CoreSight January 2019

coresight@lists.linaro.org

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[PATCH v4 0/8] perf cs-etm: Add support for sample flags

by Leo Yan

This patch seris adds support for sample flags so can facilitate perf to print sample flags for branch instruction. Patch 0001 is used to save last branch information in packet structure, this includes instruction type, subtype and condition flag to help making decision for which branch instruction it is. It passes related information from decoder layer to cs-etm.c, so we use cs-etm.c as a central place to set sample flags. Patch 0002 is used to set sample flags for instruction range packet. Patch 0003 is used to set sample flags for trace discontinuity packet. Patches 0004/0005/0006 are preparation for exception packet handling: Patch 0004 addes exception number in packet; pacth 0005/0006 is to use traceID/metadata pointer tuple to access metadata pointer based on trace ID, so this can help decide if the CPU is connected with ETMv3 or ETMv4, ETMv3 and ETMv4 have totally different definition for exception numbers. Patch 0007 sets sample flags for exception packet; patch 0008 support sample flags for exception return packet. As Mathieu pointed out, one most difficult thing is to handle nest interrupt and trace discontinuity for exception return packet; if we use one data structure to maintain the interrupt context and also track the nest interrupts, this will be complex. So in patch 0008 we simply to check if there have one SVC instruction prior to the return address, by this way we can simply get rid of the dependency between the exception packet and exception return packet for setting sample flags, thus this can let us to set sample flags for exception return packet only based on the sequential instruction range packet. This patch series is applied on the acme's perf core branch [1] with the with latest commit ee412f14693a ("tools include uapi: Sync linux/vhost.h with the kernel sources"). After applying the dependency patches and this patch series, we can verify sample flags with below command: # perf script -F,-time,+flags,+ip,+sym,+dso,+addr,+symoff -k vmlinux Changes from v3: * Fixed typos in commit logs; * Rearranged fields in cs_etm_packet by grouping with same variable types; * Fixed ETMv4 exception number which pointed by Mike; * Fixed ETMv4 SVC / SMC / HVC in the same CALL, by checking svc instruction to distinguish them; * Refine ETMv4 return exception packet handling. Changes from v2: * Addressed Mathieu's suggestion to split one big patch to 3 small patches for setting sample flags, one is for instruction range packet, one is for discontinuity packet and one is for exception packet. * Added supporting for ETMv3 exception packet. * Followed Mathieu's suggestion to move all sample flags handling from decoder layer to cs-etm.c, thus it has enough info to set flags based on trace context in single place. Changes from v1: * Moved exception packets handling patches into patch series 'perf cs-etm: Correct packets handling'. * Added sample flags fixing up for TRACE_OFF packet. * Created a new function which is used to maintain flags fixing up. [1] https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git/log/?h=perf/… Leo Yan (8): perf cs-etm: Add last instruction information in packet perf cs-etm: Set sample flags for instruction range packet perf cs-etm: Set sample flags for trace discontinuity perf cs-etm: Add exception number in exception packet perf cs-etm: Change tuple from traceID-CPU# to traceID-metadata perf cs-etm: Add traceID in packet perf cs-etm: Set sample flags for exception packet perf cs-etm: Set sample flags for exception return packet .../perf/util/cs-etm-decoder/cs-etm-decoder.c | 36 +- .../perf/util/cs-etm-decoder/cs-etm-decoder.h | 6 + tools/perf/util/cs-etm.c | 383 +++++++++++++++++- tools/perf/util/cs-etm.h | 43 +- 4 files changed, 454 insertions(+), 14 deletions(-) -- 2.17.1

5 years, 3 months

[PATCH AUTOSEL 4.19 77/97] perf cs-etm: Correct packets swapping in cs_etm__flush()

by Sasha Levin

From: Leo Yan <leo.yan(a)linaro.org> [ Upstream commit 43fd56669c28cd354e9228bdb58e4bca1c1a8b66 ] The structure cs_etm_queue uses 'prev_packet' to point to previous packet, this can be used to combine with new coming packet to generate samples. In function cs_etm__flush() it swaps packets only when the flag 'etm->synth_opts.last_branch' is true, this means that it will not swap packets if without option '--itrace=il' to generate last branch entries; thus for this case the 'prev_packet' doesn't point to the correct previous packet and the stale packet still will be used to generate sequential sample. Thus if dump trace with 'perf script' command we can see the incorrect flow with the stale packet's address info. This patch corrects packets swapping in cs_etm__flush(); except using the flag 'etm->synth_opts.last_branch' it also checks the another flag 'etm->sample_branches', if any flag is true then it swaps packets so can save correct content to 'prev_packet'. Finally this can fix the wrong program flow dumping issue. The patch has a minor refactoring to use 'etm->synth_opts.last_branch' instead of 'etmq->etm->synth_opts.last_branch' for condition checking, this is consistent with that is done in cs_etm__sample(). Signed-off-by: Leo Yan <leo.yan(a)linaro.org> Reviewed-by: Mathieu Poirier <mathieu.poirier(a)linaro.org> Cc: Alexander Shishkin <alexander.shishkin(a)linux.intel.com> Cc: Jiri Olsa <jolsa(a)redhat.com> Cc: Mike Leach <mike.leach(a)linaro.org> Cc: Namhyung Kim <namhyung(a)kernel.org> Cc: Robert Walker <robert.walker(a)arm.com> Cc: coresight(a)lists.linaro.org Cc: linux-arm-kernel(a)lists.infradead.org Link: http://lkml.kernel.org/r/1544513908-16805-2-git-send-email-leo.yan@linaro.o… Signed-off-by: Arnaldo Carvalho de Melo <acme(a)redhat.com> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/perf/util/cs-etm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index ca577658e890..7b5e15cc6b71 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -1005,7 +1005,7 @@ static int cs_etm__flush(struct cs_etm_queue *etmq) } swap_packet: - if (etmq->etm->synth_opts.last_branch) { + if (etm->sample_branches || etm->synth_opts.last_branch) { /* * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for * the next incoming packet. -- 2.19.1

5 years, 3 months

[PATCH AUTOSEL 4.20 093/117] perf cs-etm: Correct packets swapping in cs_etm__flush()

by Sasha Levin

From: Leo Yan <leo.yan(a)linaro.org> [ Upstream commit 43fd56669c28cd354e9228bdb58e4bca1c1a8b66 ] The structure cs_etm_queue uses 'prev_packet' to point to previous packet, this can be used to combine with new coming packet to generate samples. In function cs_etm__flush() it swaps packets only when the flag 'etm->synth_opts.last_branch' is true, this means that it will not swap packets if without option '--itrace=il' to generate last branch entries; thus for this case the 'prev_packet' doesn't point to the correct previous packet and the stale packet still will be used to generate sequential sample. Thus if dump trace with 'perf script' command we can see the incorrect flow with the stale packet's address info. This patch corrects packets swapping in cs_etm__flush(); except using the flag 'etm->synth_opts.last_branch' it also checks the another flag 'etm->sample_branches', if any flag is true then it swaps packets so can save correct content to 'prev_packet'. Finally this can fix the wrong program flow dumping issue. The patch has a minor refactoring to use 'etm->synth_opts.last_branch' instead of 'etmq->etm->synth_opts.last_branch' for condition checking, this is consistent with that is done in cs_etm__sample(). Signed-off-by: Leo Yan <leo.yan(a)linaro.org> Reviewed-by: Mathieu Poirier <mathieu.poirier(a)linaro.org> Cc: Alexander Shishkin <alexander.shishkin(a)linux.intel.com> Cc: Jiri Olsa <jolsa(a)redhat.com> Cc: Mike Leach <mike.leach(a)linaro.org> Cc: Namhyung Kim <namhyung(a)kernel.org> Cc: Robert Walker <robert.walker(a)arm.com> Cc: coresight(a)lists.linaro.org Cc: linux-arm-kernel(a)lists.infradead.org Link: http://lkml.kernel.org/r/1544513908-16805-2-git-send-email-leo.yan@linaro.o… Signed-off-by: Arnaldo Carvalho de Melo <acme(a)redhat.com> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/perf/util/cs-etm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 73430b73570d..c2f0c92623f0 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -1005,7 +1005,7 @@ static int cs_etm__flush(struct cs_etm_queue *etmq) } swap_packet: - if (etmq->etm->synth_opts.last_branch) { + if (etm->sample_branches || etm->synth_opts.last_branch) { /* * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for * the next incoming packet. -- 2.19.1

5 years, 3 months

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CoreSight January 2019