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  1. 14 4月, 2017 1 次提交
  3. 16 10月, 2016 1 次提交
    • D
      perf/x86/intel: Remove an inconsistent NULL check · 5c38181c
      由 Dan Carpenter 提交于 
      Smatch complains that we don't check "event->ctx" consistently.  It's
never NULL so we can just remove the check.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Carrillo-Cisneros <davidcc@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: kernel-janitors@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      5c38181c
  5. 10 8月, 2016 4 次提交
    • P
      perf/x86/intel: Clean up LBR state tracking · 3e2c1a67
      由 Peter Zijlstra 提交于 
      The lbr_context logic confused me; it appears to me to try and do the
same thing the pmu::sched_task() callback does now, but limited to
per-task events.

So rip it out. Afaict this should also improve performance, because I
think the current code can end up doing lbr_reset() twice, once from
the pmu::add() and then again from pmu::sched_task(), and MSR writes
(all 3*16 of them) are expensive!!

While thinking through the cases that need the reset it occured to me
the first install of an event in an active context needs to reset the
LBR (who knows what crap is in there), but detecting this case is
somewhat hard.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      3e2c1a67
    • P
      perf/x86/intel: Remove redundant test from intel_pmu_lbr_add() · a5dcff62
      由 Peter Zijlstra 提交于 
      By the time we call pmu::add(), event->ctx must be set, and we
even already rely on this, so remove that test from
intel_pmu_lbr_add().
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      a5dcff62
    • P
      perf/x86/intel: Eliminate dead code in intel_pmu_lbr_del() · c3a61a2c
      由 Peter Zijlstra 提交于 
      Since pmu::del() is always called under perf_pmu_disable(), the block
conditional on cpuc->enabled is dead.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      c3a61a2c
    • P
      perf/x86: Ensure perf_sched_cb_{inc,dec}() is only called from pmu::{add,del}() · 68f7082f
      由 Peter Zijlstra 提交于 
      Currently perf_sched_cb_{inc,dec}() are called from
pmu::{start,stop}(), which has the problem that this can happen from
NMI context, this is making it hard to optimize perf_pmu_sched_task().

Furthermore, we really only need this accounting on pmu::{add,del}(),
so doing it from pmu::{start,stop}() is doing more work than we really
need.

Introduce x86_pmu::{add,del}() and wire up the LBR and PEBS.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      68f7082f
  7. 07 7月, 2016 1 次提交
    • P
      perf/x86/intel: Fix rdlbr_to() MSR reading typo · aefbc4d0
      由 Peter Zijlstra 提交于 
      It helps to actually read the right MSR..
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Fixes: d4cf1949 ("perf/x86/intel: Add {rd,wr}lbr_{to,from} wrappers")
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      aefbc4d0
  9. 27 6月, 2016 5 次提交
    • P
      perf/x86/intel: Add {rd,wr}lbr_{to,from} wrappers · d4cf1949
      由 Peter Zijlstra 提交于 
      The whole rdmsr()/wrmsr() for lbr_from got a little unweildy with the
sign extension quirk, provide a few simple wrappers to clean things up.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Carrillo-Cisneros <davidcc@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      d4cf1949
    • D
      perf/x86/intel: Add MSR_LAST_BRANCH_FROM_x quirk for ctx switch · 71adae99
      由 David Carrillo-Cisneros 提交于 
      Add quirk for context switch to save/restore the value of
MSR_LAST_BRANCH_FROM_x when LBR is enabled and there is potential for
kernel addresses to be in the lbr_from register.

To test this patch, use a perf tool and kernel with the patch
next in this series. That patch removes the work around that masked
the hw bug:

  $ ./lbr_perf record --call-graph lbr -e cycles:k sleep 1

where lbr_perf is the patched perf tool, that allows to specify :k
on lbr mode. The above command will trigger a #GPF :

 WARNING: CPU: 28 PID: 14096 at arch/x86/mm/extable.c:65 ex_handler_wrmsr_unsafe+0x70/0x80
 unchecked MSR access error: WRMSR to 0x681 (tried to write 0x1fffffff81010794)
 ...
 Call Trace:
  [<ffffffff8167af49>] dump_stack+0x4d/0x63
  [<ffffffff810b9b15>] __warn+0xe5/0x100
  [<ffffffff810b9be9>] warn_slowpath_fmt+0x49/0x50
  [<ffffffff810abb40>] ex_handler_wrmsr_unsafe+0x70/0x80
  [<ffffffff810abc42>] fixup_exception+0x42/0x50
  [<ffffffff81079d1a>] do_general_protection+0x8a/0x160
  [<ffffffff81684ec2>] general_protection+0x22/0x30
  [<ffffffff810101b9>] ? intel_pmu_lbr_sched_task+0xc9/0x380
  [<ffffffff81009d7c>] intel_pmu_sched_task+0x3c/0x60
  [<ffffffff81003a2b>] x86_pmu_sched_task+0x1b/0x20
  [<ffffffff81192a5b>] perf_pmu_sched_task+0x6b/0xb0
  [<ffffffff8119746d>] __perf_event_task_sched_in+0x7d/0x150
  [<ffffffff810dd9dc>] finish_task_switch+0x15c/0x200
  [<ffffffff8167f894>] __schedule+0x274/0x6cc
  [<ffffffff8167fdd9>] schedule+0x39/0x90
  [<ffffffff81675398>] exit_to_usermode_loop+0x39/0x89
  [<ffffffff810028ce>] prepare_exit_to_usermode+0x2e/0x30
  [<ffffffff81683c1b>] retint_user+0x8/0x10
Signed-off-by: NDavid Carrillo-Cisneros <davidcc@google.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NStephane Eranian <eranian@google.com>
Reviewed-by: NAndi Kleen <ak@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1466533874-52003-5-git-send-email-davidcc@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      71adae99
    • D
      perf/x86/intel: Fix trivial formatting and style bug · 3812bba8
      由 David Carrillo-Cisneros 提交于 
      Replace spaces by tabs in LBR_FROM_* constants to align with newly
defined constant. Use BIT_ULL.
Signed-off-by: NDavid Carrillo-Cisneros <davidcc@google.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NStephane Eranian <eranian@google.com>
Reviewed-by: NAndi Kleen <ak@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1466533874-52003-4-git-send-email-davidcc@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      3812bba8
    • D
      perf/x86/intel: Fix MSR_LAST_BRANCH_FROM_x bug when no TSX · 19fc9ddd
      由 David Carrillo-Cisneros 提交于 
      Intel's SDM states that bits 61:62 in MSR_LAST_BRANCH_FROM_x are the
TSX flags for formats with LBR_TSX flags (i.e. LBR_FORMAT_EIP_EFLAGS2).

However, when the CPU has TSX support deactivated, bits 61:62 actually
behave as follows:

  - For wrmsr(), bits 61:62 are considered part of the sign extension.
  - When capturing branches, the LBR hw will always clear bits 61:62.
    regardless of the sign extension.

Therefore, if:

  1) LBR has TSX format.
  2) CPU has no TSX support enabled.

... then any value passed to wrmsr() must be sign extended to 63 bits
and any value from rdmsr() must be converted to have a sign extension
of 61 bits, ignoring the values at TSX flags.

This bug was masked by the work-around to the Intel's CPU bug:
BJ94. "LBR May Contain Incorrect Information When Using FREEZE_LBRS_ON_PMI"
in Document Number: 324643-037US.

The aforementioned work-around uses hw flags to filter out all kernel
branches, limiting LBR callstack to user level execution only.

Since user addresses are not sign extended, they do not trigger the wrmsr()
bug in MSR_LAST_BRANCH_FROM_x when saved/restored at context switch.

To verify the hw bug:

  $ perf record -b -e cycles sleep 1
  $ rdmsr -p 0 0x680
  0x1fffffffb0b9b0cc
  $ wrmsr -p 0 0x680 0x1fffffffb0b9b0cc
  write(): Input/output error

The quirk for LBR_FROM_ MSRs is required before calls to wrmsrl() and
after rdmsrl().

This patch introduces it for wrmsrl()'s done for testing LBR support.

Future patch in series adds the quirk for context switch, that would
be required if LBR callstack is to be enabled for ring 0.
Signed-off-by: NDavid Carrillo-Cisneros <davidcc@google.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NStephane Eranian <eranian@google.com>
Reviewed-by: NAndi Kleen <ak@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1466533874-52003-3-git-send-email-davidcc@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      19fc9ddd
    • D
      perf/x86/intel: Print LBR support statement after validation · f09509b9
      由 David Carrillo-Cisneros 提交于 
      The following commit:

  338b522c ("perf/x86/intel: Protect LBR and extra_regs against KVM lying")

added an additional test to LBR support detection that is performed after
printing the LBR support statement to dmesg.

Move the LBR support output after the very last test, to make sure we
print the true status of LBR support.
Signed-off-by: NDavid Carrillo-Cisneros <davidcc@google.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NStephane Eranian <eranian@google.com>
Reviewed-by: NAndi Kleen <ak@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1466533874-52003-2-git-send-email-davidcc@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      f09509b9
  11. 28 4月, 2016 1 次提交
  13. 23 4月, 2016 2 次提交
  15. 17 2月, 2016 2 次提交
  17. 06 1月, 2016 2 次提交
  19. 23 11月, 2015 2 次提交
    • A
      perf/x86: Add option to disable reading branch flags/cycles · b16a5b52
      由 Andi Kleen 提交于 
      With LBRv5 reading the extra LBR flags like mispredict, TSX, cycles is
not free anymore, as it has moved to a separate MSR.

For callstack mode we don't need any of this information; so we can
avoid the unnecessary MSR read. Add flags to the perf interface where
perf record can request not collecting this information.

Add branch_sample_type flags for CYCLES and FLAGS. It's a bit unusual
for branch_sample_types to be negative (disable), not positive (enable),
but since the legacy ABI reported the flags we need some form of
explicit disabling to avoid breaking the ABI.

After we have the flags the x86 perf code can keep track if any users
need the flags. If noone needs it the information is not collected.

This cuts down the cost of LBR callstack on Skylake significantly.
Profiling a kernel build with LBR call stack the average run time of
the PMI handler drops by 43%.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: jolsa@kernel.org
Link: http://lkml.kernel.org/r/1445366797-30894-2-git-send-email-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      b16a5b52
    • A
      perf/x86: Fix LBR call stack save/restore · b28ae956
      由 Andi Kleen 提交于 
      This fixes a bug I added in the following commit:

  90405aa0 ("perf/x86/intel/lbr: Limit LBR accesses to TOS in callstack mode")

The bug could lead to lost LBR call stacks. When restoring the LBR state
we need to use the TOS of the previous context, not the current context.
To do that we need to save/restore the TOS.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: jolsa@kernel.org
Link: http://lkml.kernel.org/r/1445366797-30894-1-git-send-email-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      b28ae956
  21. 20 10月, 2015 1 次提交
  23. 18 9月, 2015 1 次提交
  25. 13 9月, 2015 1 次提交
  27. 04 8月, 2015 5 次提交
  29. 07 6月, 2015 2 次提交
  31. 02 4月, 2015 2 次提交
  33. 19 2月, 2015 7 次提交