linux-kernel - Re: [RFC PATCH 5/6] perf cs-etm: Improve Coresight zero timestamp warning

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Message-ID: <YQlD06FZ3SyBeolc@kernel.org>
Date:   Tue, 3 Aug 2021 10:25:39 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Leo Yan <leo.yan@...aro.org>
Cc:     James Clark <james.clark@....com>, mathieu.poirier@...aro.org,
        coresight@...ts.linaro.org, linux-perf-users@...r.kernel.org,
        suzuki.poulose@....com, mike.leach@...aro.org,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        John Garry <john.garry@...wei.com>,
        Will Deacon <will@...nel.org>, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [RFC PATCH 5/6] perf cs-etm: Improve Coresight zero timestamp
 warning

Em Mon, Aug 02, 2021 at 11:17:10PM +0800, Leo Yan escreveu:
> On Thu, Jul 29, 2021 at 04:58:04PM +0100, James Clark wrote:
> > Only show the warning if the user hasn't already set timeless mode and
> > improve the text because there was ambiguity around the meaning of '...'
> > 
> > Change the warning to a UI warning instead of printing straight to
> > stderr because this corrupts the UI when perf report TUI is used. The UI
> > warning function also handles printing to stderr when in perf script
> > mode.
> > 
> > Suggested-by: Leo Yan <leo.yan@...aro.org>
> > Signed-off-by: James Clark <james.clark@....com>
> 
> Reviewed-by: Leo Yan <leo.yan@...aro.org>

Thanks, applied.

- Arnaldo

 
> > ---
> >  tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 7 +++++--
> >  1 file changed, 5 insertions(+), 2 deletions(-)
> > 
> > diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
> > index 3e1a05bc82cc..5084bd2ca6eb 100644
> > --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
> > +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
> > @@ -324,8 +324,11 @@ cs_etm_decoder__do_hard_timestamp(struct cs_etm_queue *etmq,
> >  		 * underflow.
> >  		 */
> >  		packet_queue->cs_timestamp = 0;
> > -		WARN_ONCE(true, "Zero Coresight timestamp found at Idx:%" OCSD_TRC_IDX_STR
> > -				". Decoding may be improved with --itrace=Z...\n", indx);
> > +		if (!cs_etm__etmq_is_timeless(etmq))
> > +			pr_warning_once("Zero Coresight timestamp found at Idx:%" OCSD_TRC_IDX_STR
> > +					". Decoding may be improved by prepending 'Z' to your current --itrace arguments.\n",
> > +					indx);
> > +
> >  	} else if (packet_queue->instr_count > elem->timestamp) {
> >  		/*
> >  		 * Sanity check that the elem->timestamp - packet_queue->instr_count would not
> > -- 
> > 2.28.0
> > 

-- 

- Arnaldo