[lkml]   [2005]   [Feb]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: A scrub daemon (prezeroing)
Rik van Riel writes:

> I'm not convinced. Zeroing a page takes 2000-4000 CPU
> cycles, while faulting the page from RAM into cache takes
> 200-400 CPU cycles per cache line, or 6000-12000 CPU
> cycles.

On my G5 it takes ~200 cycles to zero a whole page. In other words it
takes about the same time to zero a page as to bring in a single cache
line from memory. (PPC has an instruction to establish a whole cache
line of zeroes in modified state without reading anything from

Thus I can't see how prezeroing can ever be a win on ppc64.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 14:10    [W:0.054 / U:6.416 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site