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From: Marcus Meissner <mm@ns.caldera.de>
To: linux-kernel@vger.kernel.org
Subject: Re: Compiling 2.2.19 with -O3 flag
Date: Fri, 24 May 2002 18:45:37 +0200	[thread overview]
Message-ID: <200205241645.g4OGjbE30934@ns.caldera.de> (raw)
In-Reply-To: <1022253543.962.236.camel@sinai>

In article <1022253543.962.236.camel@sinai> you wrote:
> On Fri, 2002-05-24 at 07:42, Alan Cox wrote:

>> 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

> Heh, now that is interesting.

Not really, -Os implies -O2, cf gcc/toplev.c:

          if ((p[0] == 's') && (p[1] == 0))
            { 
              optimize_size = 1;

              /* Optimizing for size forces optimize to be 2.  */
              optimize = 2;
            }

CIao, Marcus

  parent reply	other threads:[~2002-05-24 16:45 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
2002-05-24 15:19   ` Robert Love
2002-05-24 15:44     ` Alan Cox
2002-05-24 16:45     ` Marcus Meissner [this message]
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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