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From: Mike Leach <mike.leach@linaro.org>
To: linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org,
	linux-kernel@vger.kernel.org, acme@kernel.org
Cc: peterz@infradead.org, mingo@redhat.com,
	Mike Leach <mike.leach@linaro.org>,
	mathieu.poirier@linaro.org, suzuki.poulose@arm.com
Subject: [PATCH v4 0/1] perf: cs_etm: Allow no sink on command line.
Date: Tue, 26 May 2020 11:53:09 +0100	[thread overview]
Message-ID: <20200526105310.9706-1-mike.leach@linaro.org> (raw)

Currently starting CoreSight tracing using perf requires a sink selection
on the command line:-

sudo ./perf record -e cs_etm/@tmc_etr0/ --per-thread uname -a

Not providing the @<sink> here results in an error and no trace produced.

After this set (alongside the CoreSight change set [1]) the infrastructure
will be able to select a default sink:-

sudo ./perf record -e cs_etm// --per-thread uname -a

This matches with the default operation provided with perf and intelpt.

This patch removes the check that a sink value is provided on the command
line with a NULL value passed to the CoreSight infrastructure if omitted.

Note: If this set is applied to a system without [1], then the effect is
benign as the existing CoreSight infrastructure will detect the error and
refuse to trace.

Applies to Linux coresight/next branch

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2020-May/734854.html

Changes since v3:
1) Removed RFC designation and distributed to wider audience.
2) Split set into perf user runtime (this set), and CoreSight driver code.


Mike Leach (1):
  perf: cs-etm: Allow no CoreSight sink to be specified on command line

 tools/perf/arch/arm/util/cs-etm.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

-- 
2.17.1


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             reply	other threads:[~2020-05-26 10:53 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-26 10:53 Mike Leach [this message]
2020-05-26 10:53 ` [PATCH v4 1/1] perf: cs-etm: Allow no CoreSight sink to be specified on command line Mike Leach
2020-06-04 21:21   ` Mathieu Poirier

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