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[v5,00/12] perf/core: Generalise event exclusion checking

Message ID 1547128414-50693-1-git-send-email-andrew.murray@arm.com
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Series perf/core: Generalise event exclusion checking | expand


Andrew Murray Jan. 10, 2019, 1:53 p.m. UTC
Many PMU drivers do not have the capability to exclude counting events
that occur in specific contexts such as idle, kernel, guest, etc. These
drivers indicate this by returning an error in their event_init upon
testing the events attribute flags.

However this approach requires that each time a new event modifier is
added to perf, all the perf drivers need to be modified to indicate that
they don't support the attribute. This results in additional boiler-plate
code common to many drivers that needs to be maintained. Furthermore the
drivers are not consistent with regards to the error value they return
when reporting unsupported attributes.

This patchset allow PMU drivers to advertise their inability to exclude
based on context via a new capability: PERF_PMU_CAP_NO_EXCLUDE. This
allows the perf core to reject requests for exclusion events where there
is no support in the PMU.

This is a functional change, in particular:

 - Some drivers will now additionally (but correctly) report unsupported
   exclusion flags. It's typical for existing userspace tools such as
   perf to handle such errors by retrying the system call without the
   unsupported flags.

 - Drivers that do not support any exclusion that previously reported
   -EPERM or -EOPNOTSUPP will now report -EINVAL - this is consistent
   with the majority and results in userspace perf retrying without

All drivers touched by this patchset have been compile tested.

Changes from v4:

 - Squashed Cavium TX2 patch into drivers/perf patch
 - Removed duplicate patch subjects by using 'strengthen ..' wording to
   indicate patches that use PERF_PMU_CAP_NO_EXCLUDE which make behavioural
 - Added additional information to commit messages

Changes from v3:

 - Added PERF_PMU_CAP_NO_EXCLUDE to Cavium TX2 PMU driver

Changes from v2:

 - Invert logic from CAP_EXCLUDE to CAP_NO_EXCLUDE

Changes from v1:

 - Changed approach from explicitly rejecting events in unsupporting PMU
   drivers to explicitly advertising a capability in PMU drivers that
   do support exclusion events

 - Added additional information to tools/perf/design.txt

 - Rename event_has_exclude_flags to event_has_any_exclude_flag and
   update commit log to reflect it's a function

Andrew Murray (12):
  perf/doc: update design.txt for exclude_{host|guest} flags
  perf/core: add function to test for event exclusion flags
  perf/core: add PERF_PMU_CAP_NO_EXCLUDE for exclusion incapable PMUs
  alpha: perf/core: strengthen exclude checks with
  arm: perf: conditionally use PERF_PMU_CAP_NO_EXCLUDE
  arm: perf/core: use PERF_PMU_CAP_NO_EXCLUDE for exclude incapable PMUs
  drivers/perf: perf/core: use PERF_PMU_CAP_NO_EXCLUDE for exclude
    incapable PMUs
  drivers/perf: perf/core: strengthen exclude checks with
  powerpc: perf/core: use PERF_PMU_CAP_NO_EXCLUDE for exclude incapable
  x86: perf/core: use PERF_PMU_CAP_NO_EXCLUDE for exclude incapable PMUs
  x86: perf/core: strengthen exclude checks with PERF_PMU_CAP_NO_EXCLUDE
  perf/core: remove unused perf_flags

 arch/alpha/kernel/perf_event.c                |  7 +------
 arch/arm/mach-imx/mmdc.c                      |  9 ++-------
 arch/arm/mm/cache-l2x0-pmu.c                  |  9 +--------
 arch/powerpc/perf/hv-24x7.c                   | 10 +---------
 arch/powerpc/perf/hv-gpci.c                   | 10 +---------
 arch/powerpc/perf/imc-pmu.c                   | 19 +------------------
 arch/x86/events/amd/ibs.c                     | 13 +------------
 arch/x86/events/amd/iommu.c                   |  6 +-----
 arch/x86/events/amd/power.c                   | 10 ++--------
 arch/x86/events/amd/uncore.c                  |  7 ++-----
 arch/x86/events/intel/cstate.c                | 12 +++---------
 arch/x86/events/intel/rapl.c                  |  9 ++-------
 arch/x86/events/intel/uncore.c                |  9 +--------
 arch/x86/events/intel/uncore_snb.c            |  9 ++-------
 arch/x86/events/msr.c                         | 10 ++--------
 drivers/perf/arm-cci.c                        | 10 +---------
 drivers/perf/arm-ccn.c                        |  6 ++----
 drivers/perf/arm_dsu_pmu.c                    |  9 ++-------
 drivers/perf/arm_pmu.c                        | 15 +++++----------
 drivers/perf/hisilicon/hisi_uncore_ddrc_pmu.c |  1 +
 drivers/perf/hisilicon/hisi_uncore_hha_pmu.c  |  1 +
 drivers/perf/hisilicon/hisi_uncore_l3c_pmu.c  |  1 +
 drivers/perf/hisilicon/hisi_uncore_pmu.c      |  9 ---------
 drivers/perf/qcom_l2_pmu.c                    |  9 +--------
 drivers/perf/qcom_l3_pmu.c                    |  8 +-------
 drivers/perf/thunderx2_pmu.c                  | 10 +---------
 drivers/perf/xgene_pmu.c                      |  6 +-----
 include/linux/perf_event.h                    | 10 ++++++++++
 include/uapi/linux/perf_event.h               |  2 --
 kernel/events/core.c                          |  9 +++++++++
 tools/include/uapi/linux/perf_event.h         |  2 --
 tools/perf/design.txt                         |  4 ++++
 32 files changed, 63 insertions(+), 198 deletions(-)