| Message ID | 20220913115546.36179-1-atrajeev@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | [1/3] powerpc/perf: Fix branch_filter support for multiple filters in powerpc | expand |
On 9/13/22 5:25 PM, Athira Rajeev wrote: > For PERF_SAMPLE_BRANCH_STACK sample type, different branch_sample_type > ie branch filters are supported. The branch filters are requested via > event attribute "branch_sample_type". Multiple branch filters can be > passed in event attribute. > > Example: > perf record -b -o- -B --branch-filter any,ind_call true > > Powerpc does not support having multiple branch filters at > sametime. In powerpc, branch filters for branch stack sampling > is set via MMCRA IFM bits [32:33]. But currently when requesting > for multiple filter types, the "perf record" command does not > report any error. > > Example: > perf record -b -o- -B --branch-filter any,save_type true > perf record -b -o- -B --branch-filter any,ind_call true > > The "bhrb_filter_map" function in PMU driver code does the > validity check for supported branch filters. But this check > is done for single filter. Hence "perf record" will proceed > here without reporting any error. > > Fix power_pmu_event_init to return EOPNOTSUPP when multiple > branch filters are requested in the event attr. > > After the fix: > perf record --branch-filter any,ind_call -- ls > Error: > cycles: PMU Hardware doesn't support sampling/overflow-interrupts. > Try 'perf stat' > > Reported-by: Disha Goel<disgoel@linux.vnet.ibm.com> > Signed-off-by: Athira Rajeev<atrajeev@linux.vnet.ibm.com> > Reviewed-by: Madhavan Srinivasan<maddy@linux.ibm.com> Tested-by: Disha Goel<disgoel@linux.vnet.ibm.com> > --- > arch/powerpc/perf/core-book3s.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c > index 13919eb96931..2c2d235cb8d8 100644 > --- a/arch/powerpc/perf/core-book3s.c > +++ b/arch/powerpc/perf/core-book3s.c > @@ -2131,6 +2131,21 @@ static int power_pmu_event_init(struct perf_event *event) > if (has_branch_stack(event)) { > u64 bhrb_filter = -1; > > + /* > + * powerpc does not support having multiple branch filters > + * at sametime. Branch filters are set via MMCRA IFM[32:33] > + * bits for power8 and above. Return EOPNOTSUPP when multiple > + * branch filters are requested in the event attr. > + * > + * When opening event via perf_event_open, branch_sample_type > + * gets adjusted in perf_copy_attr function. Kernel will > + * automatically adjust the branch_sample_type based on the > + * event modifier settings to include PERF_SAMPLE_BRANCH_PLM_ALL. > + * Hence drop the check for PERF_SAMPLE_BRANCH_PLM_ALL. > + */ > + if (hweight64(event->attr.branch_sample_type & ~PERF_SAMPLE_BRANCH_PLM_ALL) > 1) > + return -EOPNOTSUPP; > + > if (ppmu->bhrb_filter_map) > bhrb_filter = ppmu->bhrb_filter_map( > event->attr.branch_sample_type);
On 9/16/22 17:02, Disha Goel wrote: > > On 9/13/22 5:25 PM, Athira Rajeev wrote: >> For PERF_SAMPLE_BRANCH_STACK sample type, different branch_sample_type >> ie branch filters are supported. The branch filters are requested via >> event attribute "branch_sample_type". Multiple branch filters can be >> passed in event attribute. >> >> Example: >> perf record -b -o- -B --branch-filter any,ind_call true >> >> Powerpc does not support having multiple branch filters at >> sametime. In powerpc, branch filters for branch stack sampling >> is set via MMCRA IFM bits [32:33]. But currently when requesting >> for multiple filter types, the "perf record" command does not >> report any error. >> >> Example: >> perf record -b -o- -B --branch-filter any,save_type true >> perf record -b -o- -B --branch-filter any,ind_call true >> >> The "bhrb_filter_map" function in PMU driver code does the >> validity check for supported branch filters. But this check >> is done for single filter. Hence "perf record" will proceed >> here without reporting any error. >> >> Fix power_pmu_event_init to return EOPNOTSUPP when multiple >> branch filters are requested in the event attr. >> >> After the fix: >> perf record --branch-filter any,ind_call -- ls >> Error: >> cycles: PMU Hardware doesn't support sampling/overflow-interrupts. >> Try 'perf stat' >> >> Reported-by: Disha Goel <disgoel@linux.vnet.ibm.com> >> Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> >> Reviewed-by: Madhavan Srinivasan <maddy@linux.ibm.com> > > Tested-by: Disha Goel <disgoel@linux.vnet.ibm.com> Patch looks good to me. Reviewed-By: Kajol Jain <kjain@linux.ibm.com> Thanks, Kajol Jain > >> --- >> arch/powerpc/perf/core-book3s.c | 15 +++++++++++++++ >> 1 file changed, 15 insertions(+) >> >> diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c >> index 13919eb96931..2c2d235cb8d8 100644 >> --- a/arch/powerpc/perf/core-book3s.c >> +++ b/arch/powerpc/perf/core-book3s.c >> @@ -2131,6 +2131,21 @@ static int power_pmu_event_init(struct perf_event *event) >> if (has_branch_stack(event)) { >> u64 bhrb_filter = -1; >> >> + /* >> + * powerpc does not support having multiple branch filters >> + * at sametime. Branch filters are set via MMCRA IFM[32:33] >> + * bits for power8 and above. Return EOPNOTSUPP when multiple >> + * branch filters are requested in the event attr. >> + * >> + * When opening event via perf_event_open, branch_sample_type >> + * gets adjusted in perf_copy_attr function. Kernel will >> + * automatically adjust the branch_sample_type based on the >> + * event modifier settings to include PERF_SAMPLE_BRANCH_PLM_ALL. >> + * Hence drop the check for PERF_SAMPLE_BRANCH_PLM_ALL. >> + */ >> + if (hweight64(event->attr.branch_sample_type & ~PERF_SAMPLE_BRANCH_PLM_ALL) > 1) >> + return -EOPNOTSUPP; >> + >> if (ppmu->bhrb_filter_map) >> bhrb_filter = ppmu->bhrb_filter_map( >> event->attr.branch_sample_type);
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index 13919eb96931..2c2d235cb8d8 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -2131,6 +2131,21 @@ static int power_pmu_event_init(struct perf_event *event) if (has_branch_stack(event)) { u64 bhrb_filter = -1; + /* + * powerpc does not support having multiple branch filters + * at sametime. Branch filters are set via MMCRA IFM[32:33] + * bits for power8 and above. Return EOPNOTSUPP when multiple + * branch filters are requested in the event attr. + * + * When opening event via perf_event_open, branch_sample_type + * gets adjusted in perf_copy_attr function. Kernel will + * automatically adjust the branch_sample_type based on the + * event modifier settings to include PERF_SAMPLE_BRANCH_PLM_ALL. + * Hence drop the check for PERF_SAMPLE_BRANCH_PLM_ALL. + */ + if (hweight64(event->attr.branch_sample_type & ~PERF_SAMPLE_BRANCH_PLM_ALL) > 1) + return -EOPNOTSUPP; + if (ppmu->bhrb_filter_map) bhrb_filter = ppmu->bhrb_filter_map( event->attr.branch_sample_type);