From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 8313B30BBAB; Wed, 26 Nov 2025 15:14:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764170094; cv=none; b=Y2x57NybfQMy6cyG8QeUZcdqpPzoYB7U0+3FUohg3yKAo1hfrqk+pr+lK7nO7xB9WU/Xt2Ph7ybuV/CVhgZ2qFsOsBe8yPEuZ32oFYe6YmXIK3vuCcUkVqW+85p0syOKN1ioKFcW6UFq1LUZSAHKbOKitKP3kCP5gqi36Eb7lO4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764170094; c=relaxed/simple; bh=kG4BplKErAnfo/TlorB7v9/ErMxgI4gloPeVD8rAA9M=; h=Date:From:To:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=dwBFDjKvh8JQuUeIhA//qlTCLRIClxEPDGZiZo6ZnRaGQAuIixei16FVJm5S1hbM2z2RgSCYlri0ByTISFazzFKo6387dyVCdSKYrRyPM70eGlylDcb0yk6Vh81Ci3VQaPOE9OfKeE2LYslwKjcbv787WEsLz3c0QF4SG4vOeJ0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 535A7168F; Wed, 26 Nov 2025 07:14:43 -0800 (PST) Received: from localhost (e132581.arm.com [10.1.196.87]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 626683F66E; Wed, 26 Nov 2025 07:14:50 -0800 (PST) Date: Wed, 26 Nov 2025 15:14:48 +0000 From: Leo Yan To: Mike Leach , James Clark , Alexander Shishkin , Jonathan Corbet , Randy Dunlap , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [PATCH v7 13/13] coresight: docs: Document etm4x timestamp interval option Message-ID: <20251126151448.GM724103@e132581.arm.com> References: <20251126-james-cs-syncfreq-v7-0-7fae5e0e5e16@linaro.org> <20251126-james-cs-syncfreq-v7-13-7fae5e0e5e16@linaro.org> <20251126140154.GK724103@e132581.arm.com> <20251126144437.GL724103@e132581.arm.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251126144437.GL724103@e132581.arm.com> On Wed, Nov 26, 2025 at 02:44:37PM +0000, Coresight ML wrote: [...] > > As far as I recall when this command line parameter was a bool then: > > perf -e cs_etm/timestamp/ > > is sufficient to turn on timestamping. > > Hmm... with the latest perf, we must assign value to `timestamp`, > otherwise perf will report error: > > # /mnt/build/perf record -e cs_etm/timestamp/ -C 0 -- taskset -c 0 ls > event syntax error: 'cs_etm/timestamp/' > \___ Bad event or PMU > > Unable to find PMU or event on a PMU of 'cs_etm' > > event syntax error: 'cs_etm/timestamp/' > \___ no value assigned for term > > event syntax error: 'cs_etm/timestamp/' > \___ no value assigned for term > Run 'perf list' for a list of valid events Apologize for this misinformation. When `timestamp` is bool, it does support the `-e cs_etm/timestamp/` format. > > This is worth mentioning so users can correctly assess what happens > > for any existing scripts they might have. > > > > Based on this then the same command must set the timestamp to 1 - > > which will have the same effect as before as we do not want to break > > existing behaviour. Not sure if we need to record such info. Seems to me, it is weird that record a common behaviour for perf formats in this doc. The perf error log would be sufficient for users to setup a proper format? Thanks, Leo