lkml.org 
[lkml]   [2001]   [Dec]   [31]   [last100]   RSS Feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
/
DateMon, 31 Dec 2001 11:58:27 +0100
FromManfred Spraul <>
SubjectRe: [patch] Prefetching file_read_actor()
Andrew Morton wrote:
> 
> 
> Is prefetching 4k at a time optimal?  Should the prefetch be embedded
> in copy_*_user?
>
For the Pentium III, that's the Intel recommended sequence.

> 
> The code makes no attempt to align the prefetch address to anything.
> Should it?

Not needed.

> What happens if a prefetch spills over the end of the page and
> faults?
>
Doesn't hurt, prefetch instruction never cause page faults.
BUT: Prefetch doesn't preload the TLB. If the TLB entry for the kmap is
not in the TLB, all prefetch instructions are treated as nops.(on pIII).

--
	Manfred
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 12:14    [from the cache]
©2003-2008