From: James Clark <james.clark@arm.com>
To: Leo Yan <leo.yan@linaro.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Mathieu Poirier <mathieu.poirier@linaro.org>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Mike Leach <mike.leach@linaro.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
John Garry <john.garry@huawei.com>, Will Deacon <will@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Jiri Olsa <jolsa@redhat.com>,
Namhyung Kim <namhyung@kernel.org>,
Daniel Kiss <daniel.kiss@arm.com>,
Denis Nikitin <denik@google.com>,
coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org
Subject: Re: [PATCH v1 3/3] perf cs-etm: Remove callback cs_etm_find_snapshot()
Date: Tue, 22 Jun 2021 15:29:35 +0100 [thread overview]
Message-ID: <05442998-05f6-c41c-5a78-3f6723558825@arm.com> (raw)
In-Reply-To: <20210528161552.654907-4-leo.yan@linaro.org>
On 28/05/2021 17:15, Leo Yan wrote:
> The callback cs_etm_find_snapshot() is invoked for snapshot mode, its
> main purpose is to find the correct AUX trace data and returns "head"
> and "old" (we can call "old" as "old head") to the caller, the caller
> __auxtrace_mmap__read() uses these two pointers to decide the AUX trace
> data size.
>
> cs_etm_find_snapshot() should be removed with below reasons:
Hi Leo,
I came across this other comment in coresight-tmc-etr.c that should probably
be fixed up if we remove cs_etm_find_snapshot(). The same is duplicated in a
few other files:
/*
* In snapshot mode we simply increment the head by the number of byte
* that were written. User space function cs_etm_find_snapshot() will
* figure out how many bytes to get from the AUX buffer based on the
* position of the head.
*/
if (etr_perf->snapshot)
handle->head += size;
I'm still reviewing patch 1 and 2 as well.
James
next prev parent reply other threads:[~2021-06-22 14:29 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-28 16:15 [PATCH v1 0/3] coresight: Fix for snapshot mode Leo Yan
2021-05-28 16:15 ` [PATCH v1 1/3] coresight: etm-perf: Correct buffer syncing for snapshot Leo Yan
2021-06-01 9:53 ` James Clark
2021-06-01 10:35 ` Leo Yan
2021-06-10 14:54 ` James Clark
2021-06-11 13:55 ` James Clark
2021-06-08 21:41 ` Mathieu Poirier
2021-06-09 1:35 ` Leo Yan
2021-06-09 1:39 ` Leo Yan
2021-05-28 16:15 ` [PATCH v1 2/3] coresight: tmc-etr: Use perf_output_handle::head for AUX ring buffer Leo Yan
2021-06-10 15:38 ` Suzuki K Poulose
2021-05-28 16:15 ` [PATCH v1 3/3] perf cs-etm: Remove callback cs_etm_find_snapshot() Leo Yan
2021-06-22 14:29 ` James Clark [this message]
2021-06-28 1:31 ` Leo Yan
2021-06-24 16:46 ` James Clark
2021-06-10 6:43 ` [PATCH v1 0/3] coresight: Fix for snapshot mode Denis Nikitin
2021-06-10 16:04 ` Suzuki K Poulose
2021-06-11 8:31 ` Denis Nikitin
2021-06-12 3:27 ` Leo Yan
2021-06-21 8:21 ` Denis Nikitin
2021-06-22 12:58 ` Leo Yan
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