Messages in this thread Patch in this message | | | Date | Thu, 16 Feb 2012 16:55:10 -0800 | From | Greg KH <> | Subject | [01/15] perf evsel: Fix an issue where perf report fails to show the proper percentage |
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3.0-stable review patch. If anyone has any objections, please let me know.
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From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
commit a4a03fc7ef89020baca4f19174e6a43767c6d78a upstream.
This patch fixes an issue where perf report shows nan% for certain perf.data files. The below is from a report for a do_fork probe:
-nan% sshd [kernel.kallsyms] [k] do_fork -nan% packagekitd [kernel.kallsyms] [k] do_fork -nan% dbus-daemon [kernel.kallsyms] [k] do_fork -nan% bash [kernel.kallsyms] [k] do_fork
A git bisect shows commit f3bda2c as the cause. However, looking back through the git history, I saw commit 640c03c which seems to have removed the required initialization for perf_sample->period. The problem only started showing after commit f3bda2c. The below patch re-introduces the initialization and it fixes the problem for me.
With the below patch, for the same perf.data:
73.08% bash [kernel.kallsyms] [k] do_fork 8.97% 11-dhclient [kernel.kallsyms] [k] do_fork 6.41% sshd [kernel.kallsyms] [k] do_fork 3.85% 20-chrony [kernel.kallsyms] [k] do_fork 2.56% sendmail [kernel.kallsyms] [k] do_fork
This patch applies over current linux-tip commit 9949284.
Problem introduced in:
$ git describe 640c03c v2.6.37-rc3-83-g640c03c
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Robert Richter <robert.richter@amd.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/20120203170113.5190.25558.stgit@localhost6.localdomain6 Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- tools/perf/util/evsel.c | 1 + 1 file changed, 1 insertion(+)
--- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -348,6 +348,7 @@ int perf_event__parse_sample(const union data->cpu = data->pid = data->tid = -1; data->stream_id = data->id = data->time = -1ULL; + data->period = 1; if (event->header.type != PERF_RECORD_SAMPLE) { if (!sample_id_all)
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