Messages in this thread | | | Date | Fri, 10 Nov 2017 11:39:00 +0100 | From | Jiri Olsa <> | Subject | Re: [PATCH] perf parse events: Fix invalid precise_ip handling |
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On Fri, Nov 10, 2017 at 04:28:37PM +0800, Mengting Zhang wrote:
SNIP
> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c > index 39b1596..25225f4 100644 > --- a/tools/perf/util/parse-events.c > +++ b/tools/perf/util/parse-events.c > @@ -1369,6 +1369,32 @@ struct event_modifier { > int pinned; > }; > > +static int perf_get_max_precise_ip(void) > +{ > + int max_precise_ip = 0; > + struct perf_event_attr attr = { > + .type = PERF_TYPE_HARDWARE, > + .config = PERF_COUNT_HW_CPU_CYCLES, > + }; > + > + event_attr_init(&attr); > + > + attr.precise_ip = 3; > + attr.sample_period = 1; > + > + while (attr.precise_ip != 0) { > + int fd = sys_perf_event_open(&attr, 0, -1, -1, 0); > + if (fd != -1){ > + close(fd); > + break; > + } > + --attr.precise_ip; > + } > + max_precise_ip = attr.precise_ip; > + > + return max_precise_ip; > +}
we already have a function for that, please check perf_event_attr__set_max_precise_ip
also I think the precise level is not generic for all the events, so you should check it for specific perf_event_attr later, when the attr is ready, not in modifier parsing
thanks, jirka
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