Re: [PATCH] Radix-tree pagecache for 2.5

[Jeff Garzik]

On Fri, Feb 01, 2002 at 06:44:50PM +0000, [e-mail] wrote:
> In article <[e-mail]> you 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.
> 
> the biggest reason for this is that we *suck* at readahead for mmap....

Is there not also fault overhead and similar issues related to mmap(2)
in general, that are not present with read(2)/write(2)?

	Jeff