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From: Ian Kumlien <>
Subject: [SHED][IO-SHED] Are we missing the big picture?
Date: 01 Aug 2003 02:32:02 +0200	[thread overview]
Message-ID: <> (raw)

Hi all,

I have been following the sheduler and interactivity discussions closely
but via the archive, So i might be behind etc...

[Note: sorry if i sound like mr.know-it-all etc, just trying to get a
point across]

Anyways, i think that the AS discussions that i have seen has missed
some points. Getting the processes priority in AS is one thing, but fist
of all i think there should be a stand off layer. Let me explain:

I liked Jens Axobe's 'CBQ' alike implementation (based on the idea of
Andrea A. (afair i have the names right) since it does the most
important thing... which is *nothing* when there is no load (ie, pass

AS might be/is the best damn io sheduler for loaded machines but when
there is no load, it's overhead. So in my opinion there should be
something that first warrants the usage of AS before it's actually

And, if it's only engaged during high load, additions like basing the
requests priority on the process/tasks priority would make total sense,
adding the 'wakeup on wait' or what it was would also make total
sense... But how many of your machines uses the disk 100% of the time?
(in the real world... )

I don't know how 'CBQ' was implemented but any 'we are under load now'
trigger would do it for me.

Please see to it that my CC is included in any discussions =)

PS. Or was it a version of SFQ? in that case s/CBQ/SFQ/g

Ian Kumlien <>

             reply	other threads:[~2003-08-01  0:33 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-08-01  0:32 Ian Kumlien [this message]
2003-08-01  6:27 ` [SHED][IO-SHED] Are we missing the big picture? Nick Piggin
2003-08-01 12:18   ` Ian Kumlien
2003-08-02  1:49     ` Nick Piggin
2003-08-02  2:07       ` Ian Kumlien
     [not found] <>
2003-08-01  9:00 ` Ihar "Philips" Filipau
2003-08-01 12:23   ` Ian Kumlien
2003-08-01 12:32     ` Jens Axboe
2003-08-01 13:01       ` Ian Kumlien

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