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  1. 20 4月, 2021 10 次提交
  3. 06 3月, 2021 1 次提交
  5. 10 2月, 2021 1 次提交
  7. 01 2月, 2021 4 次提交
    • K
      perf/x86/intel: Support CPUID 10.ECX to disable fixed counters · 32451614
      由 Kan Liang 提交于 
      With Architectural Performance Monitoring Version 5, CPUID 10.ECX cpu
leaf indicates the fixed counter enumeration. This extends the previous
count to a bitmap which allows disabling even lower fixed counters.
It could be used by a Hypervisor.

The existing intel_ctrl variable is used to remember the bitmask of the
counters. All code that reads all counters is fixed to check this extra
bitmask.
Suggested-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
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>
Link: https://lkml.kernel.org/r/1611873611-156687-6-git-send-email-kan.liang@linux.intel.com
      32451614
    • K
      perf/x86/intel: Add perf core PMU support for Sapphire Rapids · 61b985e3
      由 Kan Liang 提交于 
      Add perf core PMU support for the Intel Sapphire Rapids server, which is
the successor of the Intel Ice Lake server. The enabling code is based
on Ice Lake, but there are several new features introduced.

The event encoding is changed and simplified, e.g., the event codes
which are below 0x90 are restricted to counters 0-3. The event codes
which above 0x90 are likely to have no restrictions. The event
constraints, extra_regs(), and hardware cache events table are changed
accordingly.

A new Precise Distribution (PDist) facility is introduced, which
further minimizes the skid when a precise event is programmed on the GP
counter 0. Enable the Precise Distribution (PDist) facility with :ppp
event. For this facility to work, the period must be initialized with a
value larger than 127. Add spr_limit_period() to apply the limit for
:ppp event.

Two new data source fields, data block & address block, are added in the
PEBS Memory Info Record for the load latency event. To enable the
feature,
- An auxiliary event has to be enabled together with the load latency
  event on Sapphire Rapids. A new flag PMU_FL_MEM_LOADS_AUX is
  introduced to indicate the case. A new event, mem-loads-aux, is
  exposed to sysfs for the user tool.
  Add a check in hw_config(). If the auxiliary event is not detected,
  return an unique error -ENODATA.
- The union perf_mem_data_src is extended to support the new fields.
- Ice Lake and earlier models do not support block information, but the
  fields may be set by HW on some machines. Add pebs_no_block to
  explicitly indicate the previous platforms which don't support the new
  block fields. Accessing the new block fields are ignored on those
  platforms.

A new store Latency facility is introduced, which leverages the PEBS
facility where it can provide additional information about sampled
stores. The additional information includes the data address, memory
auxiliary info (e.g. Data Source, STLB miss) and the latency of the
store access. To enable the facility, the new event (0x02cd) has to be
programed on the GP counter 0. A new flag PERF_X86_EVENT_PEBS_STLAT is
introduced to indicate the event. The store_latency_data() is introduced
to parse the memory auxiliary info.

The layout of access latency field of PEBS Memory Info Record has been
changed. Two latency, instruction latency (bit 15:0) and cache access
latency (bit 47:32) are recorded.
- The cache access latency is similar to previous memory access latency.
  For loads, the latency starts by the actual cache access until the
  data is returned by the memory subsystem.
  For stores, the latency starts when the demand write accesses the L1
  data cache and lasts until the cacheline write is completed in the
  memory subsystem.
  The cache access latency is stored in low 32bits of the sample type
  PERF_SAMPLE_WEIGHT_STRUCT.
- The instruction latency starts by the dispatch of the load operation
  for execution and lasts until completion of the instruction it belongs
  to.
  Add a new flag PMU_FL_INSTR_LATENCY to indicate the instruction
  latency support. The instruction latency is stored in the bit 47:32
  of the sample type PERF_SAMPLE_WEIGHT_STRUCT.

Extends the PERF_METRICS MSR to feature TMA method level 2 metrics. The
lower half of the register is the TMA level 1 metrics (legacy). The
upper half is also divided into four 8-bit fields for the new level 2
metrics. Expose all eight Topdown metrics events to user space.

The full description for the SPR features can be found at Intel
Architecture Instruction Set Extensions and Future Features
Programming Reference, 319433-041.
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1611873611-156687-5-git-send-email-kan.liang@linux.intel.com
      61b985e3
    • K
      perf/x86/intel: Filter unsupported Topdown metrics event · 1ab5f235
      由 Kan Liang 提交于 
      Intel Sapphire Rapids server will introduce 8 metrics events. Intel
Ice Lake only supports 4 metrics events. A perf tool user may mistakenly
use the unsupported events via RAW format on Ice Lake. The user can
still get a value from the unsupported Topdown metrics event once the
following Sapphire Rapids enabling patch is applied.

To enable the 8 metrics events on Intel Sapphire Rapids, the
INTEL_TD_METRIC_MAX has to be updated, which impacts the
is_metric_event(). The is_metric_event() is a generic function.
On Ice Lake, the newly added SPR metrics events will be mistakenly
accepted as metric events on creation. At runtime, the unsupported
Topdown metrics events will be updated.

Add a variable num_topdown_events in x86_pmu to indicate the available
number of the Topdown metrics event on the platform. Apply the number
into is_metric_event(). Only the supported Topdown metrics events
should be created as metrics events.

Apply the num_topdown_events in icl_update_topdown_event() as well. The
function can be reused by the following patch.
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>
Link: https://lkml.kernel.org/r/1611873611-156687-4-git-send-email-kan.liang@linux.intel.com
      1ab5f235
    • K
      perf/x86/intel: Factor out intel_update_topdown_event() · 628d923a
      由 Kan Liang 提交于 
      Similar to Ice Lake, Intel Sapphire Rapids server also supports the
topdown performance metrics feature. The difference is that Intel
Sapphire Rapids server extends the PERF_METRICS MSR to feature TMA
method level two metrics, which will introduce 8 metrics events. Current
icl_update_topdown_event() only check 4 level one metrics events.

Factor out intel_update_topdown_event() to facilitate the code sharing
between Ice Lake and Sapphire Rapids.
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1611873611-156687-3-git-send-email-kan.liang@linux.intel.com
      628d923a
  9. 28 1月, 2021 2 次提交
  11. 10 12月, 2020 2 次提交
  13. 10 11月, 2020 2 次提交
  15. 29 10月, 2020 2 次提交
  17. 03 10月, 2020 1 次提交
  19. 29 9月, 2020 2 次提交
  21. 24 8月, 2020 1 次提交
  23. 18 8月, 2020 5 次提交
    • K
      perf/x86/intel: Support per-thread RDPMC TopDown metrics · 2cb5383b
      由 Kan Liang 提交于 
      Starts from Ice Lake, the TopDown metrics are directly available as
fixed counters and do not require generic counters. Also, the TopDown
metrics can be collected per thread. Extend the RDPMC usage to support
per-thread TopDown metrics.

The RDPMC index of the PERF_METRICS will be output if RDPMC users ask
for the RDPMC index of the metrics events.

To support per thread RDPMC TopDown, the metrics and slots counters have
to be saved/restored during the context switching.

The last_period and period_left are not used in the counting mode. Use
the fields for saved_metric and saved_slots.
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200723171117.9918-12-kan.liang@linux.intel.com
      2cb5383b
    • K
      perf/x86/intel: Support TopDown metrics on Ice Lake · 59a854e2
      由 Kan Liang 提交于 
      Ice Lake supports the hardware TopDown metrics feature, which can free
up the scarce GP counters.

Update the event constraints for the metrics events. The metric counters
do not exist, which are mapped to a dummy offset. The sharing between
multiple users of the same metric without multiplexing is not allowed.

Implement set_topdown_event_period for Ice Lake. The values in
PERF_METRICS MSR are derived from the fixed counter 3. Both registers
should start from zero.

Implement update_topdown_event for Ice Lake. The metric is reported by
multiplying the metric (fraction) with slots. To maintain accurate
measurements, both registers are cleared for each update. The fixed
counter 3 should always be cleared before the PERF_METRICS.

Implement td_attr for the new metrics events and the new slots fixed
counter. Make them visible to the perf user tools.
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200723171117.9918-11-kan.liang@linux.intel.com
      59a854e2
    • K
      perf/x86/intel: Generic support for hardware TopDown metrics · 7b2c05a1
      由 Kan Liang 提交于 
      Intro
=====

The TopDown Microarchitecture Analysis (TMA) Method is a structured
analysis methodology to identify critical performance bottlenecks in
out-of-order processors. Current perf has supported the method.

The method works well, but there is one problem. To collect the TopDown
events, several GP counters have to be used. If a user wants to collect
other events at the same time, the multiplexing probably be triggered,
which impacts the accuracy.

To free up the scarce GP counters, the hardware TopDown metrics feature
is introduced from Ice Lake. The hardware implements an additional
"metrics" register and a new Fixed Counter 3 that measures pipeline
"slots". The TopDown events can be calculated from them instead.

Events
======

The level 1 TopDown has four metrics. There is no event-code assigned to
the TopDown metrics. Four metric events are exported as separate perf
events, which map to the internal "metrics" counter register. Those
events do not exist in hardware, but can be allocated by the scheduler.

For the event mapping, a special 0x00 event code is used, which is
reserved for fake events. The metric events start from umask 0x10.

When setting up the metric events, they point to the Fixed Counter 3.
They have to be specially handled.
- Add the update_topdown_event() callback to read the additional metrics
  MSR and generate the metrics.
- Add the set_topdown_event_period() callback to initialize metrics MSR
  and the fixed counter 3.
- Add a variable n_metric_event to track the number of the accepted
  metrics events. The sharing between multiple users of the same metric
  without multiplexing is not allowed.
- Only enable/disable the fixed counter 3 when there are no other active
  TopDown events, which avoid the unnecessary writing of the fixed
  control register.
- Disable the PMU when reading the metrics event. The metrics MSR and
  the fixed counter 3 are read separately. The values may be modified by
  an NMI.

All four metric events don't support sampling. Since they will be
handled specially for event update, a flag PERF_X86_EVENT_TOPDOWN is
introduced to indicate this case.

The slots event can support both sampling and counting.
For counting, the flag is also applied.
For sampling, it will be handled normally as other normal events.

Groups
======

The slots event is required in a Topdown group.
To avoid reading the METRICS register multiple times, the metrics and
slots value can only be updated by slots event in a group.
All active slots and metrics events will be updated one time.
Therefore, the slots event must be before any metric events in a Topdown
group.

NMI
======

The METRICS related register may be overflow. The bit 48 of the STATUS
register will be set. If so, PERF_METRICS and Fixed counter 3 are
required to be reset. The patch also update all active slots and
metrics events in the NMI handler.

The update_topdown_event() has to read two registers separately. The
values may be modified by an NMI. PMU has to be disabled before calling
the function.

RDPMC
======

RDPMC is temporarily disabled. A later patch will enable it.
Suggested-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200723171117.9918-9-kan.liang@linux.intel.com
      7b2c05a1
    • K
      perf/x86/intel: Use switch in intel_pmu_disable/enable_event · 58da7dbe
      由 Kan Liang 提交于 
      Currently, the if-else is used in the intel_pmu_disable/enable_event to
check the type of an event. It works well, but with more and more types
added later, e.g., perf metrics, compared to the switch statement, the
if-else may impair the readability of the code.

There is no harm to use the switch statement to replace the if-else
here. Also, some optimizing compilers may compile a switch statement
into a jump-table which is more efficient than if-else for a large
number of cases. The performance gain may not be observed for now,
because the number of cases is only 5, but the benefits may be observed
with more and more types added in the future.

Use switch to replace the if-else in the intel_pmu_disable/enable_event.

If the idx is invalid, print a warning.

For the case INTEL_PMC_IDX_FIXED_BTS in intel_pmu_disable_event, don't
need to check the event->attr.precise_ip. Use return for the case.
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200723171117.9918-7-kan.liang@linux.intel.com
      58da7dbe
    • K
      perf/x86/intel: Name the global status bit in NMI handler · 60a2a271
      由 Kan Liang 提交于 
      Magic numbers are used in the current NMI handler for the global status
bit. Use a meaningful name to replace the magic numbers to improve the
readability of the code.

Remove a Tab for all GLOBAL_STATUS_* and INTEL_PMC_IDX_FIXED_BTS macros
to reduce the length of the line.
Suggested-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200723171117.9918-3-kan.liang@linux.intel.com
      60a2a271
  25. 08 7月, 2020 4 次提交
    • K
      perf/x86/intel/lbr: Support Architectural LBR · 47125db2
      由 Kan Liang 提交于 
      Last Branch Records (LBR) enables recording of software path history by
logging taken branches and other control flows within architectural
registers now. Intel CPUs have had model-specific LBR for quite some
time, but this evolves them into an architectural feature now.

The main improvements of Architectural LBR implemented includes:
- Linux kernel can support the LBR features without knowing the model
  number of the current CPU.
- Architectural LBR capabilities can be enumerated by CPUID. The
  lbr_ctl_map is based on the CPUID Enumeration.
- The possible LBR depth can be retrieved from CPUID enumeration. The
  max value is written to the new MSR_ARCH_LBR_DEPTH as the number of
  LBR entries.
- A new IA32_LBR_CTL MSR is introduced to enable and configure LBRs,
  which replaces the IA32_DEBUGCTL[bit 0] and the LBR_SELECT MSR.
- Each LBR record or entry is still comprised of three MSRs,
  IA32_LBR_x_FROM_IP, IA32_LBR_x_TO_IP and IA32_LBR_x_TO_IP.
  But they become the architectural MSRs.
- Architectural LBR is stack-like now. Entry 0 is always the youngest
  branch, entry 1 the next youngest... The TOS MSR has been removed.

The way to enable/disable Architectural LBR is similar to the previous
model-specific LBR. __intel_pmu_lbr_enable/disable() can be reused, but
some modifications are required, which include:
- MSR_ARCH_LBR_CTL is used to enable and configure the Architectural
  LBR.
- When checking the value of the IA32_DEBUGCTL MSR, ignoring the
  DEBUGCTLMSR_LBR (bit 0) for Architectural LBR, which has no meaning
  and always return 0.
- The FREEZE_LBRS_ON_PMI has to be explicitly set/clear, because
  MSR_IA32_DEBUGCTLMSR is not touched in __intel_pmu_lbr_disable() for
  Architectural LBR.
- Only MSR_ARCH_LBR_CTL is cleared in __intel_pmu_lbr_disable() for
  Architectural LBR.

Some Architectural LBR dedicated functions are implemented to
reset/read/save/restore LBR.
- For reset, writing to the ARCH_LBR_DEPTH MSR clears all Arch LBR
  entries, which is a lot faster and can improve the context switch
  latency.
- For read, the branch type information can be retrieved from
  the MSR_ARCH_LBR_INFO_*. But it's not fully compatible due to
  OTHER_BRANCH type. The software decoding is still required for the
  OTHER_BRANCH case.
  LBR records are stored in the age order as well. Reuse
  intel_pmu_store_lbr(). Check the CPUID enumeration before accessing
  the corresponding bits in LBR_INFO.
- For save/restore, applying the fast reset (writing ARCH_LBR_DEPTH).
  Reading 'lbr_from' of entry 0 instead of the TOS MSR to check if the
  LBR registers are reset in the deep C-state. If 'the deep C-state
  reset' bit is not set in CPUID enumeration, ignoring the check.
  XSAVE support for Architectural LBR will be implemented later.

The number of LBR entries cannot be hardcoded anymore, which should be
retrieved from CPUID enumeration. A new structure
x86_perf_task_context_arch_lbr is introduced for Architectural LBR.
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1593780569-62993-15-git-send-email-kan.liang@linux.intel.com
      47125db2
    • K
      perf/x86/intel/lbr: Add the function pointers for LBR save and restore · 799571bf
      由 Kan Liang 提交于 
      The MSRs of Architectural LBR are different from previous model-specific
LBR. Perf has to implement different functions to save and restore them.

The function pointers for LBR save and restore are introduced. Perf
should initialize the corresponding functions at boot time.

The generic optimizations, e.g. avoiding restore LBR if no one else
touched them, still apply for Architectural LBRs. The related codes are
not moved to model-specific functions.

Current model-specific LBR functions are set as default.
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1593780569-62993-5-git-send-email-kan.liang@linux.intel.com
      799571bf
    • K
      perf/x86/intel/lbr: Add a function pointer for LBR read · c301b1d8
      由 Kan Liang 提交于 
      The method to read Architectural LBRs is different from previous
model-specific LBR. Perf has to implement a different function.

A function pointer for LBR read is introduced. Perf should initialize
the corresponding function at boot time, and avoid checking lbr_format
at run time.

The current 64-bit LBR read function is set as default.
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1593780569-62993-4-git-send-email-kan.liang@linux.intel.com
      c301b1d8
    • K
      perf/x86/intel/lbr: Add a function pointer for LBR reset · 9f354a72
      由 Kan Liang 提交于 
      The method to reset Architectural LBRs is different from previous
model-specific LBR. Perf has to implement a different function.

A function pointer is introduced for LBR reset. The enum of
LBR_FORMAT_* is also moved to perf_event.h. Perf should initialize the
corresponding functions at boot time, and avoid checking lbr_format at
run time.

The current 64-bit LBR reset function is set as default.
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1593780569-62993-3-git-send-email-kan.liang@linux.intel.com
      9f354a72
  27. 02 7月, 2020 3 次提交