| Message ID | 1544114849-47266-1-git-send-email-andrew.murray@arm.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | perf/core: Generalise event exclusion checking | expand |
On Thu, Dec 06, 2018 at 04:47:17PM +0000, Andrew Murray wrote: > 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 > exclusion. > > All drivers touched by this patchset have been compile tested. For the bits under arch/arm/ and drivers/perf: Acked-by: Will Deacon <will.deacon@arm.com> Note that I've queued the TX2 uncore PMU for 4.21 [1], which could also benefit from your new flag. Will [1] https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/commit/?h=for-next/perf&id=69c32972d59388c041268e8206e8eb1acff29b9a
On Fri, Dec 07, 2018 at 05:25:17PM +0000, Will Deacon wrote: > On Thu, Dec 06, 2018 at 04:47:17PM +0000, Andrew Murray wrote: > > 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 > > exclusion. > > > > All drivers touched by this patchset have been compile tested. > > For the bits under arch/arm/ and drivers/perf: > > Acked-by: Will Deacon <will.deacon@arm.com> > > Note that I've queued the TX2 uncore PMU for 4.21 [1], which could also > benefit from your new flag. Ah thanks for pointing this out, I'll send a patch in due course. Thanks, Andrwe Murray > > Will > > [1] > https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/commit/?h=for-next/perf&id=69c32972d59388c041268e8206e8eb1acff29b9a
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 exclusion. All drivers touched by this patchset have been compile tested. 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: use PERF_PMU_CAP_NO_EXCLUDE 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: use PERF_PMU_CAP_NO_EXCLUDE for exclude incapable PMUs powerpc: perf/core: use PERF_PMU_CAP_NO_EXCLUDE for exclude incapable PMUs x86: perf/core: use PERF_PMU_CAP_NO_EXCLUDE for exclude incapable PMUs x86: perf/core: use PERF_PMU_CAP_NO_EXCLUDE for exclude incapable PMUs 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/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 ++++ 31 files changed, 62 insertions(+), 189 deletions(-)