Messages in this thread | | | From | Ian Rogers <> | Date | Wed, 18 May 2022 21:42:39 -0700 | Subject | Re: [PATCH V2 1/2] powerpc/perf: Add support for caps under sysfs in powerpc |
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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 >
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