fastboot, diskstat

From: bert hubert (bert.hubert_at_netherlabs.nl)
Date: 07/22/05

  • Next message: Peter Williams: "Re: 2.6.13-rc3-mm1 (ckrm)" 
    Date:	Fri, 22 Jul 2005 05:41:35 +0200
To: Andrew Morton <akpm@osdl.org>

    Hi Andrew,

    I'm currently at OLS and presented http://ds9a.nl/diskstat yesterday, which
    also references your ancient 'fboot' program.

    I've also done experiments along those lines, and will be doing more of them
    soon.

    You mention it was a waste of time, do you recall if that meant:

    1) that the total time for prefetching + actual boot was only 10% shorter,
    but that the actual booting did not (significantly) touch the disk?

    2) that on actual boot there would still be a lot of i/o

    ?

    Regarding 1), in my own experiments I failed to convince the kernel to
    actually cache the pages I touched, I wonder if some sequential-read
    detection kicked in, the one that prevents entire cd's being cached.

    For my next attempt I'll try to actually lock the pages into memory.

    Also, regarding the directory entries, are they accessed via the buffer
    cache? Iow, would reading blocks which can't be mapped to files directly via
    /dev/hda be useful?

    Thanks! 

    -- 
http://www.PowerDNS.com      Open source, database driven DNS Software 
http://netherlabs.nl              Open and Closed source services
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