- 11 Mar, 2010 2 commits
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Arnaldo Carvalho de Melo authored
[acme@mica linux-2.6-tip]$ perf record -a -f Fatal: Permission error - are you root? Consider tweaking /proc/sys/kernel/perf_event_paranoid. [acme@mica linux-2.6-tip]$ Suggested-by:
Ingo Molnar <mingo@elte.hu> Signed-off-by:
Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <1268333592-30872-2-git-send-email-acme@infradead.org> Signed-off-by:
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eranian@google.com authored
This patch is an optimization in perf_event_task_sched_in() to avoid scheduling the events twice in a row. Without it, the perf_disable()/perf_enable() pair is invoked twice, thereby pinned events counts while scheduling flexible events and we go throuh hw_perf_enable() twice. By encapsulating, the whole sequence into perf_disable()/perf_enable() we ensure, hw_perf_enable() is going to be invoked only once because of the refcount protection. Signed-off-by:
Stephane Eranian <eranian@google.com> Signed-off-by:
Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1268288765-5326-1-git-send-email-eranian@google.com> Signed-off-by:
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- 10 Mar, 2010 38 commits
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Ingo Molnar authored
Fix typo. But the modularization here is ugly and should be improved. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <new-submission> Signed-off-by: -
Ingo Molnar authored
The PEBS+LBR decoding magic needs the insn_get_length() infrastructure to be able to decode x86 instruction length. So split it out of KPROBES dependency and make it enabled when either KPROBES or PERF_EVENTS is enabled. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Masami Hiramatsu <mhiramat@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <new-submission> Signed-off-by: -
Peter Zijlstra authored
Don't decrement the TOS twice... Signed-off-by:
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Peter Zijlstra authored
Pull the core handler in line with the nhm one, also make sure we always drain the buffer. Signed-off-by:
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Peter Zijlstra authored
We don't need checking_{wr,rd}msr() calls, since we should know what cpu we're running on and not use blindly poke at msrs. Signed-off-by: -
Peter Zijlstra authored
If we reset the LBR on each first counter, simple counter rotation which first deschedules all counters and then reschedules the new ones will lead to LBR reset, even though we're still in the same task context. Reduce this by not flushing on the first counter but only flushing on different task contexts. Signed-off-by:
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Peter Zijlstra authored
We need to use the actual cpuc->pebs_enabled value, not a local copy for the changes to take effect. Signed-off-by:
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Peter Zijlstra authored
Its unclear if the PEBS state record will have only a single bit set, in case it does not and accumulates bits, deal with that by only processing each event once. Also, robustify some of the code. Signed-off-by:
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Peter Zijlstra authored
The documentation says we have to enable PEBS before we enable the PMU proper. Signed-off-by:
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Peter Zijlstra authored
We should never call ->enable with the pmu enabled, and we _can_ have ->disable called with the pmu enabled. Signed-off-by:
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Peter Zijlstra authored
We should never call ->enable with the pmu enabled, and we _can_ have ->disable called with the pmu enabled. Signed-off-by:
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Peter Zijlstra authored
I overlooked the perf_disable()/perf_enable() calls in intel_pmu_handle_irq(), (pointed out by Markus) so we should not explicitly disable_all/enable_all pebs counters in the drain functions, these are already disabled and enabling them early is confusing. Signed-off-by:
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Peter Zijlstra authored
Calling ioctl(PERF_EVENT_IOC_DISABLE) on a thottled counter would result in a double disable, cure this by using x86_pmu_{start,stop} for throttle/unthrottle and teach x86_pmu_stop() to check ->active_mask. Signed-off-by: -
Peter Zijlstra authored
It turns out the LBR is massively unreliable on certain CPUs, so code the fixup a little more defensive to avoid crashing the kernel. Signed-off-by:
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Peter Zijlstra authored
Some CPUs have errata where the LBR is not cleared on Power-On. So always clear the LBRs before use. Signed-off-by:
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Peter Zijlstra authored
This CPU has just too many handycaps to be really useful. Signed-off-by:
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Peter Zijlstra authored
Fix up the ds allocation error path, where we could free @buffer before we used it. Signed-off-by:
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Peter Zijlstra authored
Since there's now two users for this, place it in a common header. Signed-off-by:
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Peter Zijlstra authored
Expose the full PEBS record using PERF_SAMPLE_RAW Signed-off-by:
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Peter Zijlstra authored
Saner PERF_CAPABILITIES support, which also exposes pebs_trap. Use that latter to make PEBS's use of LBR conditional since a fault-like pebs should already report the correct IP. ( As of this writing there is no known hardware that implements !pebs_trap ) Signed-off-by:
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Peter Zijlstra authored
Use the PERF_RECORD_MISC_EXACT information to measure the success rate of the PEBS fix-up. Signed-off-by:
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Peter Zijlstra authored
Use the LBR to fix up the PEBS IP+1 issue. As said, PEBS reports the next instruction, here we use the LBR to find the last branch and from that construct the actual IP. If the IP matches the LBR-TO, we use LBR-FROM, otherwise we use the LBR-TO address as the beginning of the last basic block and decode forward. Once we find a match to the current IP, we use the previous location. This patch introduces a new ABI element: PERF_RECORD_MISC_EXACT, which conveys that the reported IP (PERF_SAMPLE_IP) is the exact instruction that caused the event (barring CPU errata). The fixup can fail due to various reasons: 1) LBR contains invalid data (quite possible) 2) part of the basic block got paged out 3) the reported IP isn't part of the basic block (see 1) Signed-off-by:
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Peter Zijlstra authored
Implement simple suport Intel Last-Branch-Record, it supports all hardware that implements FREEZE_LBRS_ON_PMI, but does not (yet) implement the LBR config register. The Intel LBR is a FIFO of From,To addresses describing the last few branches the hardware took. This patch does not add perf interface to the LBR, but merely provides an interface for internal use. Signed-off-by:
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Peter Zijlstra authored
Minimal userspace interface to the new 'precise' events flag. Can be used like "perf top -e r00c0p" which will use PEBS to sample retired instructions. Signed-off-by:
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Peter Zijlstra authored
This patch implements support for Intel Precise Event Based Sampling, which is an alternative counter mode in which the counter triggers a hardware assist to collect information on events. The hardware assist takes a trap like snapshot of a subset of the machine registers. This data is written to the Intel Debug-Store, which can be programmed with a data threshold at which to raise a PMI. With the PEBS hardware assist being trap like, the reported IP is always one instruction after the actual instruction that triggered the event. This implements a simple PEBS model that always takes a single PEBS event at a time. This is done so that the interaction with the rest of the system is as expected (freq adjust, period randomization, lbr, callchains, etc.). It adds an ABI element: perf_event_attr::precise, which indicates that we wish to use this (constrained, but precise) mode. Signed-off-by:
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Peter Zijlstra authored
Try to avoid useless rotation and PMU disables. [ Could be improved by keeping a nr_runnable count to better account for the < PERF_STAT_INACTIVE counters ] Signed-off-by:
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Peter Zijlstra authored
hw_perf_enable() would enable already enabled events. This causes problems with code that assumes that ->enable/->disable calls are balanced (like the LBR code does). What happens is that events that were already running and left in place would get enabled again. Avoid this by only enabling new events that match their previous assignment. Signed-off-by:
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Peter Zijlstra authored
hw_perf_enable() would disable events that were not yet enabled. This causes problems with code that assumes that ->enable/->disable calls are balanced (like the LBR code does). What happens is that we disable newly added counters that match their previous assignment, even though they are not yet programmed on the hardware. Avoid this by only doing the first pass over the existing events. Signed-off-by:
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Peter Zijlstra authored
Make sure n_added is properly accounted so that we can rely on the value to reflect the number of added counters. This is needed if its going to be used for more than a boolean check. Signed-off-by:
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Peter Zijlstra authored
Calling ioctl(PERF_EVENT_IOC_DISABLE) on a thottled counter would result in a double disable, cure this by using x86_pmu_{start,stop} for throttle/unthrottle and teach x86_pmu_stop() to check ->active_mask. Signed-off-by: -
Peter Zijlstra authored
pmu::start should undo pmu::stop, make it so. Signed-off-by:
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Peter Zijlstra authored
There is no concurrency on these variables, so don't use LOCK'ed ops. As to the intel_pmu_handle_irq() status bit clean, nobody uses that so remove it all together. Signed-off-by:
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Peter Zijlstra authored
Pass the full perf_event into the x86_pmu functions so that those may make use of more than the hw_perf_event, and while doing this, remove the superfluous second argument. Signed-off-by:
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Peter Zijlstra authored
The second and third argument to x86_perf_event_update() are superfluous since they are simple expressions of the first argument. Hence remove them. Signed-off-by:
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Peter Zijlstra authored
The second and third argument to x86_perf_event_set_period() are superfluous since they are simple expressions of the first argument. Hence remove them. Signed-off-by:
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Peter Zijlstra authored
Explicitly use intel_pmu_{disable,enable}_all() in intel_pmu_handle_irq() to avoid the NMI race conditions in perf_{disable,enable} Signed-off-by: -
Peter Zijlstra authored
Currently we always call hw_perf_disable(), even if its already disabled, this seems superflous, esp. since it cannot be made NMI safe (see further patches). Signed-off-by:
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Peter Zijlstra authored
Remove the hw_perf_event_*() hotplug hooks in favour of per PMU hotplug notifiers. This has the advantage of reducing the static weak interface as well as exposing all hotplug actions to the PMU. Use this to fix x86 hotplug usage where we did things in ONLINE which should have been done in UP_PREPARE or STARTING. Signed-off-by:
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