lkml.org 
[lkml]   [2013]   [Dec]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] x86 idle: repair large-server 50-watt idle-power regression
On Thu, Dec 19, 2013 at 06:25:35PM +0100, Peter Zijlstra wrote:
> On Thu, Dec 19, 2013 at 06:07:41PM +0100, Ingo Molnar wrote:
> > Likewise, having a barrier before the MONITOR looks sensible as well.
>
> I again have to disagree, one would expect monitor to flush all that is
> required to start the monitor -- and it actually does so. As is
> testified by this extra CLFLUSH being called a bug workaround.

SDM states that MONITOR is ordered like a LOAD, and a LOAD cannot pass
a previous STORE to the same address.

That said; there's enough holes in there to swim a titanic through,
seeing how MONITOR stares at an entire cacheline and LOAD/STORE order is
specified on location, whatever that means.




\
 
 \ /
  Last update: 2013-12-22 09:41    [W:0.322 / U:0.348 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site