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Re: PATCH: Always use ll/sc for mips
- From: "H. J. Lu" <hjl at lucon dot org>
- To: Ralf Baechle <ralf at oss dot sgi dot com>
- Cc: linux-mips at oss dot sgi dot com,GNU C Library <libc-alpha at sources dot redhat dot com>
- Date: Tue, 2 Jul 2002 14:04:51 -0700
- Subject: Re: PATCH: Always use ll/sc for mips
- References: <20020702114045.A16197@lucon.org> <20020702220651.B9566@dea.linux-mips.net>
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.