From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by oss.sgi.com id ; Tue, 14 Nov 2000 15:41:51 -0800 Received: from u-210.karlsruhe.ipdial.viaginterkom.de ([62.180.18.210]:8452 "EHLO u-210.karlsruhe.ipdial.viaginterkom.de") by oss.sgi.com with ESMTP id ; Tue, 14 Nov 2000 15:41:40 -0800 Received: (ralf@lappi) by lappi.waldorf-gmbh.de id ; Wed, 15 Nov 2000 00:41:22 +0100 Date: Wed, 15 Nov 2000 00:41:22 +0100 From: Ralf Baechle To: Harald Koerfgen Cc: linux-mips@oss.sgi.com Subject: Re: Build failure for R3000 DECstation Message-ID: <20001115004122.G927@bacchus.dhis.org> References: <20001113104735.A3253@bacchus.dhis.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0.1i In-Reply-To: ; from Harald.Koerfgen@home.ivm.de on Tue, Nov 14, 2000 at 10:30:17PM +0100 X-Accept-Language: de,en,fr Sender: owner-linux-mips@oss.sgi.com Precedence: bulk Return-Path: X-Orcpt: rfc822;linux-mips-outgoing On Tue, Nov 14, 2000 at 10:30:17PM +0100, Harald Koerfgen wrote: > > Obviously none of them seemed to care so now I'm doing the quick fix. > > Frankly, a syscall which shouldn't be used doesn't deserve more attention ... > > Well, it seems as if there are people with a different opinion. Fresh from the > glibc CVS (libc/sysdeps/unix/sysv/linux/mips/sys/tas.h): I know. Otherwise I'd have plain killed this syscall rsn. > Personally I like this more than a kernel ll/sc emulation. A syscall is likely > to be faster than at least two illegal instruction exceptions. If you're > concerned about binary compatibilty, the syscall should work on ISA>=2 CPUs as > well. The idea is to punish the least widespread architecture and this are the non-ll/sc CPUs. Just like Linux is no longer performing optimally on x86. In any case, for uniprocessor non-ll/sc machines there is also a better solution availble with no syscalls at all. It's easy to implement, just use the fact that any exception will change the values of k0/k1. That of course breaks silently on SMP. glibc 2.2 calls this sysmips(). very often so optimizing them is fairly important ... Ralf