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Re: PATCH: Always use ll/sc for mips

To: Ralf Baechle <ralf@oss.sgi.com>
Subject: Re: PATCH: Always use ll/sc for mips
From: "H. J. Lu" <hjl@lucon.org>
Date: Tue, 2 Jul 2002 14:04:51 -0700
Cc: linux-mips@oss.sgi.com, GNU C Library <libc-alpha@sources.redhat.com>
In-reply-to: <20020702220651.B9566@dea.linux-mips.net>; from ralf@oss.sgi.com on Tue, Jul 02, 2002 at 10:06:51PM +0200
References: <20020702114045.A16197@lucon.org> <20020702220651.B9566@dea.linux-mips.net>
Sender: owner-linux-mips@oss.sgi.com
User-agent: Mutt/1.2.5.1i
On Tue, Jul 02, 2002 at 10:06:51PM +0200, Ralf Baechle wrote:
> On Tue, Jul 02, 2002 at 11:40:45AM -0700, H. J. Lu wrote:
> 
> > The ll/sc emulation is implemented in 2.4.0 and above. This patch makes
> > glibc always use ll/sc.
> 
> Which means the overhead of two syscalls instead of one sysmips() call
> for something that is assumed to be dirt cheap.  R3000, R5900 etc.
> users won't this patch you, which'll have significant impact on their
> glibc performance.
> 

Not all ll/sc usages are implemented with sysmips. Does mips care about
those? In case of libstdc++, should mips use ll/sc emulation?


H.J.


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