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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: intellectcrew@yahoo.com (samson swanson)
Cc: linux-kernel@vger.kernel.org
Subject: Re: Compiling 2.2.19 with -O3 flag
Date: Fri, 24 May 2002 15:42:26 +0100 (BST)	[thread overview]
Message-ID: <E17BGGw-0006NO-00@the-village.bc.nu> (raw)
In-Reply-To: <20020524065153.15644.qmail@web14309.mail.yahoo.com> from "samson swanson" at May 23, 2002 11:51:53 PM

> I would like to ask when compiling with -O3 flag on a
> kernel such as 2.2.19, what harm / side effect will I
> feel later on if any? will i loose speed in other area's?

Bench it and see. From my own experience -O3 made the kernel a lot larger
and reduced overall performance - in part because the kernel already 
explicitly figures out what it wants inlined.

Interestingly enough -Os outperformed -O2

  reply	other threads:[~2002-05-24 14:22 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-05-24  6:51 Compiling 2.2.19 with -O3 flag samson swanson
2002-05-24 14:42 ` Alan Cox [this message]
2002-05-24 15:19   ` Robert Love
2002-05-24 15:44     ` Alan Cox
2002-05-24 16:45     ` Marcus Meissner
2002-05-24 16:54       ` Robert Love
2002-05-24 17:44         ` Christoph Hellwig
2002-05-24 17:55           ` Robert Love
2002-05-24 18:00             ` Christoph Hellwig

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