From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751382AbeEVJxF (ORCPT ); Tue, 22 May 2018 05:53:05 -0400 Received: from mail-pg0-f67.google.com ([74.125.83.67]:43132 "EHLO mail-pg0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751060AbeEVJxC (ORCPT ); Tue, 22 May 2018 05:53:02 -0400 X-Google-Smtp-Source: AB8JxZqZsemCDh6sF1HAr1BnWpras/puJiy8co1gGVmZ5efZClBAzo8L7YBUwNeE1K7HXsnkvQOw3w== Date: Tue, 22 May 2018 17:52:49 +0800 From: Leo Yan To: Robert Walker Cc: Arnaldo Carvalho de Melo , Mathieu Poirier , Jonathan Corbet , Peter Zijlstra , Ingo Molnar , Alexander Shishkin , Jiri Olsa , Namhyung Kim , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Tor Jeremiassen , mike.leach@linaro.org, kim.phillips@arm.com, coresight@lists.linaro.org, Mike Leach Subject: Re: [RFT v2 1/4] perf cs-etm: Generate sample for missed packets Message-ID: <20180522095249.GE31075@leoy-ThinkPad-X240s> References: <1526892748-326-1-git-send-email-leo.yan@linaro.org> <1526892748-326-2-git-send-email-leo.yan@linaro.org> <20180522083920.GD31075@leoy-ThinkPad-X240s> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180522083920.GD31075@leoy-ThinkPad-X240s> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 22, 2018 at 04:39:20PM +0800, Leo Yan wrote: [...] Rather than the patch I posted in my previous email, I think below new patch is more reasonable for me. In the below change, 'etmq->prev_packet' is only used to store the previous CS_ETM_RANGE packet, we don't need to save CS_ETM_TRACE_ON packet into 'etmq->prev_packet'. On the other hand, cs_etm__flush() can use 'etmq->period_instructions' to indicate if need to generate instruction sample or not. If it's non-zero, then generate instruction sample and 'etmq->period_instructions' will be cleared; so next time if there have more tracing CS_ETM_TRACE_ON packet, it can skip to generate instruction sample due 'etmq->period_instructions' is zero. How about you think for this? Thanks, Leo Yan diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 822ba91..dd354ad 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -495,6 +495,13 @@ static inline void cs_etm__reset_last_branch_rb(struct cs_etm_queue *etmq) static inline u64 cs_etm__last_executed_instr(struct cs_etm_packet *packet) { /* + * The packet is the start tracing packet if the end_addr is zero, + * returns 0 for this case. + */ + if (!packet->end_addr) + return 0; + + /* * The packet records the execution range with an exclusive end address * * A64 instructions are constant size, so the last executed @@ -897,13 +904,27 @@ static int cs_etm__sample(struct cs_etm_queue *etmq) etmq->period_instructions = instrs_over; } - if (etm->sample_branches && - etmq->prev_packet && - etmq->prev_packet->sample_type == CS_ETM_RANGE && - etmq->prev_packet->last_instr_taken_branch) { - ret = cs_etm__synth_branch_sample(etmq); - if (ret) - return ret; + if (etm->sample_branches && etmq->prev_packet) { + bool generate_sample = false; + + /* Generate sample for start tracing packet */ + if (etmq->prev_packet->sample_type == 0) + generate_sample = true; + + /* Generate sample for exception packet */ + if (etmq->prev_packet->exc == true) + generate_sample = true; + + /* Generate sample for normal branch packet */ + if (etmq->prev_packet->sample_type == CS_ETM_RANGE && + etmq->prev_packet->last_instr_taken_branch) + generate_sample = true; + + if (generate_sample) { + ret = cs_etm__synth_branch_sample(etmq); + if (ret) + return ret; + } } if (etm->sample_branches || etm->synth_opts.last_branch) { @@ -922,11 +943,12 @@ static int cs_etm__sample(struct cs_etm_queue *etmq) static int cs_etm__flush(struct cs_etm_queue *etmq) { int err = 0; - struct cs_etm_packet *tmp; if (etmq->etm->synth_opts.last_branch && etmq->prev_packet && - etmq->prev_packet->sample_type == CS_ETM_RANGE) { + etmq->prev_packet->sample_type == CS_ETM_RANGE && + etmq->period_instructions) { + /* * Generate a last branch event for the branches left in the * circular buffer at the end of the trace. @@ -940,14 +962,6 @@ static int cs_etm__flush(struct cs_etm_queue *etmq) etmq, addr, etmq->period_instructions); etmq->period_instructions = 0; - - /* - * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for - * the next incoming packet. - */ - tmp = etmq->packet; - etmq->packet = etmq->prev_packet; - etmq->prev_packet = tmp; } return err; -- 2.7.4