| Message ID | 20220518085502.6914-1-atrajeev@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [V2,1/2] powerpc/perf: Add support for caps under sysfs in powerpc | expand |
On Wed, May 18, 2022 at 1:55 AM Athira Rajeev <atrajeev@linux.vnet.ibm.com> wrote: > > Add caps support under "/sys/bus/event_source/devices/<pmu>/" > for powerpc. This directory can be used to expose some of the > specific features that powerpc PMU supports to the user. > Example: pmu_name. The name of PMU registered will depend on > platform, say power9 or power10 or it could be Generic Compat > PMU. > > Currently the only way to know which is the registered > PMU is from the dmesg logs. But clearing the dmesg will make it > difficult to know exact PMU backend used. And even extracting > from dmesg will be complicated, as we need to parse the dmesg > logs and add filters for pmu name. Whereas by exposing it via > caps will make it easy as we just need to directly read it from > the sysfs. For ARM and x86 in the perf tool this is normally done through a cpuid like function, is there a reason to differ on Power? Thanks, Ian > Add a caps directory to /sys/bus/event_source/devices/cpu/ > for power8, power9, power10 and generic compat PMU in respective > PMU driver code. Update the pmu_name file under caps folder > in core-book3s using "attr_update". > > The information exposed currently: > - pmu_name : Underlying PMU name from the driver > > Example result with power9 pmu: > > # ls /sys/bus/event_source/devices/cpu/caps > pmu_name > > # cat /sys/bus/event_source/devices/cpu/caps/pmu_name > POWER9 > > Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> > --- > Changelog: > v1 -> v2: > Move the show function as generic in core-book3s > and update show function using sysfs_emit and ppmu->name > Added Documention for this ABI in patch 2. > Notes: The caps directory is implemented in PMU for other > architectures already. Reference commit for x86: > commit b00233b53065 ("perf/x86: Export some PMU attributes in caps/ directory") > > arch/powerpc/perf/core-book3s.c | 31 ++++++++++++++++++++++++++ > arch/powerpc/perf/generic-compat-pmu.c | 10 +++++++++ > arch/powerpc/perf/power10-pmu.c | 10 +++++++++ > arch/powerpc/perf/power8-pmu.c | 10 +++++++++ > arch/powerpc/perf/power9-pmu.c | 10 +++++++++ > 5 files changed, 71 insertions(+) > > diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c > index b5b42cf0a703..a208f502a80b 100644 > --- a/arch/powerpc/perf/core-book3s.c > +++ b/arch/powerpc/perf/core-book3s.c > @@ -2488,6 +2488,33 @@ static int power_pmu_prepare_cpu(unsigned int cpu) > return 0; > } > > +static ssize_t pmu_name_show(struct device *cdev, > + struct device_attribute *attr, > + char *buf) > +{ > + if (ppmu) > + return sysfs_emit(buf, "%s\n", ppmu->name); > + > + return 0; > +} > + > +static DEVICE_ATTR_RO(pmu_name); > + > +static struct attribute *pmu_caps_attrs[] = { > + &dev_attr_pmu_name.attr, > + NULL > +}; > + > +static const struct attribute_group pmu_caps_group = { > + .name = "caps", > + .attrs = pmu_caps_attrs, > +}; > + > +static const struct attribute_group *pmu_caps_groups[] = { > + &pmu_caps_group, > + NULL, > +}; > + > int __init register_power_pmu(struct power_pmu *pmu) > { > if (ppmu) > @@ -2498,6 +2525,10 @@ int __init register_power_pmu(struct power_pmu *pmu) > pmu->name); > > power_pmu.attr_groups = ppmu->attr_groups; > + > + if (ppmu->flags & PPMU_ARCH_207S) > + power_pmu.attr_update = pmu_caps_groups; > + > power_pmu.capabilities |= (ppmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS); > > #ifdef MSR_HV > diff --git a/arch/powerpc/perf/generic-compat-pmu.c b/arch/powerpc/perf/generic-compat-pmu.c > index f3db88aee4dd..817c69863038 100644 > --- a/arch/powerpc/perf/generic-compat-pmu.c > +++ b/arch/powerpc/perf/generic-compat-pmu.c > @@ -151,9 +151,19 @@ static const struct attribute_group generic_compat_pmu_format_group = { > .attrs = generic_compat_pmu_format_attr, > }; > > +static struct attribute *generic_compat_pmu_caps_attrs[] = { > + NULL > +}; > + > +static struct attribute_group generic_compat_pmu_caps_group = { > + .name = "caps", > + .attrs = generic_compat_pmu_caps_attrs, > +}; > + > static const struct attribute_group *generic_compat_pmu_attr_groups[] = { > &generic_compat_pmu_format_group, > &generic_compat_pmu_events_group, > + &generic_compat_pmu_caps_group, > NULL, > }; > > diff --git a/arch/powerpc/perf/power10-pmu.c b/arch/powerpc/perf/power10-pmu.c > index c6d51e7093cf..d1adcd9f52e2 100644 > --- a/arch/powerpc/perf/power10-pmu.c > +++ b/arch/powerpc/perf/power10-pmu.c > @@ -258,6 +258,15 @@ static const struct attribute_group power10_pmu_format_group = { > .attrs = power10_pmu_format_attr, > }; > > +static struct attribute *power10_pmu_caps_attrs[] = { > + NULL > +}; > + > +static struct attribute_group power10_pmu_caps_group = { > + .name = "caps", > + .attrs = power10_pmu_caps_attrs, > +}; > + > static const struct attribute_group *power10_pmu_attr_groups_dd1[] = { > &power10_pmu_format_group, > &power10_pmu_events_group_dd1, > @@ -267,6 +276,7 @@ static const struct attribute_group *power10_pmu_attr_groups_dd1[] = { > static const struct attribute_group *power10_pmu_attr_groups[] = { > &power10_pmu_format_group, > &power10_pmu_events_group, > + &power10_pmu_caps_group, > NULL, > }; > > diff --git a/arch/powerpc/perf/power8-pmu.c b/arch/powerpc/perf/power8-pmu.c > index e37b1e714d2b..2518f5375d4a 100644 > --- a/arch/powerpc/perf/power8-pmu.c > +++ b/arch/powerpc/perf/power8-pmu.c > @@ -187,9 +187,19 @@ static const struct attribute_group power8_pmu_events_group = { > .attrs = power8_events_attr, > }; > > +static struct attribute *power8_pmu_caps_attrs[] = { > + NULL > +}; > + > +static struct attribute_group power8_pmu_caps_group = { > + .name = "caps", > + .attrs = power8_pmu_caps_attrs, > +}; > + > static const struct attribute_group *power8_pmu_attr_groups[] = { > &isa207_pmu_format_group, > &power8_pmu_events_group, > + &power8_pmu_caps_group, > NULL, > }; > > diff --git a/arch/powerpc/perf/power9-pmu.c b/arch/powerpc/perf/power9-pmu.c > index c393e837648e..5c654ce1a417 100644 > --- a/arch/powerpc/perf/power9-pmu.c > +++ b/arch/powerpc/perf/power9-pmu.c > @@ -258,9 +258,19 @@ static const struct attribute_group power9_pmu_format_group = { > .attrs = power9_pmu_format_attr, > }; > > +static struct attribute *power9_pmu_caps_attrs[] = { > + NULL > +}; > + > +static struct attribute_group power9_pmu_caps_group = { > + .name = "caps", > + .attrs = power9_pmu_caps_attrs, > +}; > + > static const struct attribute_group *power9_pmu_attr_groups[] = { > &power9_pmu_format_group, > &power9_pmu_events_group, > + &power9_pmu_caps_group, > NULL, > }; > > -- > 2.31.1 >
> On 19-May-2022, at 10:12 AM, Ian Rogers <irogers@google.com> wrote: > > On Wed, May 18, 2022 at 1:55 AM Athira Rajeev > <atrajeev@linux.vnet.ibm.com> wrote: >> >> Add caps support under "/sys/bus/event_source/devices/<pmu>/" >> for powerpc. This directory can be used to expose some of the >> specific features that powerpc PMU supports to the user. >> Example: pmu_name. The name of PMU registered will depend on >> platform, say power9 or power10 or it could be Generic Compat >> PMU. >> >> Currently the only way to know which is the registered >> PMU is from the dmesg logs. But clearing the dmesg will make it >> difficult to know exact PMU backend used. And even extracting >> from dmesg will be complicated, as we need to parse the dmesg >> logs and add filters for pmu name. Whereas by exposing it via >> caps will make it easy as we just need to directly read it from >> the sysfs. > > For ARM and x86 in the perf tool this is normally done through a cpuid > like function, is there a reason to differ on Power? > > Thanks, > Ian Hi Ian, Thanks for review. The information from cpuid or cpuinfo will provide us the information of the platform/model/machine etc. In case of powerpc, we have one case where, though platform points to specific generation of the processor, say power9 or power10, the registered PMU could point to different one. To be specific, this is named as Generic Compat PMU which is a fallback PMU. This gets registered when the distro doesn't have support for platform specific PMU. In that case distro will have a Generic Compat PMU registered which supports basic features for performance monitoring. This information can't be fetched from the cpuid data since that will point to current platform. So the pmu_name exposed via "caps" will be useful to detect the PMU registered and also we target to use this information in some of our selftests. Thanks Athira > >> Add a caps directory to /sys/bus/event_source/devices/cpu/ >> for power8, power9, power10 and generic compat PMU in respective >> PMU driver code. Update the pmu_name file under caps folder >> in core-book3s using "attr_update". >> >> The information exposed currently: >> - pmu_name : Underlying PMU name from the driver >> >> Example result with power9 pmu: >> >> # ls /sys/bus/event_source/devices/cpu/caps >> pmu_name >> >> # cat /sys/bus/event_source/devices/cpu/caps/pmu_name >> POWER9 >> >> Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> >> --- >> Changelog: >> v1 -> v2: >> Move the show function as generic in core-book3s >> and update show function using sysfs_emit and ppmu->name >> Added Documention for this ABI in patch 2. >> Notes: The caps directory is implemented in PMU for other >> architectures already. Reference commit for x86: >> commit b00233b53065 ("perf/x86: Export some PMU attributes in caps/ directory") >> >> arch/powerpc/perf/core-book3s.c | 31 ++++++++++++++++++++++++++ >> arch/powerpc/perf/generic-compat-pmu.c | 10 +++++++++ >> arch/powerpc/perf/power10-pmu.c | 10 +++++++++ >> arch/powerpc/perf/power8-pmu.c | 10 +++++++++ >> arch/powerpc/perf/power9-pmu.c | 10 +++++++++ >> 5 files changed, 71 insertions(+) >> >> diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c >> index b5b42cf0a703..a208f502a80b 100644 >> --- a/arch/powerpc/perf/core-book3s.c >> +++ b/arch/powerpc/perf/core-book3s.c >> @@ -2488,6 +2488,33 @@ static int power_pmu_prepare_cpu(unsigned int cpu) >> return 0; >> } >> >> +static ssize_t pmu_name_show(struct device *cdev, >> + struct device_attribute *attr, >> + char *buf) >> +{ >> + if (ppmu) >> + return sysfs_emit(buf, "%s\n", ppmu->name); >> + >> + return 0; >> +} >> + >> +static DEVICE_ATTR_RO(pmu_name); >> + >> +static struct attribute *pmu_caps_attrs[] = { >> + &dev_attr_pmu_name.attr, >> + NULL >> +}; >> + >> +static const struct attribute_group pmu_caps_group = { >> + .name = "caps", >> + .attrs = pmu_caps_attrs, >> +}; >> + >> +static const struct attribute_group *pmu_caps_groups[] = { >> + &pmu_caps_group, >> + NULL, >> +}; >> + >> int __init register_power_pmu(struct power_pmu *pmu) >> { >> if (ppmu) >> @@ -2498,6 +2525,10 @@ int __init register_power_pmu(struct power_pmu *pmu) >> pmu->name); >> >> power_pmu.attr_groups = ppmu->attr_groups; >> + >> + if (ppmu->flags & PPMU_ARCH_207S) >> + power_pmu.attr_update = pmu_caps_groups; >> + >> power_pmu.capabilities |= (ppmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS); >> >> #ifdef MSR_HV >> diff --git a/arch/powerpc/perf/generic-compat-pmu.c b/arch/powerpc/perf/generic-compat-pmu.c >> index f3db88aee4dd..817c69863038 100644 >> --- a/arch/powerpc/perf/generic-compat-pmu.c >> +++ b/arch/powerpc/perf/generic-compat-pmu.c >> @@ -151,9 +151,19 @@ static const struct attribute_group generic_compat_pmu_format_group = { >> .attrs = generic_compat_pmu_format_attr, >> }; >> >> +static struct attribute *generic_compat_pmu_caps_attrs[] = { >> + NULL >> +}; >> + >> +static struct attribute_group generic_compat_pmu_caps_group = { >> + .name = "caps", >> + .attrs = generic_compat_pmu_caps_attrs, >> +}; >> + >> static const struct attribute_group *generic_compat_pmu_attr_groups[] = { >> &generic_compat_pmu_format_group, >> &generic_compat_pmu_events_group, >> + &generic_compat_pmu_caps_group, >> NULL, >> }; >> >> diff --git a/arch/powerpc/perf/power10-pmu.c b/arch/powerpc/perf/power10-pmu.c >> index c6d51e7093cf..d1adcd9f52e2 100644 >> --- a/arch/powerpc/perf/power10-pmu.c >> +++ b/arch/powerpc/perf/power10-pmu.c >> @@ -258,6 +258,15 @@ static const struct attribute_group power10_pmu_format_group = { >> .attrs = power10_pmu_format_attr, >> }; >> >> +static struct attribute *power10_pmu_caps_attrs[] = { >> + NULL >> +}; >> + >> +static struct attribute_group power10_pmu_caps_group = { >> + .name = "caps", >> + .attrs = power10_pmu_caps_attrs, >> +}; >> + >> static const struct attribute_group *power10_pmu_attr_groups_dd1[] = { >> &power10_pmu_format_group, >> &power10_pmu_events_group_dd1, >> @@ -267,6 +276,7 @@ static const struct attribute_group *power10_pmu_attr_groups_dd1[] = { >> static const struct attribute_group *power10_pmu_attr_groups[] = { >> &power10_pmu_format_group, >> &power10_pmu_events_group, >> + &power10_pmu_caps_group, >> NULL, >> }; >> >> diff --git a/arch/powerpc/perf/power8-pmu.c b/arch/powerpc/perf/power8-pmu.c >> index e37b1e714d2b..2518f5375d4a 100644 >> --- a/arch/powerpc/perf/power8-pmu.c >> +++ b/arch/powerpc/perf/power8-pmu.c >> @@ -187,9 +187,19 @@ static const struct attribute_group power8_pmu_events_group = { >> .attrs = power8_events_attr, >> }; >> >> +static struct attribute *power8_pmu_caps_attrs[] = { >> + NULL >> +}; >> + >> +static struct attribute_group power8_pmu_caps_group = { >> + .name = "caps", >> + .attrs = power8_pmu_caps_attrs, >> +}; >> + >> static const struct attribute_group *power8_pmu_attr_groups[] = { >> &isa207_pmu_format_group, >> &power8_pmu_events_group, >> + &power8_pmu_caps_group, >> NULL, >> }; >> >> diff --git a/arch/powerpc/perf/power9-pmu.c b/arch/powerpc/perf/power9-pmu.c >> index c393e837648e..5c654ce1a417 100644 >> --- a/arch/powerpc/perf/power9-pmu.c >> +++ b/arch/powerpc/perf/power9-pmu.c >> @@ -258,9 +258,19 @@ static const struct attribute_group power9_pmu_format_group = { >> .attrs = power9_pmu_format_attr, >> }; >> >> +static struct attribute *power9_pmu_caps_attrs[] = { >> + NULL >> +}; >> + >> +static struct attribute_group power9_pmu_caps_group = { >> + .name = "caps", >> + .attrs = power9_pmu_caps_attrs, >> +}; >> + >> static const struct attribute_group *power9_pmu_attr_groups[] = { >> &power9_pmu_format_group, >> &power9_pmu_events_group, >> + &power9_pmu_caps_group, >> NULL, >> }; >> >> -- >> 2.31.1
On Thu, May 19, 2022 at 4:29 AM Athira Rajeev <atrajeev@linux.vnet.ibm.com> wrote: > > > On 19-May-2022, at 10:12 AM, Ian Rogers <irogers@google.com> wrote: > > > > On Wed, May 18, 2022 at 1:55 AM Athira Rajeev > > <atrajeev@linux.vnet.ibm.com> wrote: > >> > >> Add caps support under "/sys/bus/event_source/devices/<pmu>/" > >> for powerpc. This directory can be used to expose some of the > >> specific features that powerpc PMU supports to the user. > >> Example: pmu_name. The name of PMU registered will depend on > >> platform, say power9 or power10 or it could be Generic Compat > >> PMU. > >> > >> Currently the only way to know which is the registered > >> PMU is from the dmesg logs. But clearing the dmesg will make it > >> difficult to know exact PMU backend used. And even extracting > >> from dmesg will be complicated, as we need to parse the dmesg > >> logs and add filters for pmu name. Whereas by exposing it via > >> caps will make it easy as we just need to directly read it from > >> the sysfs. > > > > For ARM and x86 in the perf tool this is normally done through a cpuid > > like function, is there a reason to differ on Power? > > > > Thanks, > > Ian > > Hi Ian, > > Thanks for review. The information from cpuid or cpuinfo will provide > us the information of the platform/model/machine etc. In case of powerpc, > we have one case where, though platform points to specific generation of the > processor, say power9 or power10, the registered PMU could point to > different one. To be specific, this is named as Generic Compat PMU which > is a fallback PMU. This gets registered when the distro doesn't have support > for platform specific PMU. In that case distro will have a Generic > Compat PMU registered which supports basic features for performance monitoring. > This information can't be fetched from the cpuid data since that will point > to current platform. > > So the pmu_name exposed via "caps" will be useful to detect the PMU > registered and also we target to use this information in some of our > selftests. Thanks, I've no problem with the change. Do we need to do a similar discovery in the perf tool on old kernels? Perhaps then this information could be exposed in the perf list command for self tests. Thanks, Ian > Thanks > Athira > > > >> Add a caps directory to /sys/bus/event_source/devices/cpu/ > >> for power8, power9, power10 and generic compat PMU in respective > >> PMU driver code. Update the pmu_name file under caps folder > >> in core-book3s using "attr_update". > >> > >> The information exposed currently: > >> - pmu_name : Underlying PMU name from the driver > >> > >> Example result with power9 pmu: > >> > >> # ls /sys/bus/event_source/devices/cpu/caps > >> pmu_name > >> > >> # cat /sys/bus/event_source/devices/cpu/caps/pmu_name > >> POWER9 > >> > >> Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> > >> --- > >> Changelog: > >> v1 -> v2: > >> Move the show function as generic in core-book3s > >> and update show function using sysfs_emit and ppmu->name > >> Added Documention for this ABI in patch 2. > >> Notes: The caps directory is implemented in PMU for other > >> architectures already. Reference commit for x86: > >> commit b00233b53065 ("perf/x86: Export some PMU attributes in caps/ directory") > >> > >> arch/powerpc/perf/core-book3s.c | 31 ++++++++++++++++++++++++++ > >> arch/powerpc/perf/generic-compat-pmu.c | 10 +++++++++ > >> arch/powerpc/perf/power10-pmu.c | 10 +++++++++ > >> arch/powerpc/perf/power8-pmu.c | 10 +++++++++ > >> arch/powerpc/perf/power9-pmu.c | 10 +++++++++ > >> 5 files changed, 71 insertions(+) > >> > >> diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c > >> index b5b42cf0a703..a208f502a80b 100644 > >> --- a/arch/powerpc/perf/core-book3s.c > >> +++ b/arch/powerpc/perf/core-book3s.c > >> @@ -2488,6 +2488,33 @@ static int power_pmu_prepare_cpu(unsigned int cpu) > >> return 0; > >> } > >> > >> +static ssize_t pmu_name_show(struct device *cdev, > >> + struct device_attribute *attr, > >> + char *buf) > >> +{ > >> + if (ppmu) > >> + return sysfs_emit(buf, "%s\n", ppmu->name); > >> + > >> + return 0; > >> +} > >> + > >> +static DEVICE_ATTR_RO(pmu_name); > >> + > >> +static struct attribute *pmu_caps_attrs[] = { > >> + &dev_attr_pmu_name.attr, > >> + NULL > >> +}; > >> + > >> +static const struct attribute_group pmu_caps_group = { > >> + .name = "caps", > >> + .attrs = pmu_caps_attrs, > >> +}; > >> + > >> +static const struct attribute_group *pmu_caps_groups[] = { > >> + &pmu_caps_group, > >> + NULL, > >> +}; > >> + > >> int __init register_power_pmu(struct power_pmu *pmu) > >> { > >> if (ppmu) > >> @@ -2498,6 +2525,10 @@ int __init register_power_pmu(struct power_pmu *pmu) > >> pmu->name); > >> > >> power_pmu.attr_groups = ppmu->attr_groups; > >> + > >> + if (ppmu->flags & PPMU_ARCH_207S) > >> + power_pmu.attr_update = pmu_caps_groups; > >> + > >> power_pmu.capabilities |= (ppmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS); > >> > >> #ifdef MSR_HV > >> diff --git a/arch/powerpc/perf/generic-compat-pmu.c b/arch/powerpc/perf/generic-compat-pmu.c > >> index f3db88aee4dd..817c69863038 100644 > >> --- a/arch/powerpc/perf/generic-compat-pmu.c > >> +++ b/arch/powerpc/perf/generic-compat-pmu.c > >> @@ -151,9 +151,19 @@ static const struct attribute_group generic_compat_pmu_format_group = { > >> .attrs = generic_compat_pmu_format_attr, > >> }; > >> > >> +static struct attribute *generic_compat_pmu_caps_attrs[] = { > >> + NULL > >> +}; > >> + > >> +static struct attribute_group generic_compat_pmu_caps_group = { > >> + .name = "caps", > >> + .attrs = generic_compat_pmu_caps_attrs, > >> +}; > >> + > >> static const struct attribute_group *generic_compat_pmu_attr_groups[] = { > >> &generic_compat_pmu_format_group, > >> &generic_compat_pmu_events_group, > >> + &generic_compat_pmu_caps_group, > >> NULL, > >> }; > >> > >> diff --git a/arch/powerpc/perf/power10-pmu.c b/arch/powerpc/perf/power10-pmu.c > >> index c6d51e7093cf..d1adcd9f52e2 100644 > >> --- a/arch/powerpc/perf/power10-pmu.c > >> +++ b/arch/powerpc/perf/power10-pmu.c > >> @@ -258,6 +258,15 @@ static const struct attribute_group power10_pmu_format_group = { > >> .attrs = power10_pmu_format_attr, > >> }; > >> > >> +static struct attribute *power10_pmu_caps_attrs[] = { > >> + NULL > >> +}; > >> + > >> +static struct attribute_group power10_pmu_caps_group = { > >> + .name = "caps", > >> + .attrs = power10_pmu_caps_attrs, > >> +}; > >> + > >> static const struct attribute_group *power10_pmu_attr_groups_dd1[] = { > >> &power10_pmu_format_group, > >> &power10_pmu_events_group_dd1, > >> @@ -267,6 +276,7 @@ static const struct attribute_group *power10_pmu_attr_groups_dd1[] = { > >> static const struct attribute_group *power10_pmu_attr_groups[] = { > >> &power10_pmu_format_group, > >> &power10_pmu_events_group, > >> + &power10_pmu_caps_group, > >> NULL, > >> }; > >> > >> diff --git a/arch/powerpc/perf/power8-pmu.c b/arch/powerpc/perf/power8-pmu.c > >> index e37b1e714d2b..2518f5375d4a 100644 > >> --- a/arch/powerpc/perf/power8-pmu.c > >> +++ b/arch/powerpc/perf/power8-pmu.c > >> @@ -187,9 +187,19 @@ static const struct attribute_group power8_pmu_events_group = { > >> .attrs = power8_events_attr, > >> }; > >> > >> +static struct attribute *power8_pmu_caps_attrs[] = { > >> + NULL > >> +}; > >> + > >> +static struct attribute_group power8_pmu_caps_group = { > >> + .name = "caps", > >> + .attrs = power8_pmu_caps_attrs, > >> +}; > >> + > >> static const struct attribute_group *power8_pmu_attr_groups[] = { > >> &isa207_pmu_format_group, > >> &power8_pmu_events_group, > >> + &power8_pmu_caps_group, > >> NULL, > >> }; > >> > >> diff --git a/arch/powerpc/perf/power9-pmu.c b/arch/powerpc/perf/power9-pmu.c > >> index c393e837648e..5c654ce1a417 100644 > >> --- a/arch/powerpc/perf/power9-pmu.c > >> +++ b/arch/powerpc/perf/power9-pmu.c > >> @@ -258,9 +258,19 @@ static const struct attribute_group power9_pmu_format_group = { > >> .attrs = power9_pmu_format_attr, > >> }; > >> > >> +static struct attribute *power9_pmu_caps_attrs[] = { > >> + NULL > >> +}; > >> + > >> +static struct attribute_group power9_pmu_caps_group = { > >> + .name = "caps", > >> + .attrs = power9_pmu_caps_attrs, > >> +}; > >> + > >> static const struct attribute_group *power9_pmu_attr_groups[] = { > >> &power9_pmu_format_group, > >> &power9_pmu_events_group, > >> + &power9_pmu_caps_group, > >> NULL, > >> }; > >> > >> -- > >> 2.31.1 >
> On 20-May-2022, at 3:06 AM, Ian Rogers <irogers@google.com> wrote: > > On Thu, May 19, 2022 at 4:29 AM Athira Rajeev > <atrajeev@linux.vnet.ibm.com> wrote: >> >>> On 19-May-2022, at 10:12 AM, Ian Rogers <irogers@google.com> wrote: >>> >>> On Wed, May 18, 2022 at 1:55 AM Athira Rajeev >>> <atrajeev@linux.vnet.ibm.com> wrote: >>>> >>>> Add caps support under "/sys/bus/event_source/devices/<pmu>/" >>>> for powerpc. This directory can be used to expose some of the >>>> specific features that powerpc PMU supports to the user. >>>> Example: pmu_name. The name of PMU registered will depend on >>>> platform, say power9 or power10 or it could be Generic Compat >>>> PMU. >>>> >>>> Currently the only way to know which is the registered >>>> PMU is from the dmesg logs. But clearing the dmesg will make it >>>> difficult to know exact PMU backend used. And even extracting >>>> from dmesg will be complicated, as we need to parse the dmesg >>>> logs and add filters for pmu name. Whereas by exposing it via >>>> caps will make it easy as we just need to directly read it from >>>> the sysfs. >>> >>> For ARM and x86 in the perf tool this is normally done through a cpuid >>> like function, is there a reason to differ on Power? >>> >>> Thanks, >>> Ian >> >> Hi Ian, >> >> Thanks for review. The information from cpuid or cpuinfo will provide >> us the information of the platform/model/machine etc. In case of powerpc, >> we have one case where, though platform points to specific generation of the >> processor, say power9 or power10, the registered PMU could point to >> different one. To be specific, this is named as Generic Compat PMU which >> is a fallback PMU. This gets registered when the distro doesn't have support >> for platform specific PMU. In that case distro will have a Generic >> Compat PMU registered which supports basic features for performance monitoring. >> This information can't be fetched from the cpuid data since that will point >> to current platform. >> >> So the pmu_name exposed via "caps" will be useful to detect the PMU >> registered and also we target to use this information in some of our >> selftests. > > Thanks, I've no problem with the change. Do we need to do a similar > discovery in the perf tool on old kernels? Perhaps then this > information could be exposed in the perf list command for self tests. Hi Ian, Thanks for review. Thats good one to have. I see in perf tools, we are parsing caps data : "env->cpu_pmu_caps" already. I will check on how this is used and option of having in perf list. After checking, I will send a follow up patch for the same. Thanks Athira > > Thanks, > Ian > >> Thanks >> Athira >>> >>>> Add a caps directory to /sys/bus/event_source/devices/cpu/ >>>> for power8, power9, power10 and generic compat PMU in respective >>>> PMU driver code. Update the pmu_name file under caps folder >>>> in core-book3s using "attr_update". >>>> >>>> The information exposed currently: >>>> - pmu_name : Underlying PMU name from the driver >>>> >>>> Example result with power9 pmu: >>>> >>>> # ls /sys/bus/event_source/devices/cpu/caps >>>> pmu_name >>>> >>>> # cat /sys/bus/event_source/devices/cpu/caps/pmu_name >>>> POWER9 >>>> >>>> Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> >>>> --- >>>> Changelog: >>>> v1 -> v2: >>>> Move the show function as generic in core-book3s >>>> and update show function using sysfs_emit and ppmu->name >>>> Added Documention for this ABI in patch 2. >>>> Notes: The caps directory is implemented in PMU for other >>>> architectures already. Reference commit for x86: >>>> commit b00233b53065 ("perf/x86: Export some PMU attributes in caps/ directory") >>>> >>>> arch/powerpc/perf/core-book3s.c | 31 ++++++++++++++++++++++++++ >>>> arch/powerpc/perf/generic-compat-pmu.c | 10 +++++++++ >>>> arch/powerpc/perf/power10-pmu.c | 10 +++++++++ >>>> arch/powerpc/perf/power8-pmu.c | 10 +++++++++ >>>> arch/powerpc/perf/power9-pmu.c | 10 +++++++++ >>>> 5 files changed, 71 insertions(+) >>>> >>>> diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c >>>> index b5b42cf0a703..a208f502a80b 100644 >>>> --- a/arch/powerpc/perf/core-book3s.c >>>> +++ b/arch/powerpc/perf/core-book3s.c >>>> @@ -2488,6 +2488,33 @@ static int power_pmu_prepare_cpu(unsigned int cpu) >>>> return 0; >>>> } >>>> >>>> +static ssize_t pmu_name_show(struct device *cdev, >>>> + struct device_attribute *attr, >>>> + char *buf) >>>> +{ >>>> + if (ppmu) >>>> + return sysfs_emit(buf, "%s\n", ppmu->name); >>>> + >>>> + return 0; >>>> +} >>>> + >>>> +static DEVICE_ATTR_RO(pmu_name); >>>> + >>>> +static struct attribute *pmu_caps_attrs[] = { >>>> + &dev_attr_pmu_name.attr, >>>> + NULL >>>> +}; >>>> + >>>> +static const struct attribute_group pmu_caps_group = { >>>> + .name = "caps", >>>> + .attrs = pmu_caps_attrs, >>>> +}; >>>> + >>>> +static const struct attribute_group *pmu_caps_groups[] = { >>>> + &pmu_caps_group, >>>> + NULL, >>>> +}; >>>> + >>>> int __init register_power_pmu(struct power_pmu *pmu) >>>> { >>>> if (ppmu) >>>> @@ -2498,6 +2525,10 @@ int __init register_power_pmu(struct power_pmu *pmu) >>>> pmu->name); >>>> >>>> power_pmu.attr_groups = ppmu->attr_groups; >>>> + >>>> + if (ppmu->flags & PPMU_ARCH_207S) >>>> + power_pmu.attr_update = pmu_caps_groups; >>>> + >>>> power_pmu.capabilities |= (ppmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS); >>>> >>>> #ifdef MSR_HV >>>> diff --git a/arch/powerpc/perf/generic-compat-pmu.c b/arch/powerpc/perf/generic-compat-pmu.c >>>> index f3db88aee4dd..817c69863038 100644 >>>> --- a/arch/powerpc/perf/generic-compat-pmu.c >>>> +++ b/arch/powerpc/perf/generic-compat-pmu.c >>>> @@ -151,9 +151,19 @@ static const struct attribute_group generic_compat_pmu_format_group = { >>>> .attrs = generic_compat_pmu_format_attr, >>>> }; >>>> >>>> +static struct attribute *generic_compat_pmu_caps_attrs[] = { >>>> + NULL >>>> +}; >>>> + >>>> +static struct attribute_group generic_compat_pmu_caps_group = { >>>> + .name = "caps", >>>> + .attrs = generic_compat_pmu_caps_attrs, >>>> +}; >>>> + >>>> static const struct attribute_group *generic_compat_pmu_attr_groups[] = { >>>> &generic_compat_pmu_format_group, >>>> &generic_compat_pmu_events_group, >>>> + &generic_compat_pmu_caps_group, >>>> NULL, >>>> }; >>>> >>>> diff --git a/arch/powerpc/perf/power10-pmu.c b/arch/powerpc/perf/power10-pmu.c >>>> index c6d51e7093cf..d1adcd9f52e2 100644 >>>> --- a/arch/powerpc/perf/power10-pmu.c >>>> +++ b/arch/powerpc/perf/power10-pmu.c >>>> @@ -258,6 +258,15 @@ static const struct attribute_group power10_pmu_format_group = { >>>> .attrs = power10_pmu_format_attr, >>>> }; >>>> >>>> +static struct attribute *power10_pmu_caps_attrs[] = { >>>> + NULL >>>> +}; >>>> + >>>> +static struct attribute_group power10_pmu_caps_group = { >>>> + .name = "caps", >>>> + .attrs = power10_pmu_caps_attrs, >>>> +}; >>>> + >>>> static const struct attribute_group *power10_pmu_attr_groups_dd1[] = { >>>> &power10_pmu_format_group, >>>> &power10_pmu_events_group_dd1, >>>> @@ -267,6 +276,7 @@ static const struct attribute_group *power10_pmu_attr_groups_dd1[] = { >>>> static const struct attribute_group *power10_pmu_attr_groups[] = { >>>> &power10_pmu_format_group, >>>> &power10_pmu_events_group, >>>> + &power10_pmu_caps_group, >>>> NULL, >>>> }; >>>> >>>> diff --git a/arch/powerpc/perf/power8-pmu.c b/arch/powerpc/perf/power8-pmu.c >>>> index e37b1e714d2b..2518f5375d4a 100644 >>>> --- a/arch/powerpc/perf/power8-pmu.c >>>> +++ b/arch/powerpc/perf/power8-pmu.c >>>> @@ -187,9 +187,19 @@ static const struct attribute_group power8_pmu_events_group = { >>>> .attrs = power8_events_attr, >>>> }; >>>> >>>> +static struct attribute *power8_pmu_caps_attrs[] = { >>>> + NULL >>>> +}; >>>> + >>>> +static struct attribute_group power8_pmu_caps_group = { >>>> + .name = "caps", >>>> + .attrs = power8_pmu_caps_attrs, >>>> +}; >>>> + >>>> static const struct attribute_group *power8_pmu_attr_groups[] = { >>>> &isa207_pmu_format_group, >>>> &power8_pmu_events_group, >>>> + &power8_pmu_caps_group, >>>> NULL, >>>> }; >>>> >>>> diff --git a/arch/powerpc/perf/power9-pmu.c b/arch/powerpc/perf/power9-pmu.c >>>> index c393e837648e..5c654ce1a417 100644 >>>> --- a/arch/powerpc/perf/power9-pmu.c >>>> +++ b/arch/powerpc/perf/power9-pmu.c >>>> @@ -258,9 +258,19 @@ static const struct attribute_group power9_pmu_format_group = { >>>> .attrs = power9_pmu_format_attr, >>>> }; >>>> >>>> +static struct attribute *power9_pmu_caps_attrs[] = { >>>> + NULL >>>> +}; >>>> + >>>> +static struct attribute_group power9_pmu_caps_group = { >>>> + .name = "caps", >>>> + .attrs = power9_pmu_caps_attrs, >>>> +}; >>>> + >>>> static const struct attribute_group *power9_pmu_attr_groups[] = { >>>> &power9_pmu_format_group, >>>> &power9_pmu_events_group, >>>> + &power9_pmu_caps_group, >>>> NULL, >>>> }; >>>> >>>> -- >>>> 2.31.1
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index b5b42cf0a703..a208f502a80b 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -2488,6 +2488,33 @@ static int power_pmu_prepare_cpu(unsigned int cpu) return 0; } +static ssize_t pmu_name_show(struct device *cdev, + struct device_attribute *attr, + char *buf) +{ + if (ppmu) + return sysfs_emit(buf, "%s\n", ppmu->name); + + return 0; +} + +static DEVICE_ATTR_RO(pmu_name); + +static struct attribute *pmu_caps_attrs[] = { + &dev_attr_pmu_name.attr, + NULL +}; + +static const struct attribute_group pmu_caps_group = { + .name = "caps", + .attrs = pmu_caps_attrs, +}; + +static const struct attribute_group *pmu_caps_groups[] = { + &pmu_caps_group, + NULL, +}; + int __init register_power_pmu(struct power_pmu *pmu) { if (ppmu) @@ -2498,6 +2525,10 @@ int __init register_power_pmu(struct power_pmu *pmu) pmu->name); power_pmu.attr_groups = ppmu->attr_groups; + + if (ppmu->flags & PPMU_ARCH_207S) + power_pmu.attr_update = pmu_caps_groups; + power_pmu.capabilities |= (ppmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS); #ifdef MSR_HV diff --git a/arch/powerpc/perf/generic-compat-pmu.c b/arch/powerpc/perf/generic-compat-pmu.c index f3db88aee4dd..817c69863038 100644 --- a/arch/powerpc/perf/generic-compat-pmu.c +++ b/arch/powerpc/perf/generic-compat-pmu.c @@ -151,9 +151,19 @@ static const struct attribute_group generic_compat_pmu_format_group = { .attrs = generic_compat_pmu_format_attr, }; +static struct attribute *generic_compat_pmu_caps_attrs[] = { + NULL +}; + +static struct attribute_group generic_compat_pmu_caps_group = { + .name = "caps", + .attrs = generic_compat_pmu_caps_attrs, +}; + static const struct attribute_group *generic_compat_pmu_attr_groups[] = { &generic_compat_pmu_format_group, &generic_compat_pmu_events_group, + &generic_compat_pmu_caps_group, NULL, }; diff --git a/arch/powerpc/perf/power10-pmu.c b/arch/powerpc/perf/power10-pmu.c index c6d51e7093cf..d1adcd9f52e2 100644 --- a/arch/powerpc/perf/power10-pmu.c +++ b/arch/powerpc/perf/power10-pmu.c @@ -258,6 +258,15 @@ static const struct attribute_group power10_pmu_format_group = { .attrs = power10_pmu_format_attr, }; +static struct attribute *power10_pmu_caps_attrs[] = { + NULL +}; + +static struct attribute_group power10_pmu_caps_group = { + .name = "caps", + .attrs = power10_pmu_caps_attrs, +}; + static const struct attribute_group *power10_pmu_attr_groups_dd1[] = { &power10_pmu_format_group, &power10_pmu_events_group_dd1, @@ -267,6 +276,7 @@ static const struct attribute_group *power10_pmu_attr_groups_dd1[] = { static const struct attribute_group *power10_pmu_attr_groups[] = { &power10_pmu_format_group, &power10_pmu_events_group, + &power10_pmu_caps_group, NULL, }; diff --git a/arch/powerpc/perf/power8-pmu.c b/arch/powerpc/perf/power8-pmu.c index e37b1e714d2b..2518f5375d4a 100644 --- a/arch/powerpc/perf/power8-pmu.c +++ b/arch/powerpc/perf/power8-pmu.c @@ -187,9 +187,19 @@ static const struct attribute_group power8_pmu_events_group = { .attrs = power8_events_attr, }; +static struct attribute *power8_pmu_caps_attrs[] = { + NULL +}; + +static struct attribute_group power8_pmu_caps_group = { + .name = "caps", + .attrs = power8_pmu_caps_attrs, +}; + static const struct attribute_group *power8_pmu_attr_groups[] = { &isa207_pmu_format_group, &power8_pmu_events_group, + &power8_pmu_caps_group, NULL, }; diff --git a/arch/powerpc/perf/power9-pmu.c b/arch/powerpc/perf/power9-pmu.c index c393e837648e..5c654ce1a417 100644 --- a/arch/powerpc/perf/power9-pmu.c +++ b/arch/powerpc/perf/power9-pmu.c @@ -258,9 +258,19 @@ static const struct attribute_group power9_pmu_format_group = { .attrs = power9_pmu_format_attr, }; +static struct attribute *power9_pmu_caps_attrs[] = { + NULL +}; + +static struct attribute_group power9_pmu_caps_group = { + .name = "caps", + .attrs = power9_pmu_caps_attrs, +}; + static const struct attribute_group *power9_pmu_attr_groups[] = { &power9_pmu_format_group, &power9_pmu_events_group, + &power9_pmu_caps_group, NULL, };
Add caps support under "/sys/bus/event_source/devices/<pmu>/" for powerpc. This directory can be used to expose some of the specific features that powerpc PMU supports to the user. Example: pmu_name. The name of PMU registered will depend on platform, say power9 or power10 or it could be Generic Compat PMU. Currently the only way to know which is the registered PMU is from the dmesg logs. But clearing the dmesg will make it difficult to know exact PMU backend used. And even extracting from dmesg will be complicated, as we need to parse the dmesg logs and add filters for pmu name. Whereas by exposing it via caps will make it easy as we just need to directly read it from the sysfs. Add a caps directory to /sys/bus/event_source/devices/cpu/ for power8, power9, power10 and generic compat PMU in respective PMU driver code. Update the pmu_name file under caps folder in core-book3s using "attr_update". The information exposed currently: - pmu_name : Underlying PMU name from the driver Example result with power9 pmu: # ls /sys/bus/event_source/devices/cpu/caps pmu_name # cat /sys/bus/event_source/devices/cpu/caps/pmu_name POWER9 Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> --- Changelog: v1 -> v2: Move the show function as generic in core-book3s and update show function using sysfs_emit and ppmu->name Added Documention for this ABI in patch 2. Notes: The caps directory is implemented in PMU for other architectures already. Reference commit for x86: commit b00233b53065 ("perf/x86: Export some PMU attributes in caps/ directory") arch/powerpc/perf/core-book3s.c | 31 ++++++++++++++++++++++++++ arch/powerpc/perf/generic-compat-pmu.c | 10 +++++++++ arch/powerpc/perf/power10-pmu.c | 10 +++++++++ arch/powerpc/perf/power8-pmu.c | 10 +++++++++ arch/powerpc/perf/power9-pmu.c | 10 +++++++++ 5 files changed, 71 insertions(+)