs timer values but cannot take the ctx->lock. Signed-off-by: Eric B Munson <emunson@mgebm.net> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1308861279-15216-2-git-send-email-emunson@mgebm.net Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-07-01events: Add note to update_event_times comment about holding ctx->lockEric B Munson
Signed-off-by: Eric B Munson <emunson@mgebm.net> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1308861279-15216-1-git-send-email-emunson@mgebm.net Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-07-01perf_events: Fix perf buffer watermark settingVince Weaver
Since 2.6.36 (specifically commit d57e34fdd60b ("perf: Simplify the ring-buffer logic: make perf_buffer_alloc() do everything needed"), the perf_buffer_init_code() has been mis-setting the buffer watermark if perf_event_attr.wakeup_events has a non-zero value. This is because perf_event_attr.wakeup_events is a union with perf_event_attr.wakeup_watermark. This commit re-enables the check for perf_event_attr.watermark being set before continuing with setting a non-default watermark. This bug is most noticable when you are trying to use PERF_IOC_REFRESH with a value larger than one and perf_event_attr.wakeup_events is set to one. In this case the buffer watermark will be set to 1 and you will get extraneous POLL_IN overflows rather than POLL_HUP as expected. [ avoid using attr.wakeup_events when attr.watermark is set ] Signed-off-by: Vince Weaver <vweaver1@eecs.utk.edu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: <stable@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.00.1106011506390.5384@cl320.eecs.utk.edu Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-06-09perf: Split up buffer handling from core codeFrederic Weisbecker
And create the internal perf events header. v2: Keep an internal inlined perf_output_copy() Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Borislav Petkov <bp@alien8.de> Cc: Stephane Eranian <eranian@google.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1305827704-5607-1-git-send-email-fweisbec@gmail.com [ v3: use clearer 'ring_buffer' and 'rb' naming ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-06-07perf, core: Fix initial task_ctx/event installationPeter Zijlstra
A lost Quilt refresh of 2c29ef0fef8 (perf: Simplify and fix __perf_install_in_context()) is causing grief and lockups, reported by Jiri Olsa. When installing an event in a task context, there's a number of issues: - there might not be an existing task context, in which case we should install the now current context; - there might already be a context, not the current one, in which case we should de-schedule the old and install the new; these cases were dealt with in the lost refresh, however there is one further case that was found in testing: - there might already be a context, the current one, in which case we should still de-schedule, and should take care to re-install it (note that task_ctx_sched_out() clears cpuctx->task_ctx). Reported-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1307399008.2497.971.camel@laptop Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-06-04Merge branch 'perf/urgent' into perf/coreIngo Molnar
Conflicts: tools/perf/util/python.c Merge reason: resolve the conflict with perf/urgent. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-06-04Merge branch 'perf/urgent' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent
2011-05-31perf, cgroups: Fix up for new APIPeter Zijlstra
Ben changed the cgroup API in commit f780bdb7c1c (cgroups: add per-thread subsystem callbacks) in an incompatible way, but forgot to convert the perf cgroup bits. Avoid compile warnings and runtime splats and convert perf too ;-) Acked-by: Ben Blum <bblum@andrew.cmu.edu> Cc: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1306767651.1200.2990.camel@twins Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-28perf: De-schedule a task context when removing the last eventPeter Zijlstra
Since perf_install_in_context() will now install a context when we add the first event, we can de-schedule the context when the last event is removed. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110409192142.090431763@chello.nl Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-28perf: Change close() semantics for group eventsPeter Zijlstra
In order to always call list_del_event() on the correct cpu if the event is part of an active context and avoid having to do two IPIs, change the close() semantics slightly. The current perf_event_disable() call would disable a whole group if the event that's being closed is the group leader, whereas the new code keeps the group siblings enabled. People should not rely on this behaviour and I don't think they do, but in case we find they do, the fix is easy and we have to take the double IPI cost. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vince Weaver <vweaver1@eecs.utk.edu> Link: http://lkml.kernel.org/r/20110409192142.038377551@chello.nl Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-28perf: Collect the schedule-in rules in one functionPeter Zijlstra
This was scattered out - refactor it into a single function. No change in functionality. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110409192141.979862055@chello.nl Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-28perf: Change and simplify ctx::is_active semanticsPeter Zijlstra
Instead of tracking if a context is active or not, track which events of the context are active. By making it a bitmask of EVENT_PINNED|EVENT_FLEXIBLE we can simplify some of the scheduling routines since it can avoid adding events that are already active. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110409192141.930282378@chello.nl Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-28perf: Simplify and fix __perf_install_in_context()Peter Zijlstra
Currently __perf_install_in_context() will try and schedule in the event irrespective of our event scheduling rules, that is, we try to schedule CPU-pinned, TASK-pinned, CPU-flexible, TASK-flexible, but when creating a new event we simply try and schedule it on top of whatever is already on the PMU, this can lead to errors for pinned events. Therefore, simplify things and simply schedule everything out, add the event to the corresponding context and schedule everything back in. This also nicely handles the case where with __ARCH_WANT_INTERRUPTS_ON_CTXSW the IPI can come right in the middle of schedule, before we managed to call perf_event_task_sched_in(). Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110409192141.870894224@chello.nl Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-28perf: Remove task_ctx_sched_in()Peter Zijlstra
Make task_ctx_sched_*() imply EVENT_ALL, since anything less will not actually have scheduled the task in/out at all. Since there's no site that schedules all of a task in (due to the interleave with flexible cpuctx) we can remove this function. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110409192141.817893268@chello.nl Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-28perf: Optimize event scheduling lockingPeter Zijlstra
Currently we only hold one ctx->lock at a time, which results in us flipping back and forth between cpuctx->ctx.lock and task_ctx->lock. Avoid this and gain large atomic regions by holding both locks. We nest the task lock inside the cpu lock, since with task scheduling we might have to change task ctx while holding the cpu ctx lock. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110409192141.769881865@chello.nl Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-28perf: Clean up 'ctx' reference countingPeter Zijlstra
Small cleanup to how we refcount in find_get_context(), this also allows us to use put_ctx() to free things instead of using kfree(). Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110409192141.719340481@chello.nl Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-28perf: Optimize ctx_sched_out()Peter Zijlstra
Oleg noted that ctx_sched_out() disables the PMU even though it might not actually do something, avoid needless PMU-disabling. Reported-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110409192141.665385503@chello.nl Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-28perf: Fix SIGIO handlingPeter Zijlstra
Vince noticed that unless we mmap() a buffer, SIGIO gets lost. So explicitly push the wakeup (including signals) when requested. Reported-by: Vince Weaver <vweaver1@eecs.utk.edu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: <stable@kernel.org> Link: http://lkml.kernel.org/n/tip-2euus3f3x3dyvdk52cjxw8zu@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-19Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (78 commits) Revert "rcu: Decrease memory-barrier usage based on semi-formal proof" net,rcu: convert call_rcu(prl_entry_destroy_rcu) to kfree batman,rcu: convert call_rcu(softif_neigh_free_rcu) to kfree_rcu batman,rcu: convert call_rcu(neigh_node_free_rcu) to kfree() batman,rcu: convert call_rcu(gw_node_free_rcu) to kfree_rcu net,rcu: convert call_rcu(kfree_tid_tx) to kfree_rcu() net,rcu: convert call_rcu(xt_osf_finger_free_rcu) to kfree_rcu() net/mac80211,rcu: convert call_rcu(work_free_rcu) to kfree_rcu() net,rcu: convert call_rcu(wq_free_rcu) to kfree_rcu() net,rcu: convert call_rcu(phonet_device_rcu_free) to kfree_rcu() perf,rcu: convert call_rcu(swevent_hlist_release_rcu) to kfree_rcu() perf,rcu: convert call_rcu(free_ctx) to kfree_rcu() net,rcu: convert call_rcu(__nf_ct_ext_free_rcu) to kfree_rcu() net,rcu: convert call_rcu(net_generic_release) to kfree_rcu() net,rcu: convert call_rcu(netlbl_unlhsh_free_addr6) to kfree_rcu() net,rcu: convert call_rcu(netlbl_unlhsh_free_addr4) to kfree_rcu() security,rcu: convert call_rcu(sel_netif_free) to kfree_rcu() net,rcu: convert call_rcu(xps_dev_maps_release) to kfree_rcu() net,rcu: convert call_rcu(xps_map_release) to kfree_rcu() net,rcu: convert call_rcu(rps_map_release) to kfree_rcu() ...
2011-05-04perf events: Clean up definitions and initializers, update copyrightsIngo Molnar
Fix a few inconsistent style bits that were added over the past few months. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-yv4hwf9yhnzoada8pcpb3a97@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-03hw breakpoints: Move to kernel/events/Borislav Petkov
As part of the events sybsystem unification, relocate hw_breakpoint.c into its new destination. Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-05-03perf: Start the restructuringBorislav Petkov
mv kernel/perf_event.c -> kernel/events/core.c. From there, all further sensible splitting can happen. The idea is that due to perf_event.c becoming pretty sizable and with the advent of the marriage with ftrace, splitting functionality into its logical parts should help speeding up the unification and to manage the complexity of the subsystem. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>