[lkml]   [1999]   [Jul]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: (disk/cpu) kernel performance problem
On Mon, 26 Jul 1999, Gerald Aigner wrote:

> While optimizing the program I discovered that disk I/O
> performance in Linux could be improved substantially. In
> particular, there are two main problems:
> 1) The kernel copies data many times before it ends up in user
> space.

I'm very sorry, but you seem to be too late. This problem is
(at least partially) fixed in the newer 2.3 kernels...

> 2) Using mmap doesn't help because it serializes I/O within a single
> process (you can't read simultaneously from two disks).

A single process uses a single thread of control, and yes,
we do readahead over RAID0 sets...

If you want to do true async I/O, you can just use the
interface glibc gives you to do that.

Rik -- Open Source: you deserve to be in control of your data.
| Le Reseau netwerksystemen BV: |
| Linux Memory Management site: |
| Nederlandse Linux documentatie: |

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

 \ /
  Last update: 2005-03-22 13:53    [W:0.095 / U:0.304 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site