Messages in this thread | | | Date | Sun, 15 Jun 2014 15:14:16 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v11 09/16] qspinlock, x86: Allow unfair spinlock in a virtual guest |
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On Thu, Jun 12, 2014 at 05:08:28PM -0400, Waiman Long wrote: > >Native performance is king, try your very utmost bestest to preserve > >that, paravirt is a distant second and nobody sane should care about the > >virt case at all. > > The patch won't affect native performance unless the kernel is built with > VIRT_UNFAIR_LOCKS selected. The same is also true when PARAVIRT_SPINLOCKS is > selected. There is no way around that.
VIRT_UNFAIR_LOCKS is an impossible switch to have; a distro cannot make the right choice.
> I do agree that I may over-engineer on this patch,
Simple things first, then add complexity.
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