Re: [PATCH] x86/hpet: Reduce HPET counter read contention

From: Andy Lutomirski
Date: Thu Apr 07 2016 - 20:14:08 EST


On Thu, Apr 7, 2016 at 8:07 AM, Waiman Long <waiman.long@xxxxxxx> wrote:
> On 04/07/2016 12:58 AM, Andy Lutomirski wrote:
>> Reading the HPET is so slow that all the atomic ops in the world won't
>> make a dent. Why not just turn this optimization on unconditionally?
>>
>> --Andy
>
>
> I am constantly on the alert that we should not introduce regression on
> lesser systems like a single socket machine with a few cores. That is why I
> put the check to conditionally enable this optimization. I have no issue of
> taking that out and let it be the default as long as no one object.
>

Agreed. I just suspect it's actually faster on all systems.

This reminds me -- I need to send out my patch to disable the vdso
HPET code, which will make your change more effective. I'll cc you.

> Cheers,
> Longman



--
Andy Lutomirski
AMA Capital Management, LLC