Re: PATCH: Re: Inefficient ia64 system call implementation in glibc

From: H. J. Lu <hjl_at_lucon.org>
Date: 2003-09-25 14:39:29
On Wed, Sep 24, 2003 at 09:43:19AM +0200, Jakub Jelinek wrote:
> On Wed, Sep 24, 2003 at 10:36:21AM +0200, Andreas Schwab wrote:
> > >> x+0 would work in this case; I'd guess it'd work for most of the
> > >> cases that syscalls need to handle.
> > >> 
> > >
> > > This patch works for me.
> > >
> > >
> > > H.J.
> > > ---
> > > 2003-09-22  H.J. Lu  <hongjiu.lu@intel.com>
> > >
> > > 	* sysdeps/unix/sysv/linux/ia64/sysdep.h (LOAD_ARGS_1): Use
> > > 	__typeof ((outX) + 0) instead of long.
> > 
> > Hopefully we don't have any occurences of LOAD_ARGS_n(...,0,..) where the
> > kernel expects long.
> 
> I think that's very risky and could mean hard to find bugs.
> I don't think the 0-1 cycle speedup is not worth the troubles.

I don't think it is any riskier than using long. Those are internal
to libc. We don't have to worry about any users will misuse them. We
just have to make sure we pass the right types of arguments to kernel
in glibc. I don't think it is too much to ask.


H.J.
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Received on Thu Sep 25 00:39:42 2003

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