From: Leo Yan <leo.yan@arm.com>
To: James Clark <james.clark@linaro.org>
Cc: 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>,
Anshuman Khandual <anshuman.khandual@arm.com>,
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 07/19] coresight: trbe: Refactor AUX flag setting
Date: Fri, 12 Dec 2025 15:27:38 +0000 [thread overview]
Message-ID: <20251212152738.GA181228@e132581.arm.com> (raw)
In-Reply-To: <27417fd5-902e-4474-8d60-356a94ac9590@linaro.org>
On Fri, Dec 12, 2025 at 04:50:52PM +0200, James Clark wrote:
[...]
> > The trace can be stopped on Fill mode (stop on wrap) or Stop on trigger, so
> > it is not (only) about buffer error. In these cases, even though the trace
> > unit is stopped, the buffer may still have space available, tracing can be
> > directly re-enabled in interrupt handler, thus the COLLISION/PARTIAL flags
> > are better choices.
>
> I suppose this is the bit that I don't understand. If there is space left
> then why is the stop hit at all?
For instance, the buffer becomes empty in the middle:
+----------------------------+
|$$$$$$$| |$$$$$$$|
+----------------------------+
` base `wptr `limit
In this case, the trace unit stops when it reaches the limit.
Meanwhile, the tool might have already read out the old trace data so
we will get some free space, thus no need to set TRUNCATED flag.
next prev parent reply other threads:[~2025-12-12 15:27 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 [this message]
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
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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