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  1. 10 11月, 2020 2 次提交
  3. 10 9月, 2020 1 次提交
    • K
      perf/x86/intel/ds: Fix x86_pmu_stop warning for large PEBS · 35d1ce6b
      由 Kan Liang 提交于 
      A warning as below may be triggered when sampling with large PEBS.

[  410.411250] perf: interrupt took too long (72145 > 71975), lowering
kernel.perf_event_max_sample_rate to 2000
[  410.724923] ------------[ cut here ]------------
[  410.729822] WARNING: CPU: 0 PID: 16397 at arch/x86/events/core.c:1422
x86_pmu_stop+0x95/0xa0
[  410.933811]  x86_pmu_del+0x50/0x150
[  410.937304]  event_sched_out.isra.0+0xbc/0x210
[  410.941751]  group_sched_out.part.0+0x53/0xd0
[  410.946111]  ctx_sched_out+0x193/0x270
[  410.949862]  __perf_event_task_sched_out+0x32c/0x890
[  410.954827]  ? set_next_entity+0x98/0x2d0
[  410.958841]  __schedule+0x592/0x9c0
[  410.962332]  schedule+0x5f/0xd0
[  410.965477]  exit_to_usermode_loop+0x73/0x120
[  410.969837]  prepare_exit_to_usermode+0xcd/0xf0
[  410.974369]  ret_from_intr+0x2a/0x3a
[  410.977946] RIP: 0033:0x40123c
[  411.079661] ---[ end trace bc83adaea7bb664a ]---

In the non-overflow context, e.g., context switch, with large PEBS, perf
may stop an event twice. An example is below.

  //max_samples_per_tick is adjusted to 2
  //NMI is triggered
  intel_pmu_handle_irq()
     handle_pmi_common()
       drain_pebs()
         __intel_pmu_pebs_event()
           perf_event_overflow()
             __perf_event_account_interrupt()
               hwc->interrupts = 1
               return 0
  //A context switch happens right after the NMI.
  //In the same tick, the perf_throttled_seq is not changed.
  perf_event_task_sched_out()
     perf_pmu_sched_task()
       intel_pmu_drain_pebs_buffer()
         __intel_pmu_pebs_event()
           perf_event_overflow()
             __perf_event_account_interrupt()
               ++hwc->interrupts >= max_samples_per_tick
               return 1
           x86_pmu_stop();  # First stop
     perf_event_context_sched_out()
       task_ctx_sched_out()
         ctx_sched_out()
           event_sched_out()
             x86_pmu_del()
               x86_pmu_stop();  # Second stop and trigger the warning

Perf should only invoke the perf_event_overflow() in the overflow
context.

Current drain_pebs() is called from:
- handle_pmi_common()			-- overflow context
- intel_pmu_pebs_sched_task()		-- non-overflow context
- intel_pmu_pebs_disable()		-- non-overflow context
- intel_pmu_auto_reload_read()		-- possible overflow context
  With PERF_SAMPLE_READ + PERF_FORMAT_GROUP, the function may be
  invoked in the NMI handler. But, before calling the function, the
  PEBS buffer has already been drained. The __intel_pmu_pebs_event()
  will not be called in the possible overflow context.

To fix the issue, an indicator is required to distinguish between the
overflow context aka handle_pmi_common() and other cases.
The dummy regs pointer can be used as the indicator.

In the non-overflow context, perf should treat the last record the same
as other PEBS records, and doesn't invoke the generic overflow handler.

Fixes: 21509084 ("perf/x86/intel: Handle multiple records in the PEBS buffer")
Reported-by: NLike Xu <like.xu@linux.intel.com>
Suggested-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: NLike Xu <like.xu@linux.intel.com>
Link: https://lkml.kernel.org/r/20200902210649.2743-1-kan.liang@linux.intel.com
      35d1ce6b
  5. 08 7月, 2020 1 次提交
  7. 11 2月, 2020 1 次提交
    • K
      perf/x86/intel: Fix inaccurate period in context switch for auto-reload · f861854e
      由 Kan Liang 提交于 
      Perf doesn't take the left period into account when auto-reload is
enabled with fixed period sampling mode in context switch.

Here is the MSR trace of the perf command as below.
(The MSR trace is simplified from a ftrace log.)

    #perf record -e cycles:p -c 2000000 -- ./triad_loop

      //The MSR trace of task schedule out
      //perf disable all counters, disable PEBS, disable GP counter 0,
      //read GP counter 0, and re-enable all counters.
      //The counter 0 stops at 0xfffffff82840
      write_msr: MSR_CORE_PERF_GLOBAL_CTRL(38f), value 0
      write_msr: MSR_IA32_PEBS_ENABLE(3f1), value 0
      write_msr: MSR_P6_EVNTSEL0(186), value 40003003c
      rdpmc: 0, value fffffff82840
      write_msr: MSR_CORE_PERF_GLOBAL_CTRL(38f), value f000000ff

      //The MSR trace of the same task schedule in again
      //perf disable all counters, enable and set GP counter 0,
      //enable PEBS, and re-enable all counters.
      //0xffffffe17b80 (-2000000) is written to GP counter 0.
      write_msr: MSR_CORE_PERF_GLOBAL_CTRL(38f), value 0
      write_msr: MSR_IA32_PMC0(4c1), value ffffffe17b80
      write_msr: MSR_P6_EVNTSEL0(186), value 40043003c
      write_msr: MSR_IA32_PEBS_ENABLE(3f1), value 1
      write_msr: MSR_CORE_PERF_GLOBAL_CTRL(38f), value f000000ff

When the same task schedule in again, the counter should starts from
previous left. However, it starts from the fixed period -2000000 again.

A special variant of intel_pmu_save_and_restart() is used for
auto-reload, which doesn't update the hwc->period_left.
When the monitored task schedules in again, perf doesn't know the left
period. The fixed period is used, which is inaccurate.

With auto-reload, the counter always has a negative counter value. So
the left period is -value. Update the period_left in
intel_pmu_save_and_restart_reload().

With the patch:

      //The MSR trace of task schedule out
      write_msr: MSR_CORE_PERF_GLOBAL_CTRL(38f), value 0
      write_msr: MSR_IA32_PEBS_ENABLE(3f1), value 0
      write_msr: MSR_P6_EVNTSEL0(186), value 40003003c
      rdpmc: 0, value ffffffe25cbc
      write_msr: MSR_CORE_PERF_GLOBAL_CTRL(38f), value f000000ff

      //The MSR trace of the same task schedule in again
      write_msr: MSR_CORE_PERF_GLOBAL_CTRL(38f), value 0
      write_msr: MSR_IA32_PMC0(4c1), value ffffffe25cbc
      write_msr: MSR_P6_EVNTSEL0(186), value 40043003c
      write_msr: MSR_IA32_PEBS_ENABLE(3f1), value 1
      write_msr: MSR_CORE_PERF_GLOBAL_CTRL(38f), value f000000ff

Fixes: d31fc13f ("perf/x86/intel: Fix event update for auto-reload")
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200121190125.3389-1-kan.liang@linux.intel.com
      f861854e
  9. 10 12月, 2019 1 次提交
  11. 28 8月, 2019 1 次提交
  13. 25 7月, 2019 1 次提交
  15. 25 6月, 2019 3 次提交
  17. 21 5月, 2019 1 次提交
    • S
      perf/x86/intel/ds: Fix EVENT vs. UEVENT PEBS constraints · 23e3983a
      由 Stephane Eranian 提交于 
      This patch fixes an bug revealed by the following commit:

  6b89d4c1 ("perf/x86/intel: Fix INTEL_FLAGS_EVENT_CONSTRAINT* masking")

That patch modified INTEL_FLAGS_EVENT_CONSTRAINT() to only look at the event code
when matching a constraint. If code+umask were needed, then the
INTEL_FLAGS_UEVENT_CONSTRAINT() macro was needed instead.
This broke with some of the constraints for PEBS events.

Several of them, including the one used for cycles:p, cycles:pp, cycles:ppp
fell in that category and caused the event to be rejected in PEBS mode.
In other words, on some platforms a cmdline such as:

  $ perf top -e cycles:pp

would fail with -EINVAL.

This patch fixes this bug by properly using INTEL_FLAGS_UEVENT_CONSTRAINT()
when needed in the PEBS constraint tables.
Reported-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NStephane Eranian <eranian@google.com>
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: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: kan.liang@intel.com
Link: http://lkml.kernel.org/r/20190521005246.423-1-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      23e3983a
  19. 29 4月, 2019 1 次提交
    • I
      x86/paravirt: Standardize 'insn_buff' variable names · 1fc654cf
      由 Ingo Molnar 提交于 
      We currently have 6 (!) separate naming variants to name temporary instruction
buffers that are used for code patching:

 - insnbuf
 - insnbuff
 - insn_buff
 - insn_buffer
 - ibuf
 - ibuffer

These are used as local variables, percpu fields and function parameters.

Standardize all the names to a single variant: 'insn_buff'.

Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      1fc654cf
  21. 16 4月, 2019 6 次提交
    • K
      perf/x86/intel: Add Icelake support · 60176089
      由 Kan Liang 提交于 
      Add Icelake core PMU perf code, including constraint tables and the main
enable code.

Icelake expanded the generic counters to always 8 even with HT on, but a
range of events cannot be scheduled on the extra 4 counters.
Add new constraint ranges to describe this to the scheduler.
The number of constraints that need to be checked is larger now than
with earlier CPUs.
At some point we may need a new data structure to look them up more
efficiently than with linear search. So far it still seems to be
acceptable however.

Icelake added a new fixed counter SLOTS. Full support for it is added
later in the patch series.

The cache events table is identical to Skylake.

Compare to PEBS instruction event on generic counter, fixed counter 0
has less skid. Force instruction:ppp always in fixed counter 0.
Originally-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
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: acme@kernel.org
Cc: jolsa@kernel.org
Link: https://lkml.kernel.org/r/20190402194509.2832-9-kan.liang@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      60176089
    • P
      perf/x86: Support constraint ranges · 63b79f6e
      由 Peter Zijlstra 提交于 
      Icelake extended the general counters to 8, even when SMT is enabled.
However only a (large) subset of the events can be used on all 8
counters.

The events that can or cannot be used on all counters are organized
in ranges.

A lot of scheduler constraints are required to handle all this.

To avoid blowing up the tables add event code ranges to the constraint
tables, and a new inline function to match them.
Originally-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> # developer hat on
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> # maintainer hat on
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: acme@kernel.org
Cc: jolsa@kernel.org
Link: https://lkml.kernel.org/r/20190402194509.2832-8-kan.liang@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      63b79f6e
    • K
      perf/x86/intel: Support adaptive PEBS v4 · c22497f5
      由 Kan Liang 提交于 
      Adaptive PEBS is a new way to report PEBS sampling information. Instead
of a fixed size record for all PEBS events it allows to configure the
PEBS record to only include the information needed. Events can then opt
in to use such an extended record, or stay with a basic record which
only contains the IP.

The major new feature is to support LBRs in PEBS record.
Besides normal LBR, this allows (much faster) large PEBS, while still
supporting callstacks through callstack LBR. So essentially a lot of
profiling can now be done without frequent interrupts, dropping the
overhead significantly.

The main requirement still is to use a period, and not use frequency
mode, because frequency mode requires reevaluating the frequency on each
overflow.

The floating point state (XMM) is also supported, which allows efficient
profiling of FP function arguments.

Introduce specific drain function to handle variable length records.
Use a new callback to parse the new record format, and also handle the
STATUS field now being at a different offset.

Add code to set up the configuration register. Since there is only a
single register, all events either get the full super set of all events,
or only the basic record.
Originally-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
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: acme@kernel.org
Cc: jolsa@kernel.org
Link: https://lkml.kernel.org/r/20190402194509.2832-6-kan.liang@linux.intel.com
[ Renamed GPRS => GP. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      c22497f5
    • K
      perf/x86/intel/ds: Extract code of event update in short period · 477f00f9
      由 Kan Liang 提交于 
      The drain_pebs() could be called twice in a short period for auto-reload
event in pmu::read(). The intel_pmu_save_and_restart_reload() should be
called to update the event->count.

This case should also be handled on Icelake. Extract the code for
later reuse.
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
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: acme@kernel.org
Cc: jolsa@kernel.org
Link: https://lkml.kernel.org/r/20190402194509.2832-5-kan.liang@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      477f00f9
    • A
      perf/x86/intel: Extract memory code PEBS parser for reuse · 48f38aa4
      由 Andi Kleen 提交于 
      Extract some code related to memory profiling from the PEBS record
parser into separate functions. It can be reused by the upcoming
adaptive PEBS parser. No functional changes.
Rename intel_hsw_weight to intel_get_tsx_weight, and
intel_hsw_transaction to intel_get_tsx_transaction. Because the input is
not the hsw pebs format anymore.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
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: acme@kernel.org
Cc: jolsa@kernel.org
Link: https://lkml.kernel.org/r/20190402194509.2832-4-kan.liang@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      48f38aa4
    • K
      perf/x86: Support outputting XMM registers · 878068ea
      由 Kan Liang 提交于 
      Starting from Icelake, XMM registers can be collected in PEBS record.
But current code only output the pt_regs.

Add a new struct x86_perf_regs for both pt_regs and xmm_regs. The
xmm_regs will be used later to keep a pointer to PEBS record which has
XMM information.

XMM registers are 128 bit. To simplify the code, they are handled like
two different registers, which means setting two bits in the register
bitmap. This also allows only sampling the lower 64bit bits in XMM.

The index of XMM registers starts from 32. There are 16 XMM registers.
So all reserved space for regs are used. Remove REG_RESERVED.

Add PERF_REG_X86_XMM_MAX, which stands for the max number of all x86
regs including both GPRs and XMM.

Add REG_NOSUPPORT for 32bit to exclude unsupported registers.

Previous platforms can not collect XMM information in PEBS record.
Adding pebs_no_xmm_regs to indicate the unsupported platforms.

The common code still validates the supported registers. However, it
cannot check model specific registers, e.g. XMM. Add extra check in
x86_pmu_hw_config() to reject invalid config of regs_user and regs_intr.
The regs_user never supports XMM collection.
The regs_intr only supports XMM collection when sampling PEBS event on
icelake and later platforms.
Originally-by: NAndi Kleen <ak@linux.intel.com>
Suggested-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
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: acme@kernel.org
Cc: jolsa@kernel.org
Link: https://lkml.kernel.org/r/20190402194509.2832-3-kan.liang@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      878068ea
  23. 11 2月, 2019 1 次提交
    • A
      perf/x86/kvm: Avoid unnecessary work in guest filtering · 9b545c04
      由 Andi Kleen 提交于 
      KVM added a workaround for PEBS events leaking into guests with
commit:

  26a4f3c0 ("perf/x86: disable PEBS on a guest entry.")

This uses the VT entry/exit list to add an extra disable of the
PEBS_ENABLE MSR.

Intel also added a fix for this issue to microcode updates on
Haswell/Broadwell/Skylake.

It turns out using the MSR entry/exit list makes VM exits
significantly slower. The list is only needed for disabling
PEBS, because the GLOBAL_CTRL change gets optimized by
KVM into changing the VMCS.

Check for the microcode updates that have the microcode
fix for leaking PEBS, and disable the extra entry/exit list
entry for PEBS_ENABLE. In addition we always clear the
GLOBAL_CTRL for the PEBS counter while running in the guest,
which is enough to make them never fire at the wrong
side of the host/guest transition.

The overhead for VM exits with the filtering active with the patch is
reduced from 8% to 4%.

The microcode patch has already been merged into future platforms.
This patch is one-off thing. The quirks is used here.

For other old platforms which doesn't have microcode patch and quirks,
extra disable of the PEBS_ENABLE MSR is still required.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
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 Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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: bp@alien8.de
Link: https://lkml.kernel.org/r/1549319013-4522-2-git-send-email-kan.liang@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      9b545c04
  25. 03 12月, 2018 1 次提交
    • I
      x86: Fix various typos in comments · a97673a1
      由 Ingo Molnar 提交于 
      Go over arch/x86/ and fix common typos in comments,
and a typo in an actual function argument name.

No change in functionality intended.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      a97673a1
  27. 25 7月, 2018 4 次提交
  29. 15 7月, 2018 1 次提交
    • H
      x86/events/intel/ds: Fix bts_interrupt_threshold alignment · 2c991e40
      由 Hugh Dickins 提交于 
      Markus reported that BTS is sporadically missing the tail of the trace
in the perf_event data buffer: [decode error (1): instruction overflow]
shown in GDB; and bisected it to the conversion of debug_store to PTI.

A little "optimization" crept into alloc_bts_buffer(), which mistakenly
placed bts_interrupt_threshold away from the 24-byte record boundary.
Intel SDM Vol 3B 17.4.9 says "This address must point to an offset from
the BTS buffer base that is a multiple of the BTS record size."

Revert "max" from a byte count to a record count, to calculate the
bts_interrupt_threshold correctly: which turns out to fix problem seen.

Fixes: c1961a46 ("x86/events/intel/ds: Map debug buffers in cpu_entry_area")
Reported-and-tested-by: NMarkus T Metzger <markus.t.metzger@intel.com>
Signed-off-by: NHugh Dickins <hughd@google.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@intel.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: stable@vger.kernel.org # v4.14+
Link: https://lkml.kernel.org/r/alpine.LSU.2.11.1807141248290.1614@eggly.anvils
      2c991e40
  31. 05 4月, 2018 1 次提交
    • S
      perf/x86/intel: Move regs->flags EXACT bit init · d1e7e602
      由 Stephane Eranian 提交于 
      This patch removes a redundant store on regs->flags introduced
by commit:

  71eb9ee9 ("perf/x86/intel: Fix linear IP of PEBS real_ip on Haswell and later CPUs")

We were clearing the PERF_EFLAGS_EXACT but it was overwritten by
regs->flags = pebs->flags later on.

The PERF_EFLAGS_EXACT is a software flag using bit 3 of regs->flags.
X86 marks this bit as Reserved. To make sure this bit is zero before
we do any IP processing, we clear it explicitly.

Patch also removes the following assignment:

	regs->flags = pebs->flags | (regs->flags & PERF_EFLAGS_VM);

Because there is no regs->flags to preserve anymore because
set_linear_ip() is not called until later.
Signed-off-by: NStephane Eranian <eranian@google.com>
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: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: kan.liang@intel.com
Link: http://lkml.kernel.org/r/1522909791-32498-1-git-send-email-eranian@google.com
[ Improve capitalization, punctuation and clarity of comments. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      d1e7e602
  33. 27 3月, 2018 1 次提交
    • S
      perf/x86/intel: Fix linear IP of PEBS real_ip on Haswell and later CPUs · 71eb9ee9
      由 Stephane Eranian 提交于 
      this patch fix a bug in how the pebs->real_ip is handled in the PEBS
handler. real_ip only exists in Haswell and later processor. It is
actually the eventing IP, i.e., where the event occurred. As opposed
to the pebs->ip which is the PEBS interrupt IP which is always off
by one.

The problem is that the real_ip just like the IP needs to be fixed up
because PEBS does not record all the machine state registers, and
in particular the code segement (cs). This is why we have the set_linear_ip()
function. The problem was that set_linear_ip() was only used on the pebs->ip
and not the pebs->real_ip.

We have profiles which ran into invalid callstacks because of this.
Here is an example:

 .....  0: ffffffffffffff80 recent entry, marker kernel v
 .....  1: 000000000040044d <= user address in kernel space!
 .....  2: fffffffffffffe00 marker enter user v
 .....  3: 000000000040044d
 .....  4: 00000000004004b6 oldest entry

Debugging output in get_perf_callchain():

 [  857.769909] CALLCHAIN: CPU8 ip=40044d regs->cs=10 user_mode(regs)=0

The problem is that the kernel entry in 1: points to a user level
address. How can that be?

The reason is that with PEBS sampling the instruction that caused the event
to occur and the instruction where the CPU was when the interrupt was posted
may be far apart. And sometime during that time window, the privilege level may
change. This happens, for instance, when the PEBS sample is taken close to a
kernel entry point. Here PEBS, eventing IP (real_ip) captured a user level
instruction. But by the time the PMU interrupt fired, the processor had already
entered kernel space. This is why the debug output shows a user address with
user_mode() false.

The problem comes from PEBS not recording the code segment (cs) register.
The register is used in x86_64 to determine if executing in kernel vs user
space. This is okay because the kernel has a software workaround called
set_linear_ip(). But the issue in setup_pebs_sample_data() is that
set_linear_ip() is never called on the real_ip value when it is available
(Haswell and later) and precise_ip > 1.

This patch fixes this problem and eliminates the callchain discrepancy.

The patch restructures the code around set_linear_ip() to minimize the number
of times the IP has to be set.
Signed-off-by: NStephane Eranian <eranian@google.com>
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: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: kan.liang@intel.com
Link: http://lkml.kernel.org/r/1521788507-10231-1-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      71eb9ee9
  35. 20 3月, 2018 1 次提交
  37. 09 3月, 2018 2 次提交
    • K
      perf/x86/intel/ds: Introduce ->read() function for auto-reload events and... · 5bee2cc6
      由 Kan Liang 提交于 
      perf/x86/intel/ds: Introduce ->read() function for auto-reload events and flush the PEBS buffer there

There is no way to get exact auto-reload times and values which are needed
for event updates unless we flush the PEBS buffer.

Introduce intel_pmu_auto_reload_read() to drain the PEBS buffer for
auto reload event. To prevent races with the hardware, we can only
call drain_pebs() when the PMU is disabled.
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
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: acme@kernel.org
Link: http://lkml.kernel.org/r/1518474035-21006-4-git-send-email-kan.liang@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      5bee2cc6
    • K
      perf/x86/intel: Fix event update for auto-reload · d31fc13f
      由 Kan Liang 提交于 
      There is a bug when reading event->count with large PEBS enabled.

Here is an example:

  # ./read_count
  0x71f0
  0x122c0
  0x1000000001c54
  0x100000001257d
  0x200000000bdc5

In fixed period mode, the auto-reload mechanism could be enabled for
PEBS events, but the calculation of event->count does not take the
auto-reload values into account.

Anyone who reads event->count will get the wrong result, e.g x86_pmu_read().

This bug was introduced with the auto-reload mechanism enabled since
commit:

  851559e3 ("perf/x86/intel: Use the PEBS auto reload mechanism when possible")

Introduce intel_pmu_save_and_restart_reload() to calculate the
event->count only for auto-reload.

Since the counter increments a negative counter value and overflows on
the sign switch, giving the interval:

        [-period, 0]

the difference between two consequtive reads is:

 A) value2 - value1;
    when no overflows have happened in between,
 B) (0 - value1) + (value2 - (-period));
    when one overflow happened in between,
 C) (0 - value1) + (n - 1) * (period) + (value2 - (-period));
    when @n overflows happened in between.

Here A) is the obvious difference, B) is the extension to the discrete
interval, where the first term is to the top of the interval and the
second term is from the bottom of the next interval and C) the extension
to multiple intervals, where the middle term is the whole intervals
covered.

The equation for all cases is:

    value2 - value1 + n * period

Previously the event->count is updated right before the sample output.
But for case A, there is no PEBS record ready. It needs to be specially
handled.

Remove the auto-reload code from x86_perf_event_set_period() since
we'll not longer call that function in this case.

Based-on-code-from: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
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: acme@kernel.org
Fixes: 851559e3 ("perf/x86/intel: Use the PEBS auto reload mechanism when possible")
Link: http://lkml.kernel.org/r/1518474035-21006-2-git-send-email-kan.liang@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      d31fc13f
  39. 25 1月, 2018 1 次提交
    • P
      perf/x86: Fix perf,x86,cpuhp deadlock · efe951d3
      由 Peter Zijlstra 提交于 
      More lockdep gifts, a 5-way lockup race:

	perf_event_create_kernel_counter()
	  perf_event_alloc()
	    perf_try_init_event()
	      x86_pmu_event_init()
		__x86_pmu_event_init()
		  x86_reserve_hardware()
 #0		    mutex_lock(&pmc_reserve_mutex);
		    reserve_ds_buffer()
 #1		      get_online_cpus()

	perf_event_release_kernel()
	  _free_event()
	    hw_perf_event_destroy()
	      x86_release_hardware()
 #0		mutex_lock(&pmc_reserve_mutex)
		release_ds_buffer()
 #1		  get_online_cpus()

 #1	do_cpu_up()
	  perf_event_init_cpu()
 #2	    mutex_lock(&pmus_lock)
 #3	    mutex_lock(&ctx->mutex)

	sys_perf_event_open()
	  mutex_lock_double()
 #3	    mutex_lock(ctx->mutex)
 #4	    mutex_lock_nested(ctx->mutex, 1);

	perf_try_init_event()
 #4	  mutex_lock_nested(ctx->mutex, 1)
	  x86_pmu_event_init()
	    intel_pmu_hw_config()
	      x86_add_exclusive()
 #0		mutex_lock(&pmc_reserve_mutex)

Fix it by using ordering constructs instead of locking.
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>
      efe951d3
  41. 05 1月, 2018 1 次提交
  43. 24 12月, 2017 2 次提交
    • H
      x86/events/intel/ds: Map debug buffers in cpu_entry_area · c1961a46
      由 Hugh Dickins 提交于 
      The BTS and PEBS buffers both have their virtual addresses programmed into
the hardware.  This means that any access to them is performed via the page
tables.  The times that the hardware accesses these are entirely dependent
on how the performance monitoring hardware events are set up.  In other
words, there is no way for the kernel to tell when the hardware might
access these buffers.

To avoid perf crashes, place 'debug_store' allocate pages and map them into
the cpu_entry_area.

The PEBS fixup buffer does not need this treatment.

[ tglx: Got rid of the kaiser_add_mapping() complication ]
Signed-off-by: NHugh Dickins <hughd@google.com>
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: keescook@google.com
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      c1961a46
    • T
      x86/cpu_entry_area: Add debugstore entries to cpu_entry_area · 10043e02
      由 Thomas Gleixner 提交于 
      The Intel PEBS/BTS debug store is a design trainwreck as it expects virtual
addresses which must be visible in any execution context.

So it is required to make these mappings visible to user space when kernel
page table isolation is active.

Provide enough room for the buffer mappings in the cpu_entry_area so the
buffers are available in the user space visible page tables.

At the point where the kernel side entry area is populated there is no
buffer available yet, but the kernel PMD must be populated. To achieve this
set the entries for these buffers to non present.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      10043e02
  45. 02 11月, 2017 1 次提交
    • G
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      由 Greg Kroah-Hartman 提交于 
      Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: NKate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
  47. 29 8月, 2017 1 次提交
    • K
      perf/core, x86: Add PERF_SAMPLE_PHYS_ADDR · fc7ce9c7
      由 Kan Liang 提交于 
      For understanding how the workload maps to memory channels and hardware
behavior, it's very important to collect address maps with physical
addresses. For example, 3D XPoint access can only be found by filtering
the physical address.

Add a new sample type for physical address.

perf already has a facility to collect data virtual address. This patch
introduces a function to convert the virtual address to physical address.
The function is quite generic and can be extended to any architecture as
long as a virtual address is provided.

 - For kernel direct mapping addresses, virt_to_phys is used to convert
   the virtual addresses to physical address.

 - For user virtual addresses, __get_user_pages_fast is used to walk the
   pages tables for user physical address.

 - This does not work for vmalloc addresses right now. These are not
   resolved, but code to do that could be added.

The new sample type requires collecting the virtual address. The
virtual address will not be output unless SAMPLE_ADDR is applied.

For security, the physical address can only be exposed to root or
privileged user.
Tested-by: NMadhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: NKan Liang <kan.liang@intel.com>
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: acme@kernel.org
Cc: mpe@ellerman.id.au
Link: http://lkml.kernel.org/r/1503967969-48278-1-git-send-email-kan.liang@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      fc7ce9c7
  49. 25 8月, 2017 2 次提交
    • A
      perf/x86: Fix data source decoding for Skylake · 6ae5fa61
      由 Andi Kleen 提交于 
      Skylake changed the encoding of the PEBS data source field.
Some combinations are not available anymore, but some new cases
e.g. for L4 cache hit are added.

Fix up the conversion table for Skylake, similar as had been done
for Nehalem.

On Skylake server the encoding for L4 actually means persistent
memory. Handle this case too.

To properly describe it in the abstracted perf format I had to add
some new fields. Since a hit can have only one level add a new
field that is an enumeration, not a bit field to describe
the level. It can describe any level. Some numbers are also
used to describe PMEM and LFB.

Also add a new generic remote flag that can be combined with
the generic level to signify a remote cache.

And there is an extension field for the snoop indication to handle
the Forward state.

I didn't add a generic flag for hops because it's not needed
for Skylake.

I changed the existing encodings for older CPUs to also fill in the
new level and remote fields.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: jolsa@kernel.org
Link: http://lkml.kernel.org/r/20170816222156.19953-3-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      6ae5fa61
    • A
      perf/x86: Move Nehalem PEBS code to flag · 95298355
      由 Andi Kleen 提交于 
      Minor cleanup: use an explicit x86_pmu flag to handle the
missing Lock / TLB information on Nehalem, instead of always
checking the model number for each PEBS sample.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: jolsa@kernel.org
Link: http://lkml.kernel.org/r/20170816222156.19953-2-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      95298355
  51. 21 7月, 2017 1 次提交
    • J
      perf/x86/intel: Add proper condition to run sched_task callbacks · df6c3db8
      由 Jiri Olsa 提交于 
      We have 2 functions using the same sched_task callback:

  - PEBS drain for free running counters
  - LBR save/store

Both of them are called from intel_pmu_sched_task() and
either of them can be unwillingly triggered when the
other one is configured to run.

Let's say there's PEBS drain configured in sched_task
callback for the event, but in the callback itself
(intel_pmu_sched_task()) we will also run the code for
LBR save/restore, which we did not ask for, but the
code in intel_pmu_sched_task() does not check for that.

This can lead to extra cycles in some perf monitoring,
like when we monitor PEBS event without LBR data.

  # perf record --no-timestamp -c 10000 -e cycles:p ./perf bench sched pipe -l 1000000

  (We need PEBS, non freq/non timestamp event to enable
   the sched_task callback)

The perf stat of cycles and msr:write_msr for above
command before the change:
  ...
  Performance counter stats for './perf record --no-timestamp -c 10000 -e cycles:p \
                                 ./perf bench sched pipe -l 1000000' (5 runs):

    18,519,557,441      cycles:k
        91,195,527      msr:write_msr

      29.334476406 seconds time elapsed

And after the change:
  ...
  Performance counter stats for './perf record --no-timestamp -c 10000 -e cycles:p \
                                 ./perf bench sched pipe -l 1000000' (5 runs):

    18,704,973,540      cycles:k
        27,184,720      msr:write_msr

      16.977875900 seconds time elapsed

There's no affect on cycles:k because the sched_task happens
with events switched off, however the msr:write_msr tracepoint
counter together with almost 50% of time speedup show the
improvement.

Monitoring LBR event and having extra PEBS drain processing
in sched_task callback showed just a little speedup, because
the drain function does not do much extra work in case there
is no PEBS data.

Adding conditions to recognize the configured work that needs
to be done in the x86_pmu's sched_task callback.
Suggested-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20170719075247.GA27506@kravaSigned-off-by: NIngo Molnar <mingo@kernel.org>
      df6c3db8