From mboxrd@z Thu Jan  1 00:00:00 1970
From: "David S. Miller" <davem@davemloft.net>
Date: Mon, 27 Dec 2004 22:50:57 +0000
Subject: Re: Prezeroing V2 [0/3]: Why and When it works
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To: Linus Torvalds <torvalds@osdl.org>
Cc: arjan@infradead.org, paulus@samba.org, clameter@sgi.com, akpm@osdl.org, linux-ia64@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org

On Fri, 24 Dec 2004 10:21:24 -0800 (PST)
Linus Torvalds <torvalds@osdl.org> wrote:

> Absolutely. I would want to see some real benchmarks before we do this.  
> Not just some microbenchmark of "how many page faults can we take without
> _using_ the page at all".

Here's my small contribution.  I did three "make -j3 vmlinux" timed
runs, one running a kernel without the pre-zeroing stuff applied,
one with it applied.  It did shave a few seconds off the build
consistently.  Here is the before:

real	8m35.248s
user	15m54.132s
sys	1m1.098s

real	8m32.202s
user	15m54.329s
sys	1m0.229s

real	8m31.932s
user	15m54.160s
sys	1m0.245s

and here is the after:

real	8m29.375s
user	15m43.296s
sys	0m59.549s

real	8m28.213s
user	15m39.819s
sys	0m58.790s

real	8m26.140s
user	15m44.145s
sys	0m58.872s