Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 5 Dec 2018 10:58:32 +0800 | From | leo.yan@linaro ... | Subject | Re: [PATCH v1 2/5] perf cs-etm: Avoid stale branch samples when flush packet |
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On Fri, Nov 16, 2018 at 04:05:11PM -0700, Mathieu Poirier wrote:
[...]
> > -static int cs_etm__flush(struct cs_etm_queue *etmq) > > +static int cs_etm__flush(struct cs_etm_queue *etmq, bool new_packet) > > { > > int err = 0; > > struct cs_etm_auxtrace *etm = etmq->etm; > > @@ -989,6 +989,20 @@ static int cs_etm__flush(struct cs_etm_queue *etmq) > > > > } > > > > + /* > > + * If 'new_packet' is false, this time call has no a new packet > > + * coming and 'etmq->packet' contains the stale packet which is > > + * set at the previous time with packets swapping. In this case > > + * this function is invoked only for flushing branch stack at > > + * the end of buffer handling. > > + * > > + * Simply to say, branch samples should be generated when every > > + * time receive one new packet; otherwise, directly bail out to > > + * avoid generate branch sample with stale packet. > > + */ > > + if (!new_packet) > > + return 0; > > + > > if (etm->sample_branches && > > etmq->prev_packet->sample_type == CS_ETM_RANGE) { > > err = cs_etm__synth_branch_sample(etmq); > > @@ -1075,7 +1089,7 @@ static int cs_etm__run_decoder(struct cs_etm_queue *etmq) > > * Discontinuity in trace, flush > > * previous branch stack > > */ > > - cs_etm__flush(etmq); > > + cs_etm__flush(etmq, true); > > break; > > case CS_ETM_EMPTY: > > /* > > @@ -1092,7 +1106,7 @@ static int cs_etm__run_decoder(struct cs_etm_queue *etmq) > > > > if (err == 0) > > /* Flush any remaining branch stack entries */ > > - err = cs_etm__flush(etmq); > > + err = cs_etm__flush(etmq, false); > > I understand what you're doing and it will yield the correct results. What I'm > not sure about is if we wouldn't be better off splitting cs_etm__flush() > in order to reduce the complexity of the main decoding loop. That is rename > cs_etm__flush() to something like cs_etm__trace_on() and spin off a new > cs_etm__end_block(). > > It does introduce a little bit of code duplication but I think we'd win in terms > of readability and flexibility.
Sorry for long delay, Mathieu.
Agree with the idea of splitting cs_etm__flush() into two functions. Will spin patch for new version.
Thanks, Leo Yan
> > } > > > > return err; > > -- > > 2.7.4 > >
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