Messages in this thread | | | Date | Tue, 21 Feb 2012 17:32:52 -0800 | From | "Paul E. McKenney" <> | Subject | Re: Large slowdown with 'x86: Avoid invoking RCU when CPU is idle' |
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On Tue, Feb 21, 2012 at 08:16:53PM -0500, Josh Boyer wrote: > Hi Paul, > > Over in Fedora land, I applied your patch from this thread: > > https://lkml.org/lkml/2012/1/24/441 > > to our 3.3-rc3/rc4 based rawhide kernels. The intention was to solve an > RCU issue that was very similar to what Eric originally reported, and > the RCU splat did indeed go away[1]. > > However, we then got a few reports of kernels containing that patch > being extremely slow. When the patch was dropped, the slowness goes > away according to one reporter. The details can be found in this bug: > > https://bugzilla.redhat.com/show_bug.cgi?id=795050 > > The slowness doesn't seem to hit everyone, and in my local testing > things seem to be working just fine. The reporters have widely varying > hardware as well, so it doesn't seem machine specific. > > Perhaps I misdiagnosed the original issue, or perhaps I missed something > else that needs to be applied prior to this but I thought I would point > this out in case you had any ideas.
This patch has been obsoleted by patches #45-47 in this series:
https://lkml.org/lkml/2012/2/3/459
And patch #47 in that series has been obsoleted by another series from Steven Rostedt:
https://lkml.org/lkml/2012/2/7/231
Hopefully these fix both splats and slowness.
Thanx, Paul
> josh > > [1] https://bugzilla.redhat.com/show_bug.cgi?id=789641 >
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