[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:0.027 / U:46.364 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site