Re: Memset very slow

Brian D. McGrew
2011-02-03T21:58:17Z

On 2/3/11 1:31 PM, "Alan Cox" <alan@lxorguk.ukuu.org.uk> wrote:

>> So, my question is, can someone explain to me what is going on here? I am
>> not convinced this is a kernel problem just because a new kernel fixed it;
>> but, if there were changes related to this in the kernel, then what is the
>> oldest version I should be looking at to fix my issues?
>
> The newer kernel does several things that may be relevant - the obvious
> one is that it rewrites and corrects MTRR data if it doesn't like what
> the BIOS handed out. That would fit with dramatic slowdowns in memory
> performance being fixed.

The Dell precsion-linux mailing list almost immediately pointed me here:
https://bugzilla.redhat.com/show_bug.cgi?id=581933

Which seems like it is my problem and the fix seems to work for me.

-brian