From: Leo Yan <leo.yan@arm.com>
To: James Clark <james.clark@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Mike Leach <mike.leach@linaro.org>,
John Garry <john.g.garry@oracle.com>,
Will Deacon <will@kernel.org>, Leo Yan <leo.yan@linux.dev>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 4/7] perf cs-etm: Don't use hard coded config bits when setting up ETMCR
Date: Tue, 2 Dec 2025 11:43:00 +0000 [thread overview]
Message-ID: <20251202114300.GV724103@e132581.arm.com> (raw)
In-Reply-To: <20251201-james-perf-config-bits-v1-4-22ecbbf8007c@linaro.org>
On Mon, Dec 01, 2025 at 04:41:07PM +0000, Coresight ML wrote:
[...]
> @@ -746,7 +779,7 @@ static void cs_etm_get_metadata(struct perf_cpu cpu, u32 *offset,
> case CS_ETMV3:
> magic = __perf_cs_etmv3_magic;
> /* Get configuration register */
> - info->priv[*offset + CS_ETM_ETMCR] = cs_etm_get_config(itr);
> + info->priv[*offset + CS_ETM_ETMCR] = cs_etm_guess_etmcr(itr);
I still think cs_etm_get_config() is better than cs_etm_guess_etmcr().
For ETMv3, we directly pass CONFIG to the kernel, and after validation
in the dirver, then the value will be set to ETMCR. If we already know
the config value is consistent between user space and kernel, why
introduce a redundant "guess" operation here?
Thanks,
Leo
next prev parent reply other threads:[~2025-12-02 11:43 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-01 16:41 [PATCH 0/7] perf cs-etm/arm-spe: Remove hard coded config fields James Clark
2025-12-01 16:41 ` [PATCH 1/7] perf tools: Track all user changed config bits James Clark
2025-12-02 10:15 ` Leo Yan
2025-12-02 10:40 ` James Clark
2025-12-02 11:21 ` Leo Yan
2025-12-02 12:36 ` Leo Yan
2025-12-01 16:41 ` [PATCH 2/7] perf tools: apply evsel__set_config_if_unset() to all config fields James Clark
2025-12-02 11:14 ` Leo Yan
2025-12-04 10:55 ` James Clark
2025-12-01 16:41 ` [PATCH 3/7] perf cs-etm: Make a helper to find the Coresight evsel James Clark
2025-12-02 11:24 ` Leo Yan
2025-12-01 16:41 ` [PATCH 4/7] perf cs-etm: Don't use hard coded config bits when setting up ETMCR James Clark
2025-12-02 11:43 ` Leo Yan [this message]
2025-12-02 11:53 ` James Clark
2025-12-04 10:55 ` James Clark
2025-12-04 13:45 ` Mike Leach
2025-12-04 13:48 ` James Clark
2025-12-01 16:41 ` [PATCH 5/7] perf cs-etm: Don't use hard coded config bits when setting up TRCCONFIGR James Clark
2025-12-02 12:01 ` Leo Yan
2025-12-01 16:41 ` [PATCH 6/7] perf cs-etm: Don't hard code config attribute when configuring the event James Clark
2025-12-02 12:15 ` Leo Yan
2025-12-04 14:08 ` James Clark
2025-12-04 14:43 ` Leo Yan
2025-12-01 16:41 ` [PATCH 7/7] perf arm-spe: Don't hard code config attribute James Clark
2025-12-02 12:28 ` Leo Yan
2025-12-02 12:42 ` Leo Yan
2025-12-02 12:59 ` James Clark
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