On 06/06/2013 10:26 AM, Michael Neuling wrote: > 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?!!?!?!?
Always compile with the cross compiler "ARCH=powerpc CROSS_COMPILE=powerpc64-linux-gnu- make" I copied over arch/powerpc/config/pseries_defconfig and compiled it. Some how it missed to be a 64 bit kernel config which resulted in shutting down compilation of arch/powerpc/perf/power8-pmu.c file. So never encountered this compiler warning message before. Will fix this. Regards Anshuman _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
