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From: Adrian Hunter <adrian.hunter@intel.com>
To: Leo Yan <leo.yan@linaro.org>, Al Grant <Al.Grant@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
	John Garry <john.garry@huawei.com>, Will Deacon <will@kernel.org>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	James Clark <James.Clark@arm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Mark Rutland <Mark.Rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 0/7] perf arm-spe: Enable timestamp
Date: Wed, 7 Apr 2021 16:28:40 +0300	[thread overview]
Message-ID: <0016288d-a490-f8fb-f108-0969b946494e@intel.com> (raw)
In-Reply-To: <20210407131529.GA585163@leoy-ThinkPad-X240s>

On 7/04/21 4:15 pm, Leo Yan wrote:
> Hi Al,
> 
> On Tue, Apr 06, 2021 at 09:38:32AM +0000, Al Grant wrote:
> 
> [...]
> 
>>> This patch set is to enable timestamp for Arm SPE trace.  It reads out TSC
>>> parameters from mmap page and stores into auxtrace info structure;
>>
>> Why not synthesize a PERF_RECORD_TIME_CONV - isn't that specifically to
>> capture the TSC parameters from the mmap page? If a generic mechanism
>> exists it would be better to use it, otherwise we'll have to do this again for
>> future trace formats.
> 
> Good point!  Actually "perf record" tool has synthesized event
> PERF_RECORD_TIME_CONV.  This patch series is studying the
> implementation from Intel-PT, so the question is why the existed
> implementations (like Intel-PT, Intel-BTS) don't directly use
> PERF_RECORD_TIME_CONV for retriving TSC parameters.

PERF_RECORD_TIME_CONV was added later because the TSC information is
needed by jitdump.


  reply	other threads:[~2021-04-07 13:28 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-03  7:23 [PATCH v2 0/7] perf arm-spe: Enable timestamp Leo Yan
2021-04-03  7:23 ` [PATCH v2 1/7] perf arm-spe: Remove unused enum value ARM_SPE_PER_CPU_MMAPS Leo Yan
2021-04-03  7:23 ` [PATCH v2 2/7] perf arm-spe: Store TSC parameters in auxtrace info Leo Yan
2021-04-03  7:23 ` [PATCH v2 3/7] perf arm-spe: Dump TSC parameters Leo Yan
2021-04-03  7:23 ` [PATCH v2 4/7] perf arm-spe: Convert event kernel time to counter value Leo Yan
2021-04-03  7:23 ` [PATCH v2 5/7] perf arm-spe: Assign kernel time to synthesized event Leo Yan
2021-04-03  7:23 ` [PATCH v2 6/7] perf arm-spe: Bail out if the trace is later than perf event Leo Yan
2021-04-03  7:23 ` [PATCH v2 7/7] perf arm-spe: Don't wait for PERF_RECORD_EXIT event Leo Yan
2021-04-06  9:38 ` [PATCH v2 0/7] perf arm-spe: Enable timestamp Al Grant
2021-04-07 13:15   ` Leo Yan
2021-04-07 13:28     ` Adrian Hunter [this message]
2021-04-07 13:40       ` Leo Yan

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