[lkml]   [2002]   [Feb]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] Radix-tree pagecache for 2.5
Jeff Garzik wrote:
> On Fri, Feb 01, 2002 at 09:06:37AM -0800, Linus Torvalds wrote:
> > Even databases often use multiple files, and quite frankly, a database
> > that doesn't use mmap and doesn't try very hard to not cause extra system
> > calls is going to be bad performance-wise _regardless_ of any page cache
> > locking.
> I've always thought that read(2) and write(2) would in the end wind up
> faster than mmap(2)... Tests in my rewritten cp/rm/mv type utilities
> seem to bear this out.
> Is mmap(2) only preferred for large files/databases?

I've tried to make faster md5summing program and programmed several
ways of accessing file - for the very large files the fastest
way seemed to be O_DIRECT with threaded precaching.

For fast mmap access I'd to implement two parallel mmpad areas with
madvise MADV_WILLNEED - then it was almost as fast as read

.''`. Which fundamental human right do you want to give up today?
: :' : Debian GNU/Linux maintainer - www.debian.{org,cz}
`. `' Zdenek Kabelac kabi@{,,}
`- When in doubt, just blame the Euro. :)

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 13:23    [W:0.083 / U:14.116 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site