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From: Oliver Neukum <oliver@neukum.name>
To: robw@optonline.net
Subject: Re: any chance of 2.6.0-test*?
Date: Sun, 12 Jan 2003 23:38:20 +0100
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References: <Pine.LNX.4.44.0301121100380.14031-100000@home.transmeta.com> <20030112215949.GA2392@www.kroptech.com> <1042410059.1208.150.camel@RobsPC.RobertWilkens.com>
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Am Sonntag, 12. Januar 2003 23:21 schrieb Rob Wilkens:
> On Sun, 2003-01-12 at 16:59, Adam Kropelin wrote:
> > Congratulations. You've possibly increased the speed of an error path by
> > an infintessimal amount at the expense of increasing the size of kernel
> > image and making the code harder to read and maintain. (I say "possibly"
> > since with caching effects you may have actually slowed the code down.)
>
> Hey, if the compiler does it's job right, I increased the speed of
> something in the kernel.  And, as a kernel newbie, I'm proud of that.  I
> also did it in under 12 minutes (from time stamp of message received to
> time stamp of message sent after code compiled and diff'd).

Nope you didn't.
Any compiler that can move outline code like
if (con) {
	cleanup()
	return err;
}
can easily simplify
if (con)
	goto err_out;
into a single branch. Still you have enlarged the kernel a bit.
With the same number of jumps, as a rule of thumb, the smaller
code is faster.

	Regards
		Oliver

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