Re: [PATCH 00/36] cputime: Convert core use of cputime_t to nsecs

From: Ingo Molnar
Date: Mon Nov 21 2016 - 04:49:31 EST



* Frederic Weisbecker <fweisbec@xxxxxxxxx> wrote:

> > But I am still not happy about the approach. What is the compelling reason for
> > this change except for the "but it looks ugly"?
>
> The diffstat (600 lines removed). Also the fact that we have all these
> workarounds in the core code just for the special case of 1 arch (s390) and a
> half (powerpc with CONFIG_VIRT_CPU_ACCOUNTING_NATIVE).
>
> I'd much rather have all that complexity moved in a vtime_native.c shared by
> s390 and powerpc that takes care of proper accumulation in cputime_t and flushes
> that on ticks in nsecs rather than having all these cputime_t game all over the
> kernel.

I agree - we really want to concentrate complexity in such a fashion and generally
standardize on nanosecs, and the diffstat of the patchset is really nice.

The patchset obviously has to build (and work!) on s390/powerpc properly.

Thanks,

Ingo