Chen, Kenneth W wrote on Tuesday, March 28, 2006 11:32 PM > Christoph Lameter wrote on Tuesday, March 28, 2006 11:16 PM > > > > I saw David Mosberger's patch from last year > > > > and it seems that he implemented fast handling of these NULL cases? > > I know about that patch and I'm referring in the context of that commit: > > ld8.s r1=[r0] - immediate nat generation, no fault > lfetch.fault [r0] - generate nat page consumption because lfetch is not > considered as a speculative access. > > The nat page consumption fault handler should be rather quick, though cpu > still have to fault into the handler, muck around with ipsr.ed bit and > then rfi. What I'm saying is there is an even *faster* way of doing > prefetch. One other caveat with this is that if you have a tlb miss on mm->mmap_sem, it won't prefetch anything because alt_dtlb_miss handler will nuke the ld8.s or lfetch instruction :-( - Ken - : send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
|