From: Leo Yan <leo.yan@arm.com>
To: James Clark <james.clark@linaro.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>,
coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Mike Leach <mike.leach@linaro.org>,
Yeoreum Yun <yeoreum.yun@arm.com>, Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Tamas Petz <tamas.petz@arm.com>,
Tamas Zsoldos <tamas.zsoldos@arm.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>
Subject: Re: [PATCH 08/19] coresight: trbe: Use PERF_AUX_FLAG_PARTIAL instead of PERF_AUX_FLAG_COLLISION
Date: Wed, 10 Dec 2025 16:19:58 +0000 [thread overview]
Message-ID: <20251210161958.GA724103@e132581.arm.com> (raw)
In-Reply-To: <f1ac7190-bdd9-4725-8955-d82d6f1912fb@linaro.org>
On Tue, Dec 09, 2025 at 01:40:35PM +0000, James Clark wrote:
[...]
> > > if (!is_trbe_running(trbsr))
> > > - perf_aux_output_flag(handle, PERF_AUX_FLAG_COLLISION);
> > > + perf_aux_output_flag(handle, PERF_AUX_FLAG_PARTIAL);
> >
> > This is interesting. So there is a no possibility for the records to be
> > overridden in the perf ring buffer and incomplete record is all that can
> > happen when TRBE is stopped, without stopping the ETE first ? Could both
> > of these scenarios might be possible as well ?
> >
>
> There's no chance of overwriting because that would be the TRUNCATED case
> and the event would get disabled. PARTIAL seems to be when there was an
> error that's recoverable in the driver only, but as in my other comment I
> don't think the extra complexity is necessary and always using TRUNCATED
> would be enough.
If I extend a bit, I would say that the TRUNCATED flag is used to prevent
buffer overwrites, while the other flags indicate why a record is
incomplete.
Thanks,
Leo
next prev parent reply other threads:[~2025-12-10 16:20 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-01 11:21 [PATCH 00/19] coresight: trbe: Support trigger and circle buffer modes Leo Yan
2025-12-01 11:21 ` [PATCH 01/19] coresight: trbe: Use helpers for checking errata Leo Yan
2025-12-04 12:08 ` Anshuman Khandual
2025-12-01 11:21 ` [PATCH 02/19] coresight: trbe: Remove redundant disable operation Leo Yan
2025-12-04 12:25 ` Anshuman Khandual
2025-12-01 11:21 ` [PATCH 03/19] coresight: trbe: Remove buffer disabling in trbe_handle_overflow() Leo Yan
2025-12-04 12:31 ` Anshuman Khandual
2025-12-01 11:21 ` [PATCH 04/19] coresight: trbe: Remove set_trbe_disabled() from the enable flow Leo Yan
2025-12-04 12:43 ` Anshuman Khandual
2025-12-04 13:25 ` Leo Yan
2025-12-01 11:21 ` [PATCH 05/19] coresight: trbe: Refactor status clearing Leo Yan
2025-12-04 12:57 ` Anshuman Khandual
2025-12-09 15:29 ` Leo Yan
2025-12-01 11:21 ` [PATCH 06/19] coresight: trbe: Refactor syndrome decoding Leo Yan
2025-12-02 11:06 ` Suzuki K Poulose
2025-12-02 14:24 ` Leo Yan
2025-12-09 13:17 ` James Clark
2025-12-09 16:06 ` Leo Yan
2025-12-05 4:10 ` Anshuman Khandual
2025-12-09 15:57 ` Leo Yan
2025-12-01 11:21 ` [PATCH 07/19] coresight: trbe: Refactor AUX flag setting Leo Yan
2025-12-02 11:15 ` Suzuki K Poulose
2025-12-02 14:21 ` Leo Yan
2025-12-09 13:37 ` James Clark
2025-12-10 15:43 ` Leo Yan
2025-12-12 14:50 ` James Clark
2025-12-12 15:27 ` Leo Yan
2025-12-12 15:52 ` James Clark
2025-12-01 11:21 ` [PATCH 08/19] coresight: trbe: Use PERF_AUX_FLAG_PARTIAL instead of PERF_AUX_FLAG_COLLISION Leo Yan
2025-12-05 4:28 ` Anshuman Khandual
2025-12-09 13:40 ` James Clark
2025-12-10 16:19 ` Leo Yan [this message]
2025-12-01 11:21 ` [PATCH 09/19] coresight: trbe: Add fault action argument to trbe_handle_overflow() Leo Yan
2025-12-01 11:22 ` [PATCH 10/19] coresight: trbe: Always check fault action when updating buffer Leo Yan
2025-12-02 12:00 ` Suzuki K Poulose
2025-12-01 11:22 ` [PATCH 11/19] coresight: trbe: Apply overwrite erratum for only wrap event Leo Yan
2025-12-02 12:05 ` Suzuki K Poulose
2025-12-02 16:56 ` Leo Yan
2025-12-02 17:12 ` Leo Yan
2025-12-01 11:22 ` [PATCH 12/19] coresight: trbe: Calculate size for buffer wrapping Leo Yan
2025-12-01 11:22 ` [PATCH 13/19] coresight: trbe: Remove misleading comment Leo Yan
2025-12-01 11:22 ` [PATCH 14/19] coresight: trbe: Refactor compute_trbe_buffer_limit() Leo Yan
2025-12-01 11:22 ` [PATCH 15/19] coresight: trbe: Add static key for bypassing trigger mode Leo Yan
2025-12-02 12:10 ` Suzuki K Poulose
2025-12-01 11:22 ` [PATCH 16/19] coresight: trbe: Support " Leo Yan
2025-12-01 11:22 ` [PATCH 17/19] coresight: trbe: Enable circle mode for snapshot Leo Yan
2025-12-01 11:22 ` [PATCH 18/19] coresight: trbe: Add kunit tests Leo Yan
2025-12-01 11:22 ` [PATCH 19/19] perf: cs-etm: Set watermark for AUX trace Leo Yan
2025-12-05 4:48 ` Anshuman Khandual
2025-12-09 14:54 ` James Clark
2025-12-10 2:22 ` Anshuman Khandual
2025-12-05 4:53 ` [PATCH 00/19] coresight: trbe: Support trigger and circle buffer modes Anshuman Khandual
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