Re: [patch 0/4] taskstats: Improve cumulative time accounting

From: Valdis . Kletnieks
Date: Mon Nov 22 2010 - 13:12:54 EST


On Mon, 22 Nov 2010 13:47:55 +0100, Michael Holzheu said:

> Currently the cumulative time accounting in Linux is not complete.
> Due to POSIX POSIX.1-2001, the CPU time of processes is not accounted
> to the cumulative time of the parents, if the parents ignore SIGCHLD
> or have set SA_NOCLDWAIT. This behaviour has the major drawback that
> it is not possible to calculate all consumed CPU time of a system by
> looking at the current tasks. CPU time can be lost.
>
> This patch adds a new sysctl "kernel.full_cdata" that allows to switch
> between the POSIX behavior and complete cumulative accounting.

> +unsigned int full_cdata_enabled = 1;

This probably needs to default to "current kernel behavior" but allow
sysadmins to change to the new behavior.

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