Messages in this thread | | | Subject | Re: [PATCH] perf evsel: Fix incorrect precise_ip in default event name | From | zhangmengting <> | Date | Fri, 10 Nov 2017 15:56:17 +0800 |
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Hi Namhyung,
Yeah, you are right. I'll send a new patch later.
Thanks,
Mengting Zhang
On 2017/11/10 14:30, Namhyung Kim wrote: > Hello, > > On Fri, Nov 10, 2017 at 01:49:06PM +0800, Mengting Zhang wrote: >> When no event is specified with -e option, perf will specify a >> "cycles" event with the highest level of precision available in >> perf_event_attr.precise_ip as the default event. But the evsel name >> shows an incorrect precise ip, fix it. >> >> For example, with a highest precision perf_event_attr.precise_ip = 2, >> the evsel name "cycles:ppp" shows a wrong precision available. >> >> Before: >> $./perf record sleep 1 >> [ perf record: Woken up 1 times to write data ] >> [ perf record: Captured and wrote 0.014 MB perf.data (21 samples) ] >> $./perf evlist -v >> cycles:ppp: size: 112, { sample_period, sample_freq }: 4000, >> sample_type: IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, mmap: 1, >> comm: 1, freq: 1, enable_on_exec: 1, task: 1, precise_ip: 2, >> sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1 >> >> After: >> $./perf record sleep 1 >> [ perf record: Woken up 1 times to write data ] >> [ perf record: Captured and wrote 0.014 MB perf.data (16 samples) ] >> $./perf evlist -v >> cycles:pp: size: 112, { sample_period, sample_freq }: 4000, >> sample_type: IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, mmap: 1, >> comm: 1, freq: 1, enable_on_exec: 1, task: 1, precise_ip: 2, >> sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1 >> >> Signed-off-by: Mengting Zhang <zhangmengting@huawei.com> >> --- >> tools/perf/util/evsel.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c >> index 0dccdb8..94cf11d 100644 >> --- a/tools/perf/util/evsel.c >> +++ b/tools/perf/util/evsel.c >> @@ -312,7 +312,7 @@ struct perf_evsel *perf_evsel__new_cycles(bool precise) >> if (asprintf(&evsel->name, "cycles%s%s%.*s", >> (attr.precise_ip || attr.exclude_kernel) ? ":" : "", >> attr.exclude_kernel ? "u" : "", >> - attr.precise_ip ? attr.precise_ip + 1 : 0, "ppp") < 0) >> + attr.precise_ip ? attr.precise_ip : 0, "ppp") < 0) > I think you don't need to check value of the precise_ip anymore. > The following should be ok: > > attr.precise_ip, "ppp") < 0) > > Thanks, > Namhyung > > > . >
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