From: David Howells <dhowells@redhat.com>
To: "Aubrey Li" <aubreylee@gmail.com>
Cc: "Alan Cox" <alan@lxorguk.ukuu.org.uk>,
vapier.adi@gmail.com, jie.zhang@analog.com, bryan.wu@analog.com,
"Andrew Morton" <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] nommu arch dont zero the anonymous mapping by adding UNINITIALIZE flag
Date: Fri, 30 Mar 2007 16:11:17 +0100 [thread overview]
Message-ID: <12871.1175267477@redhat.com> (raw)
In-Reply-To: <6d6a94c50703300738i7b9d3fcn341feb08dca8817d@mail.gmail.com>
Aubrey Li <aubreylee@gmail.com> wrote:
> Summary is, when I run the app "time test",
>
> on x86:
> real 0m0.066s
> user 0m0.008s
> sys 0m0.058s
>
> on Blackfin:
> real 3m 37.69s
> user 0m 0.04s
> sys 3m 37.58s
That's not a good comparison: you're comparing two different machines of two
different archs.
> Keep the same behave as MMU but with bad performance, or keep the same
> performance as MMU but without the same behave, Which one is more
> important?
The thing to do is to pass a flag to mmap() to suppress the memset (as
suggested). This can then be used by the uClibc malloc() implementation and
does not impact any application that does an anon mmap() expecting the memory
returned to be zeroed.
David
next prev parent reply other threads:[~2007-03-30 15:13 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-30 3:42 [PATCH] nommu arch dont zero the anonymous mapping by adding UNINITIALIZE flag Wu, Bryan
2007-03-30 3:53 ` Mike Frysinger
2007-03-30 9:39 ` David Howells
2007-03-30 10:34 ` Aubrey Li
2007-03-30 11:24 ` David Howells
2007-03-30 13:44 ` Aubrey Li
2007-03-30 14:56 ` Alan Cox
2007-03-30 14:38 ` Aubrey Li
2007-03-30 15:11 ` David Howells [this message]
2007-03-30 15:46 ` Aubrey Li
2009-10-13 7:44 ` [PATCH] NOMMU: fix malloc performance by adding uninitialized flag Mike Frysinger
2009-10-13 10:10 ` David Howells
2009-10-13 11:20 ` [PATCH v2] " Mike Frysinger
2009-10-13 13:03 ` Paul Mundt
2009-10-13 16:03 ` David Howells
2009-10-13 21:31 ` [PATCH v3] " Mike Frysinger
2009-10-13 23:04 ` David McCullough
2009-10-14 0:25 ` Greg Ungerer
2009-10-13 15:20 ` [uClinux-dev] [PATCH] NOMMU: fix malloc performance by addinguninitialized flag Robin Getz
2007-03-30 18:13 ` [PATCH] nommu arch dont zero the anonymous mapping by adding UNINITIALIZE flag Alan Cox
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