Intel PT cannot be used at the same time as LBR or BTS and will cause a
general protection fault if they are used together. In order to avoid
fixing up GPs in the fast path, instead we disallow creating LBR/BTS
events when PT events are present and vice versa.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kaixu Xia <kaixu.xia@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@infradead.org
Cc: adrian.hunter@intel.com
Cc: kan.liang@intel.com
Cc: markus.t.metzger@intel.com
Cc: mathieu.poirier@linaro.org
Link: http://lkml.kernel.org/r/1421237903-181015-12-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
On Broadwell INST_RETIRED.ALL cannot be used with any period
that doesn't have the lowest 6 bits cleared. And the period
should not be smaller than 128.
This is erratum BDM11 and BDM55:
http://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/5th-gen-core-family-spec-update.pdf
BDM11: When using a period < 100; we may get incorrect PEBS/PMI
interrupts and/or an invalid counter state.
BDM55: When bit0-5 of the period are !0 we may get redundant PEBS
records on overflow.
Add a new callback to enforce this, and set it for Broadwell.
How does this handle the case when an app requests a specific
period with some of the bottom bits set?
Short answer:
Any useful instruction sampling period needs to be 4-6 orders
of magnitude larger than 128, as an PMI every 128 instructions
would instantly overwhelm the system and be throttled.
So the +-64 error from this is really small compared to the
period, much smaller than normal system jitter.
Long answer (by Peterz):
IFF we guarantee perf_event_attr::sample_period >= 128.
Suppose we start out with sample_period=192; then we'll set period_left
to 192, we'll end up with left = 128 (we truncate the lower bits). We
get an interrupt, find that period_left = 64 (>0 so we return 0 and
don't get an overflow handler), up that to 128. Then we trigger again,
at n=256. Then we find period_left = -64 (<=0 so we return 1 and do get
an overflow). We increment with sample_period so we get left = 128. We
fire again, at n=384, period_left = 0 (<=0 so we return 1 and get an
overflow). And on and on.
So while the individual interrupts are 'wrong' we get then with
interval=256,128 in exactly the right ratio to average out at 192. And
this works for everything >=128.
So the num_samples*fixed_period thing is still entirely correct +- 127,
which is good enough I'd say, as you already have that error anyhow.
So no need to 'fix' the tools, al we need to do is refuse to create
INST_RETIRED:ALL events with sample_period < 128.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
[ Updated comments and changelog a bit. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1424225886-18652-3-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With LBR call stack feature enable, there are three callchain options.
Enable the 3rd callchain option (LBR callstack) to user space tooling.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-api@vger.kernel.org
Link: http://lkml.kernel.org/r/20141105093759.GQ10501@worktop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When the LBR call stack is enabled, it is necessary to save/restore
the LBR stack on context switch. We can use pmu specific data to
store LBR stack when task is scheduled out. This patch adds code
that allocates the pmu specific data.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Stephane Eranian <eranian@google.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: jolsa@redhat.com
Link: http://lkml.kernel.org/r/1415156173-10035-8-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Haswell has a new feature that utilizes the existing LBR facility to
record call chains. To enable this feature, bits (JCC, NEAR_IND_JMP,
NEAR_REL_JMP, FAR_BRANCH, EN_CALLSTACK) in LBR_SELECT must be set to 1,
bits (NEAR_REL_CALL, NEAR-IND_CALL, NEAR_RET) must be cleared. Due to
a hardware bug of Haswell, this feature doesn't work well with
FREEZE_LBRS_ON_PMI.
When the call stack feature is enabled, the LBR stack will capture
unfiltered call data normally, but as return instructions are executed,
the last captured branch record is flushed from the on-chip registers
in a last-in first-out (LIFO) manner. Thus, branch information relative
to leaf functions will not be captured, while preserving the call stack
information of the main line execution path.
This patch defines a separate lbr_sel map for Haswell. The map contains
a new entry for the call stack feature.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: eranian@google.com
Cc: jolsa@redhat.com
Link: http://lkml.kernel.org/r/1415156173-10035-5-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Previous commit introduces context switch callback, its function
overlaps with the flush branch stack callback. So we can use the
context switch callback to flush LBR stack.
This patch adds code that uses the flush branch callback to
flush the LBR stack when task is being scheduled in. The callback
is enabled only when there are events use the LBR hardware. This
patch also removes all old flush branch stack code.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: eranian@google.com
Cc: jolsa@redhat.com
Link: http://lkml.kernel.org/r/1415156173-10035-4-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The callback is invoked when process is scheduled in or out.
It provides mechanism for later patches to save/store the LBR
stack. For the schedule in case, the callback is invoked at
the same place that flush branch stack callback is invoked.
So it also can replace the flush branch stack callback. To
avoid unnecessary overhead, the callback is enabled only when
there are events use the LBR stack.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: eranian@google.com
Cc: jolsa@redhat.com
Link: http://lkml.kernel.org/r/1415156173-10035-3-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The index of lbr_sel_map is bit value of perf branch_sample_type.
PERF_SAMPLE_BRANCH_MAX is 1024 at present, so each lbr_sel_map uses
4096 bytes. By using bit shift as index, we can reduce lbr_sel_map
size to 40 bytes. This patch defines 'bit shift' for branch types,
and use 'bit shift' to define lbr_sel_maps.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Stephane Eranian <eranian@google.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: jolsa@redhat.com
Cc: linux-api@vger.kernel.org
Link: http://lkml.kernel.org/r/1415156173-10035-2-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We currently allow any process to use rdpmc. This significantly
weakens the protection offered by PR_TSC_DISABLED, and it could be
helpful to users attempting to exploit timing attacks.
Since we can't enable access to individual counters, use a very
coarse heuristic to limit access to rdpmc: allow access only when
a perf_event is mmapped. This protects seccomp sandboxes.
There is plenty of room to further tighen these restrictions. For
example, this allows rdpmc for any x86_pmu event, but it's only
useful for self-monitoring tasks.
As a side effect, cap_user_rdpmc will now be false for AMD uncore
events. This isn't a real regression, since .event_idx is disabled
for these events anyway for the time being. Whenever that gets
re-added, the cap_user_rdpmc code can be adjusted or refactored
accordingly.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Vince Weaver <vince@deater.net>
Cc: "hillf.zj" <hillf.zj@alibaba-inc.com>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/a2bdb3cf3a1d70c26980d7c6dddfbaa69f3182bf.1414190806.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add a FLAGS_UEVENT_CONSTRAINT macro that allows us to
match on event+umask, and in additional all flags.
This is needed to ensure the INV and CMASK fields
are zero for specific events, as this can cause undefined
behavior.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Maria Dimakopoulou <maria.n.dimakopoulou@gmail.com>
Cc: Mark Davies <junk@eslaf.co.uk>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1411569288-5627-1-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
These patches:
86a349a28b ("perf/x86/intel: Add Broadwell core support")
c46e665f03 ("perf/x86: Add INST_RETIRED.ALL workarounds")
fdda3c4aac ("perf/x86/intel: Use Broadwell cache event list for Haswell")
introduced magic constants and unexplained changes:
https://lkml.org/lkml/2014/10/28/1128https://lkml.org/lkml/2014/10/27/325https://lkml.org/lkml/2014/8/27/546https://lkml.org/lkml/2014/10/28/546
Peter Zijlstra has attempted to help out, to clean up the mess:
https://lkml.org/lkml/2014/10/28/543
But has not received helpful and constructive replies which makes
me doubt wether it can all be finished in time until v3.18 is
released.
Despite various review feedback the author (Andi Kleen) has answered
only few of the review questions and has generally been uncooperative,
only giving replies when prompted repeatedly, and only giving minimal
answers instead of constructively explaining and helping along the effort.
That kind of behavior is not acceptable.
There's also a boot crash on Intel E5-1630 v3 CPUs reported for another
commit from Andi Kleen:
e735b9db12 ("perf/x86/intel/uncore: Add Haswell-EP uncore support")
https://lkml.org/lkml/2014/10/22/730
Which is not yet resolved. The uncore driver is independent in theory,
but the crash makes me worry about how well all these patches were
tested and makes me uneasy about the level of interminging that the
Broadwell and Haswell code has received by the commits above.
As a first step to resolve the mess revert the Broadwell client commits
back to the v3.17 version, before we run out of time and problematic
code hits a stable upstream kernel.
( If the Haswell-EP crash is not resolved via a simple fix then we'll have
to revert the Haswell-EP uncore driver as well. )
The Broadwell client series has to be submitted in a clean fashion, with
single, well documented changes per patch. If they are submitted in time
and are accepted during review then they can possibly go into v3.19 but
will need additional scrutiny due to the rocky history of this patch set.
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: eranian@google.com
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409683455-29168-3-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
On Broadwell INST_RETIRED.ALL cannot be used with any period
that doesn't have the lowest 6 bits cleared. And the period
should not be smaller than 128.
Add a new callback to enforce this, and set it for Broadwell.
This is erratum BDM57 and BDM11.
How does this handle the case when an app requests a specific
period with some of the bottom bits set
The apps thinks it is sampling at X occurences per sample, when it is
in fact at X - 63 (worst case).
Short answer:
Any useful instruction sampling period needs to be 4-6 orders
of magnitude larger than 128, as an PMI every 128 instructions
would instantly overwhelm the system and be throttled.
So the +-64 error from this is really small compared to the
period, much smaller than normal system jitter.
Long answer:
<write up by Peter:>
IFF we guarantee perf_event_attr::sample_period >= 128.
Suppose we start out with sample_period=192; then we'll set period_left
to 192, we'll end up with left = 128 (we truncate the lower bits). We
get an interrupt, find that period_left = 64 (>0 so we return 0 and
don't get an overflow handler), up that to 128. Then we trigger again,
at n=256. Then we find period_left = -64 (<=0 so we return 1 and do get
an overflow). We increment with sample_period so we get left = 128. We
fire again, at n=384, period_left = 0 (<=0 so we return 1 and get an
overflow). And on and on.
So while the individual interrupts are 'wrong' we get then with
interval=256,128 in exactly the right ratio to average out at 192. And
this works for everything >=128.
So the num_samples*fixed_period thing is still entirely correct +- 127,
which is good enough I'd say, as you already have that error anyhow.
So no need to 'fix' the tools, al we need to do is refuse to create
INST_RETIRED:ALL events with sample_period < 128.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Maria Dimakopoulou <maria.n.dimakopoulou@gmail.com>
Cc: Mark Davies <junk@eslaf.co.uk>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1409683455-29168-4-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The basic idea is that it does not make sense to list all PEBS
events individually. The list is very long, sometimes outdated
and the hardware doesn't need it. If an event does not support
PEBS it will just not count, there is no security issue.
We need to only list events that something special, like
supporting load or store addresses.
This vastly simplifies the PEBS event selection. It also
speeds up the scheduling because the scheduler doesn't
have to walk as many constraints.
Bugs fixed:
- We do not allow setting forbidden flags with PEBS anymore
(SDM 18.9.4), except for the special cycle event.
This is done using a new constraint macro that also
matches on the event flags.
- Correct DataLA and load/store/na flags reporting on Haswell
[Requires a followon patch]
- We did not allow all PEBS events on Haswell:
We were missing some valid subevents in d1-d2 (MEM_LOAD_UOPS_RETIRED.*,
MEM_LOAD_UOPS_RETIRED_L3_HIT_RETIRED.*)
This includes the changes proposed by Stephane earlier and obsoletes
his patchkit (except for some changes on pre Sandy Bridge/Silvermont
CPUs)
I only did Sandy Bridge and Silvermont and later so far, mostly because these
are the parts I could directly confirm the hardware behavior with hardware
architects. Also I do not believe the older CPUs have any
missing events in their PEBS list, so there's no pressing
need to change them.
I did not implement the flag proposed by Peter to allow
setting forbidden flags. If really needed this could
be implemented on to of this patch.
v2: Fix broken store events on SNB/IVB (Stephane Eranian)
v3: More fixes. Rename some arguments (Stephane Eranian)
v4: List most Haswell events individually again to report
memory operation type correctly.
Add new flags to describe load/store/na for datala.
Update description.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1407785233-32193-2-git-send-email-eranian@google.com
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maria Dimakopoulou <maria.n.dimakopoulou@gmail.com>
Cc: Mark Davies <junk@eslaf.co.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With -cpu host, KVM reports LBR and extra_regs support, if the host has
support.
When the guest perf driver tries to access LBR or extra_regs MSR,
it #GPs all MSR accesses,since KVM doesn't handle LBR and extra_regs support.
So check the related MSRs access right once at initialization time to avoid
the error access at runtime.
For reproducing the issue, please build the kernel with CONFIG_KVM_INTEL = y
(for host kernel).
And CONFIG_PARAVIRT = n and CONFIG_KVM_GUEST = n (for guest kernel).
Start the guest with -cpu host.
Run perf record with --branch-any or --branch-filter in guest to trigger LBR
Run perf stat offcore events (E.g. LLC-loads/LLC-load-misses ...) in guest to
trigger offcore_rsp #GP
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maria Dimakopoulou <maria.n.dimakopoulou@gmail.com>
Cc: Mark Davies <junk@eslaf.co.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Yan, Zheng <zheng.z.yan@intel.com>
Link: http://lkml.kernel.org/r/1405365957-20202-1-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add a few comments on the ->add(), ->del() and ->*_txn()
implementation.
Requested-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-he3819318c245j7t5e1e22tr@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The EVENT_CONSTRAINT_END() macro defines the end marker as
a constraint with a weight of zero. This was all fine
until we blacklisted the corrupting memory events on
Intel IvyBridge. These events are blacklisted by using
a counter bitmask of zero. Thus, they also get a constraint
weight of zero.
The iteration macro: for_each_constraint tests the weight==0.
Therefore, it was stopping at the first blacklisted event, i.e.,
0xd0. The corrupting events were therefore considered as
unconstrained and were scheduled on any of the generic counters.
This patch fixes the end marker to have a weight of -1. With
this, the blacklisted events get an empty constraint and cannot
be scheduled which is what we want for now.
Signed-off-by: Maria Dimakopoulou <maria.n.dimakopoulou@gmail.com>
Reviewed-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: ak@linux.intel.com
Cc: jolsa@redhat.com
Cc: zheng.z.yan@intel.com
Link: http://lkml.kernel.org/r/20131204232437.GA10689@starlight
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Haswell always give an extra LBR record after every TSX abort.
Suppress the extra record.
This only works when the abort is visible in the LBR
If the original abort has already left the 16 LBR entries
the extra entry will will stay.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1379688044-14173-7-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Clean up the weird CP interrupt exception code by keeping a CP mask.
Andi suggested this implementation but weirdly didn't actually
implement it himself, do so now because it removes the conditional in
the interrupt handler and avoids the assumption its only on cnt2.
Suggested-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-dvb4q0rydkfp00kqat4p5bah@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Compared to old atom, Silvermont has offcore and has more events
that support PEBS.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1374138144-17278-2-git-send-email-zheng.z.yan@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch fixes a problem with the shared registers mutual
exclusion code and incremental event scheduling by the
generic perf_event code.
There was a bug whereby the mutual exclusion on the shared
registers was not enforced because of incremental scheduling
abort due to event constraints. As an example on Intel
Nehalem, consider the following events:
group1= L1D_CACHE_LD:E_STATE,OFFCORE_RESPONSE_0:PF_RFO,L1D_CACHE_LD:I_STATE
group2= L1D_CACHE_LD:I_STATE
The L1D_CACHE_LD event can only be measured by 2 counters. Yet, there
are 3 instances here. The first group can be scheduled and is committed.
Then, the generic code tries to schedule group2 and this fails (because
there is no more counter to support the 3rd instance of L1D_CACHE_LD).
But in x86_schedule_events() error path, put_event_contraints() is invoked
on ALL the events and not just the ones that just failed. That causes the
"lock" on the shared offcore_response MSR to be released. Yet the first group
is actually scheduled and is exposed to reprogramming of that shared msr by
the sibling HT thread. In other words, there is no guarantee on what is
measured.
This patch fixes the problem by tagging committed events with the
PERF_X86_EVENT_COMMITTED tag. In the error path of x86_schedule_events(),
only the events NOT tagged have their constraint released. The tag
is eventually removed when the event in descheduled.
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130620164254.GA3556@quad
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Recent Intel CPUs like Haswell and IvyBridge have a new
alternative MSR range for perfctrs that allows writing the full
counter width. Enable this range if the hardware reports it
using a new capability bit.
Currently the perf code queries CPUID to get the counter width,
and sign extends the counter values as needed. The traditional
PERFCTR MSRs always limit to 32bit, even though the counter
internally is larger (usually 48 bits on recent CPUs)
When the new capability is set use the alternative range which
do not have these restrictions.
This lowers the overhead of perf stat slightly because it has to
do less interrupts to accumulate the counter value. On Haswell
it also avoids some problems with TSX aborting when the end of
the counter range is reached.
( See the patch "perf/x86/intel: Avoid checkpointed counters
causing excessive TSX aborts" for more details. )
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Stephane Eranian <eranian@google.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1372173153-20215-1-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
mem-loads is basically the same as Sandy Bridge,
but we use a separate string for changes later.
Haswell doesn't support the full precise store mode,
so we emulate it using the "DataLA" facility.
This allows to do everything, but for data sources we
can only detect L1 hit or not.
There is no explicit enable bit anymore, so we have
to tie it to a perf internal only flag.
The address is supported for all memory related PEBS
events with DataLA. Instead of only logging for the
load and store events we allow logging it for all
(it will be simply 0 if the current event does not
support it)
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Andi Kleen <ak@linux.jf.intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/r/1371515812-9646-7-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This avoids some problems with spurious PMIs on Haswell.
Haswell seems to behave more like P4 in this regard. Do
the same thing as the P4 perf handler by unmasking
the NMI only at the end. Shouldn't make any difference
for earlier family 6 cores.
(Tested on Haswell, IvyBridge, Westmere, Saltwell (Atom).)
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Andi Kleen <ak@linux.jf.intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/r/1371515812-9646-5-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add simple PEBS support for Haswell.
The constraints are similar to SandyBridge with a few new
events.
Reviewed-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Andi Kleen <ak@linux.jf.intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/r/1371515812-9646-4-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Similar to SandyBridge, but has a few new events and two
new counter bits.
There are some new counter flags that need to be prevented
from being set on fixed counters, and allowed to be set
for generic counters.
Also we add support for the counter 2 constraint to handle
all raw events.
(Contains fixes from Stephane Eranian.)
Reviewed-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Andi Kleen <ak@linux.jf.intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/r/1371515812-9646-3-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
x86_schedule_events() caches event constraints on the stack during
scheduling. Given the number of possible events, this is 512 bytes of
stack; since it can be invoked under schedule() under god-knows-what,
this is causing stack blowouts.
Trade some space usage for stack safety: add a place to cache the
constraint pointer to struct perf_event. For 8 bytes per event (1% of
its size) we can save the giant stack frame.
This shouldn't change any aspect of scheduling whatsoever and while in
theory the locality's a tiny bit worse, I doubt we'll see any
performance impact either.
Tested: `perf stat whatever` does not blow up and produces
results that aren't hugely obviously wrong. I'm not sure how to run
particularly good tests of perf code, but this should not produce any
functional change whatsoever.
Signed-off-by: Andrew Hunter <ahh@google.com>
Reviewed-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1369332423-4400-1-git-send-email-ahh@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch adds support for memory profiling using the
PEBS Load Latency facility.
Load accesses are sampled by HW and the instruction
address, data address, load latency, data source, tlb,
locked information can be saved in the sampling buffer
if using the PERF_SAMPLE_COST (for latency),
PERF_SAMPLE_ADDR, PERF_SAMPLE_DATA_SRC types.
To enable PEBS Load Latency, users have to use the
model specific event:
- on NHM/WSM: MEM_INST_RETIRED:LATENCY_ABOVE_THRESHOLD
- on SNB/IVB: MEM_TRANS_RETIRED:LATENCY_ABOVE_THRESHOLD
To make things easier, this patch also exports a generic
alias via sysfs: mem-loads. It export the right event
encoding based on the host CPU and can be used directly
by the perf tool.
Loosely based on Intel's Lin Ming patch posted on LKML
in July 2011.
Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: ak@linux.intel.com
Cc: acme@redhat.com
Cc: jolsa@redhat.com
Cc: namhyung.kim@lge.com
Link: http://lkml.kernel.org/r/1359040242-8269-9-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This patch adds a flags field to each event constraint.
It can be used to store event specific features which can
then later be used by scheduling code or low-level x86 code.
The flags are propagated into event->hw.flags during the
get_event_constraint() call. They are cleared during the
put_event_constraint() call.
This mechanism is going to be used by the PEBS-LL patches.
It avoids defining yet another table to hold event specific
information.
Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: ak@linux.intel.com
Cc: jolsa@redhat.com
Cc: namhyung.kim@lge.com
Link: http://lkml.kernel.org/r/1359040242-8269-4-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Similar to config_base and event_base, allow architecture
specific RDPMC ECX values.
Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Acked-by: Stephane Eranian <eranian@google.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1360171589-6381-6-git-send-email-jacob.shin@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Move counter index to MSR address offset calculation to
architecture specific files. This prepares the way for
perf_event_amd to enable counter addresses that are not
contiguous -- for example AMD Family 15h processors have 6 core
performance counters starting at 0xc0010200 and 4 northbridge
performance counters starting at 0xc0010240.
Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Stephane Eranian <eranian@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1360171589-6381-5-git-send-email-jacob.shin@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add support to display hardware events translations available
through the sysfs. Add 'events' group attribute under the sysfs
x86 PMU record with attribute/file for each hardware event.
This patch adds only backbone for PMUs to display config under
'events' directory. The specific PMU support itself will come
in next patches, however this is how the sysfs group will look
like:
# ls /sys/devices/cpu/events/
branch-instructions
branch-misses
bus-cycles
cache-misses
cache-references
cpu-cycles
instructions
ref-cycles
stalled-cycles-backend
stalled-cycles-frontend
The file - hw event ID mapping is:
file hw event ID
---------------------------------------------------------------
cpu-cycles PERF_COUNT_HW_CPU_CYCLES
instructions PERF_COUNT_HW_INSTRUCTIONS
cache-references PERF_COUNT_HW_CACHE_REFERENCES
cache-misses PERF_COUNT_HW_CACHE_MISSES
branch-instructions PERF_COUNT_HW_BRANCH_INSTRUCTIONS
branch-misses PERF_COUNT_HW_BRANCH_MISSES
bus-cycles PERF_COUNT_HW_BUS_CYCLES
stalled-cycles-frontend PERF_COUNT_HW_STALLED_CYCLES_FRONTEND
stalled-cycles-backend PERF_COUNT_HW_STALLED_CYCLES_BACKEND
ref-cycles PERF_COUNT_HW_REF_CPU_CYCLES
Each file in the 'events' directory contains the term translation
for the symbolic hw event for the currently running cpu model.
# cat /sys/devices/cpu/events/stalled-cycles-backend
event=0xb1,umask=0x01,inv,cmask=0x01
Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1349873598-12583-2-git-send-email-jolsa@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The following patch adds perf_event support for the Xeon-Phi
PMU, as documented in the "Intel Xeon Phi Coprocessor (codename:
Knights Corner) Performance Monitoring Units" manual.
Even though it is a co-processor, a Phi runs a full Linux
environment and can support performance counters.
This is just barebones support, it does not add support for
interesting new features such as the SPFLT intruction that
allows starting/stopping events without entering the kernel.
The PMU internally is just like that of an original Pentium, but
a "P6-like" MSR interface is provided. The interface is
different enough from a real P6 that it's not easy (or
practical) to re-use the code in perf_event_p6.c
Acked-by: Lawrence F Meadows <lawrence.f.meadows@intel.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: eranian@gmail.com
Cc: Lawrence F <lawrence.f.meadows@intel.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1209261405320.8398@vincent-weaver-1.um.maine.edu
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch updates the existing Intel IvyBridge (model 58)
support with proper PEBS event constraints. It cannot reuse
the same as SandyBridge because some events (0xd3) are
specific to IvyBridge.
Also there is no UOPS_DISPATCHED.THREAD on IVB, so do not
populate the PERF_COUNT_HW_STALLED_CYCLES_BACKEND mapping.
Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: ak@linux.intel.com
Link: http://lkml.kernel.org/r/20120910230701.GA5898@quad
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Some PMUs don't provide a full register set for their sample,
specifically 'advanced' PMUs like AMD IBS and Intel PEBS which provide
'better' than regular interrupt accuracy.
In this case we use the interrupt regs as basis and over-write some
fields (typically IP) with different information.
The perf core however uses user_mode() to distinguish user/kernel
samples, user_mode() relies on regs->cs. If the interrupt skid pushed
us over a boundary the new IP might not be in the same domain as the
interrupt.
Commit ce5c1fe9a9 ("perf/x86: Fix USER/KERNEL tagging of samples")
tried to fix this by making the perf core use kernel_ip(). This
however is wrong (TM), as pointed out by Linus, since it doesn't allow
for VM86 and non-zero based segments in IA32 mode.
Therefore, provide a new helper to set the regs->ip field,
set_linear_ip(), which massages the regs into a suitable state
assuming the provided IP is in fact a linear address.
Also modify perf_instruction_pointer() and perf_callchain_user() to
deal with segments base offsets.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1341910954.3462.102.camel@twins
Signed-off-by: Ingo Molnar <mingo@kernel.org>
All these are basically boolean flags, use a bitfield to save a few
bytes.
Suggested-by: Borislav Petkov <bp@amd64.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-vsevd5g8lhcn129n3s7trl7r@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Recent Intel microcode resolved the SNB-PEBS issues, so conditionally
enable PEBS on SNB hardware depending on the microcode revision.
Thanks to Stephane for figuring out the various microcode revisions.
Suggested-by: Stephane Eranian <eranian@google.com>
Acked-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-v3672ziwh9damwqwh1uz3krm@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
On Sandy Bridge in non HT mode there are 8 counters available.
Since every counter can write a PEBS record assuming there are
4 max is incorrect. Use the reported counter number -- with an
upper limit for a static array -- instead.
Also I made the warning messages a bit more informational.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1338944211-28275-2-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Move the wrmslr() debug wrapper to the common header now that all the
include games are gone. Also clean it up a bit to avoid multiple
evaluation of the argument.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-l4gkfnivwv4yi5mqxjlovymx@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now that there's finally a chip with working PEBS (IvyBridge), we can
enable the hardware and implement cycles:p for SNB/IVB.
Cc: Stephane Eranian <eranian@google.com>
Requested-and-tested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1338884803.28282.153.camel@twins
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Zheng Yan reported that event group validation can wreck event state
when Intel extra_reg allocation changes event state.
Validation shouldn't change any persistent state. Cloning events in
validate_{event,group}() isn't really pretty either, so add a few
special cases to avoid modifying the event state.
The code is restructured to minimize the special case impact.
Reported-by: Zheng Yan <zheng.z.yan@linux.intel.com>
Acked-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1338903031.28282.175.camel@twins
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Adding sysfs group 'format' attribute for pmu device that
contains a syntax description on how to construct raw events.
The event configuration is described in following
struct pefr_event_attr attributes:
config
config1
config2
Each sysfs attribute within the format attribute group,
describes mapping of name and bitfield definition within
one of above attributes.
eg:
"/sys/...<dev>/format/event" contains "config:0-7"
"/sys/...<dev>/format/umask" contains "config:8-15"
"/sys/...<dev>/format/usr" contains "config:16"
the attribute value syntax is:
line: config ':' bits
config: 'config' | 'config1' | 'config2"
bits: bits ',' bit_term | bit_term
bit_term: VALUE '-' VALUE | VALUE
Adding format attribute definitions for x86 cpu pmus.
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-vhdk5y2hyype9j63prymty36@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
