Re: [PATCH] O11int for interactivity

From: Martin Josefsson (gandalf_at_wlug.westbo.se)
Date: 08/05/03

  • Next message: Tomas Szepe: "Re: [TRIVIAL] sanitize power management config menus, take two"
    To: Andrew Morton <akpm@osdl.org>
    Date:	05 Aug 2003 19:00:09 +0200
    
    

    On Tue, 2003-08-05 at 07:55, Andrew Morton wrote:

    > Another possibility is that xmms is getting stuck in a read. The
    > anticipatory scheduler is currently rather tuned for throughput. Judging
    > by the vmstat trace which was posted, we have a classic
    > read-stream-vs-write-stream going on. We trade off latency versus
    > throughput; perhaps wrongly. You can decrease latency (at the expense of
    > throughput) by decreasing the settings in /sys/block/hda/queue/iosched.
    >
    > To a point, it is a nice linear tradeoff, and someone should put the time
    > in to tweak and characterise it.

    I believe it was my trace wli posted.
    No swapping was going on, swappiness set to 30

    X was quite jerky and uninteractive during this and sometimes it froze
    for up to 5 seconds (the sound usually stopped during the freezing).

    Since there wasn't any swapping going on and quite a lot of cpu left we
    either have quite some latency when reading back parts of X that
    previously got discarded or massive stalls in kernelspace somewhere.

    One thing I noticed was that when evolution started checking for new
    mail in a lot of folders I get a lot of seeks and the throughput
    naturally decreased but X got really responsive again. This points away
    from X beeing discarded and read back in from disk since that would take
    some time with all those seeks as well.

    The machine this was tested on is a pIII 700 with 704MB ram and IDE
    disks (everything was against the same disk)
     

    -- 
    /Martin
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  • Next message: Tomas Szepe: "Re: [TRIVIAL] sanitize power management config menus, take two"

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