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

[Peter Zijlstra]

On Fri, 2010-11-19 at 21:11 +0100, Michael Holzheu wrote:
> 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.
> 
> To solve this problem, this patch set duplicates the cumulative accounting
> data in the signal_struct. In the second set (cdata_acct) the complete
> cumulative resource counters are stored. The new cumulative CPU time (utime
> and stime) is then exported via the taskstats interface. 

Maybe this has been treated earlier in the threads and I missed it, but
the obvious solution doesn't get mentioned:

What would break if we violate this silly POSIX rule and account time of
childs regardless of SIGCHLD/SA_NOCLDWAIT?


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