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DragonFly kernel List (threaded) for 2005-06
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To: Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx>
From: Hiten Pandya <hmp@xxxxxxxxxxxxx>
Date: Thu, 02 Jun 2005 21:48:40 +0100

Matthew Dillon wrote:
:Matt, I don't think this is a good to rush. I think it can seriously degrade
:performance, esp. since some of the spl() protections are hold over longer
:areas of time.
:I don't have a problem with replacing critical short usage areas with
:critical sections, but flatting it directly is not good.

    Joerg, we've been juggling the SPL issue since day 1.  The time has come
    to remove them.

    And, again, I completely disagree with your performance concerns.  I
    challenge you to find a case where performance would be degraded.
    The most widely used long-held SPLs in the system are SPLBIO and SPLVM,
    and guess what?  They pretty much mask ALL MAJOR DEVICES anyway.  So
    what's the point of having a variable mask in the first place?  No
    point at all...

In order to get things fixed, it is important to make them work first, then make them right and then think about performance issues. Always thinking performance first is not good. Little lesson in philosophy for our fellow committers. :-)

Hiten Pandya

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