From f57b05ed532ccf3b3e22878a5678ca10de50ad29 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Wed, 1 Jun 2011 21:43:46 +0200 Subject: perf report: Use properly build_id kernel binaries If we bring the recorded perf data together with kernel binary from another machine using: on server A: perf archive on server B: tar xjvf perf.data.tar.bz2 -C ~/.debug the build_id kernel dso is not properly recognized during the "perf report" command on server B. The reason is, that build_id dsos are added during the session initialization, while the kernel maps are created during the sample event processing. The machine__create_kernel_maps functions ends up creating new dso object for kernel, but it does not check if we already have one added by build_id processing. Also the build_id reading ABI quirk added in commit: - commit b25114817a73bbd2b84ce9dba02ee1ef8989a947 perf build-id: Add quirk to deal with perf.data file format breakage populates the "struct build_id_event::pid" with 0, which is later interpreted as DEFAULT_GUEST_KERNEL_ID. This is not always correct, so it's better to guess the pid value based on the "struct build_id_event::header::misc" value. - Tested with data generated on x86 kernel version v2.6.34 and reported back on x86_64 current kernel. - Not tested for guest kernel case. Note the problem stays for PERF_RECORD_MMAP events recorded by perf that does not use proper pid (HOST_KERNEL_ID/DEFAULT_GUEST_KERNEL_ID). They are misinterpreted within the current perf code. Probably there's not much we can do about that. Cc: Avi Kivity Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Yanmin Zhang Link: http://lkml.kernel.org/r/20110601194346.GB1934@jolsa.brq.redhat.com Signed-off-by: Jiri Olsa Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/header.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'tools/perf/util/header.c') diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index d4f3101773d..b6c1ad123ca 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -726,7 +726,16 @@ static int perf_header__read_build_ids_abi_quirk(struct perf_header *header, return -1; bev.header = old_bev.header; - bev.pid = 0; + + /* + * As the pid is the missing value, we need to fill + * it properly. The header.misc value give us nice hint. + */ + bev.pid = HOST_KERNEL_ID; + if (bev.header.misc == PERF_RECORD_MISC_GUEST_USER || + bev.header.misc == PERF_RECORD_MISC_GUEST_KERNEL) + bev.pid = DEFAULT_GUEST_KERNEL_ID; + memcpy(bev.build_id, old_bev.build_id, sizeof(bev.build_id)); __event_process_build_id(&bev, filename, session); -- cgit v1.2.3