Messages in this thread Patch in this message | | | Subject | Re: [PATCH v1 2/3] perf session: Add swap operation for event TIME_CONV | From | Adrian Hunter <> | Date | Mon, 26 Apr 2021 08:40:00 +0300 |
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On 12/04/21 11:34 am, Leo Yan wrote: > Since commit d110162cafc8 ("perf tsc: Support cap_user_time_short for > event TIME_CONV"), the event PERF_RECORD_TIME_CONV has extended the data > structure for clock parameters. > > To be backwards-compatible, this patch adds a dedicated swap operation > for the event PERF_RECORD_TIME_CONV, based on checking the event size, > it can support both for the old and new event formats. > > Fixes: d110162cafc8 ("perf tsc: Support cap_user_time_short for event TIME_CONV") > Signed-off-by: Leo Yan <leo.yan@linaro.org> > --- > tools/perf/util/session.c | 22 +++++++++++++++++++++- > 1 file changed, 21 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c > index 9a8808507bd9..afca3d5fc851 100644 > --- a/tools/perf/util/session.c > +++ b/tools/perf/util/session.c > @@ -949,6 +949,26 @@ static void perf_event__stat_round_swap(union perf_event *event, > event->stat_round.time = bswap_64(event->stat_round.time); > } > > +static void perf_event__time_conv_swap(union perf_event *event, > + bool sample_id_all __maybe_unused) > +{ > + size_t time_zero_size; > + > + event->time_conv.time_shift = bswap_64(event->time_conv.time_shift); > + event->time_conv.time_mult = bswap_64(event->time_conv.time_mult); > + event->time_conv.time_zero = bswap_64(event->time_conv.time_zero); > + > + time_zero_size = (void *)&event->time_conv.time_cycles - (void *)event; > + if (event->header.size > time_zero_size) {
I wonder if we could have a helper for this e.g. (untested)
#define event_contains(obj, mem) (obj.header.size > offsetof(typeof(obj), mem))
if (event_contains(event->time_conv, time_cycles)) {
> + event->time_conv.time_cycles = bswap_64(event->time_conv.time_cycles); > + event->time_conv.time_mask = bswap_64(event->time_conv.time_mask); > + event->time_conv.cap_user_time_zero = > + bswap_32(event->time_conv.cap_user_time_zero); > + event->time_conv.cap_user_time_short = > + bswap_32(event->time_conv.cap_user_time_short);
'struct perf_record_time_conv' contains bool, the sizeof which, AFAIK, is not defined. Is it really 4 bytes on your implementation? It is only 1 byte with gcc on x86.
Either way, you should change 'struct perf_record_time_conv' so it uses a type of known size. Since you are the only one using it, it should match your implementation.
> + } > +} > + > typedef void (*perf_event__swap_op)(union perf_event *event, > bool sample_id_all); > > @@ -985,7 +1005,7 @@ static perf_event__swap_op perf_event__swap_ops[] = { > [PERF_RECORD_STAT] = perf_event__stat_swap, > [PERF_RECORD_STAT_ROUND] = perf_event__stat_round_swap, > [PERF_RECORD_EVENT_UPDATE] = perf_event__event_update_swap, > - [PERF_RECORD_TIME_CONV] = perf_event__all64_swap, > + [PERF_RECORD_TIME_CONV] = perf_event__time_conv_swap, > [PERF_RECORD_HEADER_MAX] = NULL, > }; > >
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