Re: [PATCH 0/4] i386 - pte update optimizations

H. Peter Anvin
2007-04-13T15:35:13Z

Keir Fraser wrote:
> On 13/4/07 13:27, "Andi Kleen" <andi@firstfloor.org> wrote:
>
>>> LOCKed instruction suck really badly on the netburst microarchitecture (like
>>> factor of 10x, or not far off). I think it's probably because of their side
>>> effect of serialising memory accesses, causing horrible pipeline stalls.
>> Unfortunately they tend to be HyperThreaded usually (except for early ones
>> and Celerons) and need the LOCK anyways.
>
> Fair point, although quite a few people disable HT.

Note we're talking a UP-only hack.

-hpa