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From: michel.dagenais@polymtl.ca (Michel Dagenais)
Subject: [ltt-dev] Experiments on CPU time statistics
Date: Thu, 11 Nov 2010 14:23:50 -0500	[thread overview]
Message-ID: <4CDC42C6.5030109@polymtl.ca> (raw)
In-Reply-To: <20101111185944.GA27102@Krystal>


>> time statistics:
>> real	0m10.715s
>>
>> user	0m0.420s
>>
>> sys	0m6.350s
...
> Elapsed time is the total of the per-thread elapsed time I think (it's
> really been a while since I played with this code though). It would make
> sense if you have 54 threads in your system.
>
> I don't have entire confidence that the elapsed time is correct.

As a side note, while the elapsed time provided by "time" is probably 
reliable, the user and system time are obtained by sampling under 
asumptions which are sometimes not met. Arbitrarily large deviations 
from the reality are possible. The CPU time computed from the LTTng 
trace data is exact, not statistical.



  reply	other threads:[~2010-11-11 19:23 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-11 17:50 Francis Giraldeau
2010-11-11 18:59 ` Mathieu Desnoyers
2010-11-11 19:23   ` Michel Dagenais [this message]
2010-11-11 21:05   ` Francis Giraldeau

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