From: Leo Yan <leo.yan@linaro.org> To: James Clark <james.clark@arm.com> Cc: coresight@lists.linaro.org, mathieu.poirier@linaro.org, al.grant@arm.com, branislav.rankov@arm.com, denik@chromium.org, suzuki.poulose@arm.com, anshuman.khandual@arm.com, Mike Leach <mike.leach@linaro.org>, Mark Rutland <mark.rutland@arm.com>, Alexander Shishkin <alexander.shishkin@linux.intel.com>, Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>, John Garry <john.garry@huawei.com>, Will Deacon <will@kernel.org>, linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] perf cs-etm: Handle valid-but-zero timestamps Date: Wed, 12 May 2021 10:08:26 +0800 [thread overview] Message-ID: <20210512020826.GC249068@leoy-ThinkPad-X240s> (raw) In-Reply-To: <da07f930-ccd7-2b46-7b0f-0e9da3bf9482@arm.com> On Tue, May 11, 2021 at 04:53:35PM +0300, James Clark wrote: [...] > /* First get the packet queue for this traceID */ > packet_queue = cs_etm__etmq_get_packet_queue(etmq, trace_chan_id); > @@ -320,7 +323,20 @@ cs_etm_decoder__do_hard_timestamp(struct cs_etm_queue *etmq, > * which instructions started by subtracting the number of instructions > * executed to the timestamp. > */ > - packet_queue->timestamp = elem->timestamp - packet_queue->instr_count; > + if (!elem->timestamp) { > + packet_queue->timestamp = 0; > + if (!warned_timestamp_zero) { > + pr_err("Zero Coresight timestamp found at Idx:%" OCSD_TRC_IDX_STR > + ". Decoding may be improved with --itrace=Z...\n", indx); > + warned_timestamp_zero = true; > + } > + } > + else if (packet_queue->instr_count >= elem->timestamp) { Nitpick: I personally think should use the condition ">" rather than ">=". > + packet_queue->timestamp = 0; > + pr_err("Timestamp calculation underflow at Idx:%" OCSD_TRC_IDX_STR "\n", indx); > + } > + else > + packet_queue->timestamp = elem->timestamp - packet_queue->instr_count; Nitpick for coding style, as described in Documentation/process/coding-style.rst, section "3) Placing Braces and Spaces", so here should use braces with the format: if (!elem->timestamp) { /* print warning */ } else if {packet_queue->instr_count >= elem->timestamp) { /* print warning */ } else { packet_queue->timestamp = elem->timestamp - packet_queue->instr_count; } Thanks, Leo > packet_queue->next_timestamp = elem->timestamp; > packet_queue->instr_count = 0; > > @@ -542,7 +558,7 @@ cs_etm_decoder__set_tid(struct cs_etm_queue *etmq, > > static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer( > const void *context, > - const ocsd_trc_index_t indx __maybe_unused, > + const ocsd_trc_index_t indx, > const u8 trace_chan_id __maybe_unused, > const ocsd_generic_trace_elem *elem) > { > @@ -579,7 +595,8 @@ static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer( > break; > case OCSD_GEN_TRC_ELEM_TIMESTAMP: > resp = cs_etm_decoder__do_hard_timestamp(etmq, elem, > - trace_chan_id); > + trace_chan_id, > + indx); > break; > case OCSD_GEN_TRC_ELEM_PE_CONTEXT: > resp = cs_etm_decoder__set_tid(etmq, packet_queue, > > > James > > > > > Thanks, > > Leo > >
WARNING: multiple messages have this Message-ID (diff)
From: Leo Yan <leo.yan@linaro.org> To: James Clark <james.clark@arm.com> Cc: coresight@lists.linaro.org, mathieu.poirier@linaro.org, al.grant@arm.com, branislav.rankov@arm.com, denik@chromium.org, suzuki.poulose@arm.com, anshuman.khandual@arm.com, Mike Leach <mike.leach@linaro.org>, Mark Rutland <mark.rutland@arm.com>, Alexander Shishkin <alexander.shishkin@linux.intel.com>, Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>, John Garry <john.garry@huawei.com>, Will Deacon <will@kernel.org>, linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] perf cs-etm: Handle valid-but-zero timestamps Date: Wed, 12 May 2021 10:08:26 +0800 [thread overview] Message-ID: <20210512020826.GC249068@leoy-ThinkPad-X240s> (raw) In-Reply-To: <da07f930-ccd7-2b46-7b0f-0e9da3bf9482@arm.com> On Tue, May 11, 2021 at 04:53:35PM +0300, James Clark wrote: [...] > /* First get the packet queue for this traceID */ > packet_queue = cs_etm__etmq_get_packet_queue(etmq, trace_chan_id); > @@ -320,7 +323,20 @@ cs_etm_decoder__do_hard_timestamp(struct cs_etm_queue *etmq, > * which instructions started by subtracting the number of instructions > * executed to the timestamp. > */ > - packet_queue->timestamp = elem->timestamp - packet_queue->instr_count; > + if (!elem->timestamp) { > + packet_queue->timestamp = 0; > + if (!warned_timestamp_zero) { > + pr_err("Zero Coresight timestamp found at Idx:%" OCSD_TRC_IDX_STR > + ". Decoding may be improved with --itrace=Z...\n", indx); > + warned_timestamp_zero = true; > + } > + } > + else if (packet_queue->instr_count >= elem->timestamp) { Nitpick: I personally think should use the condition ">" rather than ">=". > + packet_queue->timestamp = 0; > + pr_err("Timestamp calculation underflow at Idx:%" OCSD_TRC_IDX_STR "\n", indx); > + } > + else > + packet_queue->timestamp = elem->timestamp - packet_queue->instr_count; Nitpick for coding style, as described in Documentation/process/coding-style.rst, section "3) Placing Braces and Spaces", so here should use braces with the format: if (!elem->timestamp) { /* print warning */ } else if {packet_queue->instr_count >= elem->timestamp) { /* print warning */ } else { packet_queue->timestamp = elem->timestamp - packet_queue->instr_count; } Thanks, Leo > packet_queue->next_timestamp = elem->timestamp; > packet_queue->instr_count = 0; > > @@ -542,7 +558,7 @@ cs_etm_decoder__set_tid(struct cs_etm_queue *etmq, > > static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer( > const void *context, > - const ocsd_trc_index_t indx __maybe_unused, > + const ocsd_trc_index_t indx, > const u8 trace_chan_id __maybe_unused, > const ocsd_generic_trace_elem *elem) > { > @@ -579,7 +595,8 @@ static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer( > break; > case OCSD_GEN_TRC_ELEM_TIMESTAMP: > resp = cs_etm_decoder__do_hard_timestamp(etmq, elem, > - trace_chan_id); > + trace_chan_id, > + indx); > break; > case OCSD_GEN_TRC_ELEM_PE_CONTEXT: > resp = cs_etm_decoder__set_tid(etmq, packet_queue, > > > James > > > > > Thanks, > > Leo > > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-05-12 2:08 UTC|newest] Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-07 9:58 [RFC PATCH] perf cs-etm: Handle valid-but-zero timestamps James Clark 2021-05-07 9:58 ` James Clark [not found] ` <3926c523-3fdb-66de-8b9c-b68290a5053e@arm.com> 2021-05-07 14:09 ` Mike Leach 2021-05-07 14:09 ` Mike Leach 2021-05-11 7:39 ` Denis Nikitin 2021-05-11 7:39 ` Denis Nikitin 2021-05-11 10:07 ` James Clark 2021-05-11 10:07 ` James Clark 2021-05-10 5:39 ` Leo Yan 2021-05-10 5:39 ` Leo Yan 2021-05-11 8:05 ` Leo Yan 2021-05-11 8:05 ` Leo Yan 2021-05-11 10:00 ` James Clark 2021-05-11 10:00 ` James Clark 2021-05-11 8:06 ` Denis Nikitin 2021-05-11 8:06 ` Denis Nikitin 2021-05-11 8:26 ` Leo Yan 2021-05-11 8:26 ` Leo Yan 2021-05-11 13:53 ` James Clark 2021-05-11 13:53 ` James Clark 2021-05-12 1:20 ` Leo Yan 2021-05-12 1:20 ` Leo Yan 2021-05-13 13:57 ` James Clark 2021-05-13 13:57 ` James Clark 2021-05-12 2:08 ` Leo Yan [this message] 2021-05-12 2:08 ` Leo Yan 2021-05-13 13:10 ` James Clark 2021-05-13 13:10 ` James Clark
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