Re: [resent PATCH] Re: very slow parallel read performance

Lehmann
2001-08-26T19:31:19Z

On Sun, Aug 26, 2001 at 06:54:55PM +0200, Daniel Phillips <phillips@bonn-fries.net> wrote:
> But it's a very interesting idea: instead of performing readahead in
> generic_file_read the user thread would calculate the readahead window

More basic, less interesting but far more useful would be real aio, sicne
this would get rid of hundreds of threads that need manual killing when the
server crashes during development and keep the accept socket open ;)

(But it seems we will have sth. like that in 2.6, so I am generally happy
;)

> submit. The user thread benefits by avoiding some stalls due to
> readahead->readpage, as well as avoiding thrashing due to excessive
> readahead.

In an ideal world, I would not need user buffers as well and could just
tell the kernel "copy from file to network", but that requires too much
kernel tinkery I believe (although, when there is generic aio in the
kernel there might some day be a aio_sendfile ;)

--
-----==- |
----==-- _ |
---==---(_)__ __ ____ __ Marc Lehmann +--
--==---/ / _ \/ // /\ \/ / pcg@goof.com |e|
-=====/_/_//_/\_,_/ /_/\_\ XX11-RIPE --+
The choice of a GNU generation |
|