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From: Vincent Lefevre <vincent@vinc17.net>
To: zsh-workers@zsh.org
Subject: Re: miscomputation of total time?
Date: Fri, 30 Apr 2021 12:25:58 +0200
Message-ID: <20210430102558.GA1183927@zira.vinc17.org> (raw)
In-Reply-To: <20210430095057.GA1181586@zira.vinc17.org>

On 2021-04-30 11:50:57 +0200, Vincent Lefevre wrote:
> I use REPORTTIME=60, and on a Debian 10 machine (I haven't tried on
> others) with zsh 5.7.1, I've noticed that the fraction of second in
> the total time (the 2 digits between the period and " total") is not
> random as expected: on the 370 runs in the past few months, I get a
> value always between 17 and 99. Moreover, values from 17 to 47 occur
> much more often than values from 48 to 99 (325 values vs 45).
> Statistically, these values should be random between 00 and 99.
> 
> Is there an error in the computation of the total time?

Sorry, I think that I found the cause. I forgot that the process
in question was multithreaded, with a main thread waiting for the
others (even on this machine with 1 core). A check is done every
second with a "sleep 1", so that I think that the total time is
an integer number of seconds + some overhead.

-- 
Vincent Lefèvre <vincent@vinc17.net> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)


      reply	other threads:[~2021-04-30 10:26 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-30  9:50 Vincent Lefevre
2021-04-30 10:25 ` Vincent Lefevre [this message]

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