linux-kernel - Re: [PATCH 1/1] boot: Enhance performance by eliminating unnecessary calls to printf()

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Message-ID: <55695.1308075820@turing-police.cc.vt.edu>
Date:	Tue, 14 Jun 2011 14:23:40 -0400
From:	Valdis.Kletnieks@...edu
To:	Jean Sacren <sakiwit@...il.com>
Cc:	"H. Peter Anvin" <hpa@...ux.intel.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/1] boot: Enhance performance by eliminating unnecessary calls to printf()

On Sun, 12 Jun 2011 12:36:28 MDT, Jean Sacren said:

> Subject: [PATCH 1/1] boot: Enhance performance by eliminating unnecessary calls to printf()
> 
> Repeated calling to printf() for 13 times is a dire waste of CPU cycles.
> For performance, combine all those calls into one while source code
> formatting is preserved for readability.

*facepalm*

I defy anybody to find a *less* performance-critical piece of code to
micro-optimize. It doesn't even make a boot faster, it makes a kernel build
non-measurably faster.

If you wanted to make kernel builds faster, go look at Ingo's numbers regarding
the current #include mess - fixing *that* will be of more benefit than this...

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