From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from localhost.localdomain (localhost [127.0.0.1]) by ozlabs.org (Postfix) with ESMTP id B7B272C008E for ; Fri, 7 Jun 2013 09:46:54 +1000 (EST) From: Michael Neuling To: Anshuman Khandual Subject: Re: [PATCH V2 1/2] powerpc, perf: Ignore separate BHRB privilege state filter request In-reply-to: <51B0266F.3090708@linux.vnet.ibm.com> References: <1369716452-28689-1-git-send-email-khandual@linux.vnet.ibm.com> <1369716452-28689-2-git-send-email-khandual@linux.vnet.ibm.com> <20699.1370494560@ale.ozlabs.ibm.com> <51B0266F.3090708@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Date: Fri, 07 Jun 2013 09:46:54 +1000 Message-ID: <31747.1370562414@ale.ozlabs.ibm.com> Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Anshuman Khandual wrote: > On 06/06/2013 10:26 AM, Michael Neuling wrote: > > Anshuman Khandual wrote: > >=20 > >> 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 supp= orted) for event (branch-misses:k). > >> /bin/dmesg may provide additional information. > >> No CONFIG_PERF_EVENTS=3Dy 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 > >> --- > >> 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_sam= ple_type) > >> u64 pmu_bhrb_filter =3D 0; > >> u64 br_privilege =3D branch_sample_type & ONLY_PLM; > >>=20=20 > >> - /* 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 !=3D 7) && (br_privilege !=3D 0)) > >> - return -1; > >=20 > > br_privilege is now unused which causes this compile error. > >=20 > > arch/powerpc/perf/power8-pmu.c:526:6: error: unused variable =E2=80=98b= r_privilege=E2=80=99 [-Werror=3Dunused-variable] > >=20 > > I assume since you didn't compile test this code, you also didn't > > runtime test it either?!!?!?!? >=20 >=20 > Always compile with the cross compiler "ARCH=3Dpowerpc > CROSS_COMPILE=3Dpowerpc64-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. I don't understand this at all... pseries_defconfig is a 64bit kernel. BTW. you don't need to copy it. Just do "make pseries_defconfig && make vmlinux". Mikey