Anshuman Khandual <khand...@linux.vnet.ibm.com> wrote: > Completely ignore BHRB privilege state filter request as we are > already configuring that with privilege state filtering attribute > for the accompanying PMU event. This would help achieve cleaner > user space interaction for BHRB. > > This patch fixes a situation like this > > Before patch:- > ------------ > ./perf record -j any -e branch-misses:k ls > Error: > The sys_perf_event_open() syscall returned with 95 (Operation not supported) > for event (branch-misses:k). > /bin/dmesg may provide additional information. > No CONFIG_PERF_EVENTS=y kernel support configured? > > Here 'perf record' actually copies over ':k' filter request into BHRB > privilege state filter config and our previous check in kernel would > fail that. > > After patch:- > ------------- > ./perf record -j any -e branch-misses:k ls > perf perf.data perf.data.old test-mmap-ring > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.002 MB perf.data (~102 samples) ] > > Signed-off-by: Anshuman Khandual <khand...@linux.vnet.ibm.com> > --- > arch/powerpc/perf/power8-pmu.c | 12 ++++-------- > 1 file changed, 4 insertions(+), 8 deletions(-) > > diff --git a/arch/powerpc/perf/power8-pmu.c b/arch/powerpc/perf/power8-pmu.c > index f7d1c4f..3a58416 100644 > --- a/arch/powerpc/perf/power8-pmu.c > +++ b/arch/powerpc/perf/power8-pmu.c > @@ -525,16 +525,12 @@ static u64 power8_bhrb_filter_map(u64 > branch_sample_type) > u64 pmu_bhrb_filter = 0; > u64 br_privilege = branch_sample_type & ONLY_PLM; > > - /* BHRB and regular PMU events share the same prvillege state > + /* BHRB and regular PMU events share the same privilege state > * filter configuration. BHRB is always recorded along with a > - * regular PMU event. So privilege state filter criteria for BHRB > - * and the companion PMU events has to be the same. As a default > - * "perf record" tool sets all privillege bits ON when no filter > - * criteria is provided in the command line. So as along as all > - * privillege bits are ON or they are OFF, we are good to go. > + * regular PMU event. As the privilege state filter is handled > + * in the basic PMC configuration of the accompanying regular > + * PMU event, we ignore any separate BHRB specific request. > */ > - if ((br_privilege != 7) && (br_privilege != 0)) > - return -1;
br_privilege is now unused which causes this compile error. arch/powerpc/perf/power8-pmu.c:526:6: error: unused variable ‘br_privilege’ [-Werror=unused-variable] I assume since you didn't compile test this code, you also didn't runtime test it either?!!?!?!? Mikey > > /* No branch filter requested */ > if (branch_sample_type & PERF_SAMPLE_BRANCH_ANY) > -- > 1.7.11.7 > > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/linuxppc-dev > _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
