Re: 2.6.35-rc3: System unresponsive under load

From: Luca Tettamanti
Date: Tue Jul 06 2010 - 12:01:52 EST


On Wed, Jun 30, 2010 at 9:07 PM, Manfred Spraul
<manfred@xxxxxxxxxxxxxxxx> wrote:
> Attached is a new idea, could you try it with your httpd test?

Will test ASAP.

> Perhaps the race is actually a race in the user space:
> The exit path of semtimedop() does not contain an explicit memory barrier.
> For the kernel, it does not matter: It merely reads one integer value.
> If sysret is also no memory barrier, then user space might observe stale
> data.
>
> Which cpu do you have? I was unable to show any misbehavior on a Phenom X4.

Intel(R) Core(TM)2 Duo CPU T7500 @ 2.20GHz

I also have a Phenom X4, but I'm currently waiting a replacement for the PSU...

Luca
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