From: David Ahern <dsahern@gmail.com>
To: Harald Servat <harald.servat@bsc.es>
Cc: linux-perf-users@vger.kernel.org
Subject: Re: Information regarding the perf tool
Date: Wed, 11 Dec 2013 17:56:40 -0700 [thread overview]
Message-ID: <52A909C8.4060801@gmail.com> (raw)
In-Reply-To: <5277D8E1.9000009@bsc.es>
On 11/4/13, 10:26 AM, Harald Servat wrote:
> On 31/10/13 19:22, David Ahern wrote:
>> On 10/31/13, 11:23 AM, Harald Servat wrote:
>>> Which is the relation between perf_clock() (or local_clock()) and
>>> clock_gettime (CLOCK_MONOTONIC, ). Are they the same? If not, is there a
>>> way to correlate them? Or alternatively, is it possible to call
>>> local_clock() from the userland?
>>
>> We still do not have a means of correlating perf_clock to time-of-day,
>> monotonic or any other clock source. Still trying.
>>
>> Pawell Moll has a couple of patches posted -- one uses an ioctl to get
>> perf_clock timestamps the other makes perf_clock accessible through
>> clock_gettime. See attached.
>>
Coming back to this....
Here is a module version of the posix clock approach:
https://github.com/dsahern/linux/blob/perf-full-monty/README.ahern
As far as I can tell it works for 2.6.38 and forward and there should
not be a conflict with the CLOCK_PERF id of 12. No need to patch and
build your kernel, just build the module, load and go.
That branch also has time-of-day hooks for record, report, script and sched.
David
next prev parent reply other threads:[~2013-12-12 0:56 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-22 16:19 Information regarding the perf tool Harald Servat
2013-10-23 12:47 ` Andi Kleen
2013-10-23 13:51 ` Harald Servat
2013-10-31 15:45 ` Harald Servat
2013-10-31 16:39 ` David Ahern
2013-10-31 17:23 ` Harald Servat
2013-10-31 18:22 ` David Ahern
2013-11-04 17:26 ` Harald Servat
2013-11-04 17:53 ` David Ahern
2013-11-04 18:02 ` Pawel Moll
2013-12-12 0:56 ` David Ahern [this message]
2013-12-12 8:47 ` Harald Servat
2014-01-09 12:11 ` Harald Servat
2013-10-31 16:48 ` Andi Kleen
2013-10-31 16:57 ` Harald Servat
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