From: peterz@infradead.org
To: Andi Kleen <ak@linux.intel.com>
Cc: "Jiri Olsa" <jolsa@redhat.com>, "David Ahern" <dsahern@gmail.com>,
"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>,
"Michael Petlan" <mpetlan@redhat.com>,
"Ian Rogers" <irogers@google.com>,
"Geneviève Bastien" <gbastien@versatic.net>,
"Wang Nan" <wangnan0@huawei.com>,
"Jeremie Galarneau" <jgalar@efficios.com>
Subject: Re: [PATCH 0/6] perf tools: Add wallclock time conversion support
Date: Fri, 31 Jul 2020 20:05:39 +0200 [thread overview]
Message-ID: <20200731180539.GA2674@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200731153612.GC1299820@tassilo.jf.intel.com>
On Fri, Jul 31, 2020 at 08:36:12AM -0700, Andi Kleen wrote:
> > yep, we have a customer that needs to compare data from multiple servers
>
> It's also needed to correlate over different guests on the same machine.
> This is an important use case.
Both these cases you want to sync up CLOCK_MONOTONIC, using walltime is
just utterly misguided.
What happens if the servers have (per accident or otherwise) different
DST settings, or someone does a clock_setttime() for giggles.
All you really want is a clock that runs at the same rate but is not
subject to random jumps and user foibles.
next prev parent reply other threads:[~2020-07-31 18:05 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
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 [this message]
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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