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From: David Ahern <dsahern@gmail.com>
To: Jiri Olsa <jolsa@redhat.com>,
	Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: "Jiri Olsa" <jolsa@kernel.org>,
	"Arnaldo Carvalho de Melo" <acme@kernel.org>,
	lkml <linux-kernel@vger.kernel.org>,
	"Ingo Molnar" <mingo@kernel.org>,
	"Namhyung Kim" <namhyung@kernel.org>,
	"Alexander Shishkin" <alexander.shishkin@linux.intel.com>,
	"Peter Zijlstra" <a.p.zijlstra@chello.nl>,
	"Michael Petlan" <mpetlan@redhat.com>,
	"Ian Rogers" <irogers@google.com>,
	"Andi Kleen" <ak@linux.intel.com>,
	"Geneviève Bastien" <gbastien@versatic.net>,
	"Wang Nan" <wangnan0@huawei.com>,
	"Jeremie Galarneau" <jgalar@efficios.com>
Subject: Re: [PATCH 2/6] perf tools: Store clock references for -k/--clockid option
Date: Fri, 31 Jul 2020 10:35:54 -0600	[thread overview]
Message-ID: <f24e38b0-3000-1306-7058-cc440557e733@gmail.com> (raw)
In-Reply-To: <20200731161519.GB4296@krava>

On 7/31/20 10:15 AM, Jiri Olsa wrote:
>> It might also want to be implemented in a loop and iteration with minimal
>> time delta is chosen to improve synchronization accuracy and also mitigate
>> possible context switches between gettimeofday() and clock_gettime() calls.
> right, we could make this more accurate.. I'll post some follow up
> change with that

If it is handled through vdso (e.g., x86) both calls should be very fast
with no context switches and the margin of error is well less than the
usec resolution in the output.

  reply	other threads:[~2020-07-31 16:35 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-30 21:39 [PATCH 0/6] perf tools: Add wallclock time conversion support Jiri Olsa
2020-07-30 21:39 ` [PATCH 1/6] perf tools: Add clockid_name function Jiri Olsa
2020-07-31 15:33   ` Andi Kleen
2020-07-31 16:19     ` Jiri Olsa
2020-07-30 21:39 ` [PATCH 2/6] perf tools: Store clock references for -k/--clockid option Jiri Olsa
2020-07-31 15:52   ` Alexey Budankov
2020-07-31 16:15     ` Jiri Olsa
2020-07-31 16:35       ` David Ahern [this message]
2020-08-03  3:55   ` Namhyung Kim
2020-08-03 11:35     ` Jiri Olsa
2020-07-30 21:39 ` [PATCH 3/6] perf tools: Move clockid_res_ns under clock struct Jiri Olsa
2020-07-30 21:39 ` [PATCH 4/6] perf tools: Add support to store time of day in CTF data conversion Jiri Olsa
2020-08-03  4:00   ` Namhyung Kim
2020-08-03 11:31     ` Jiri Olsa
2020-07-30 21:39 ` [PATCH 5/6] perf script: Change enum perf_output_field values to be 64 bits Jiri Olsa
2020-07-30 21:39 ` [PATCH 6/6] perf script: Add tod field to display time of day Jiri Olsa
2020-07-30 22:14 ` [PATCH 0/6] perf tools: Add wallclock time conversion support peterz
2020-07-31  1:21   ` David Ahern
2020-07-31  7:47     ` Jiri Olsa
2020-07-31 15:36       ` Andi Kleen
2020-07-31 18:05         ` peterz
2020-08-01  0:46           ` David Ahern
2020-08-01 17:49             ` Arnaldo Carvalho de Melo
2020-07-31 17:20     ` peterz

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