From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261552AbVGWHOZ (ORCPT ); Sat, 23 Jul 2005 03:14:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261657AbVGWHOY (ORCPT ); Sat, 23 Jul 2005 03:14:24 -0400 Received: from siaag2ag.compuserve.com ([149.174.40.140]:13530 "EHLO siaag2ag.compuserve.com") by vger.kernel.org with ESMTP id S261552AbVGWHOE (ORCPT ); Sat, 23 Jul 2005 03:14:04 -0400 Date: Sat, 23 Jul 2005 03:09:25 -0400 From: Chuck Ebbert <76306.1226@compuserve.com> Subject: Re: [patch 2.6.13-rc3a] i386: inline restore_fpu To: Andrew Morton Cc: torvalds@osdl.org, linux-kernel@vger.kernel.org, Arjan van de Ven , Adrian Bunk Message-ID: <200507230313_MC3-1-A554-6927@compuserve.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 22 Jul 2005 at 13:27:56 +1000, Andrew Morton wrote: > Chuck Ebbert <76306.1226@compuserve.com> wrote: > > After: > > > > 12534 math_state_restore 130.5625 > > 8354 device_not_available 203.7561 > > ----- > > 20888 > > Next step should be to physically place math_state_restore() after > > device_not_available(). Would such a patch be accepted? (Yes it > > would be ugly and require linker script changes.) > > Depends on the benefit/ugly ratio ;) This patch (may not apply cleanly to unpatched -rc3) drops overhead a few more percent: 11835 math_state_restore 144.3293 8096 device_not_available 197.4634 ----- 19931 Most of the exception/interrupt handlers should get the same treatment but the linker script would grow. Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Index: 2.6.13-rc3a/arch/i386/kernel/entry.S =================================================================== --- 2.6.13-rc3a.orig/arch/i386/kernel/entry.S 2005-07-16 18:09:48.000000000 -0400 +++ 2.6.13-rc3a/arch/i386/kernel/entry.S 2005-07-22 05:19:22.000000000 -0400 @@ -469,6 +469,7 @@ pushl $do_simd_coprocessor_error jmp error_code + .section ".text.i387_1", "a" ENTRY(device_not_available) pushl $-1 # mark this as an int SAVE_ALL @@ -484,6 +485,8 @@ addl $4, %esp jmp ret_from_exception + .previous + /* * Debug traps and NMI can happen at the one SYSENTER instruction * that sets up the real kernel stack. Check here, since we can't Index: 2.6.13-rc3a/arch/i386/kernel/traps.c =================================================================== --- 2.6.13-rc3a.orig/arch/i386/kernel/traps.c 2005-07-16 18:05:40.000000000 -0400 +++ 2.6.13-rc3a/arch/i386/kernel/traps.c 2005-07-22 14:02:50.000000000 -0400 @@ -972,7 +972,8 @@ * Must be called with kernel preemption disabled (in this case, * local interrupts are disabled at the call-site in entry.S). */ -asmlinkage void math_state_restore(struct pt_regs regs) +asmlinkage void __attribute__((__section__(".text.i387_2"))) +math_state_restore(struct pt_regs regs) { struct thread_info *thread = current_thread_info(); struct task_struct *tsk = thread->task; Index: 2.6.13-rc3a/arch/i386/kernel/vmlinux.lds.S =================================================================== --- 2.6.13-rc3a.orig/arch/i386/kernel/vmlinux.lds.S 2005-07-16 18:05:39.000000000 -0400 +++ 2.6.13-rc3a/arch/i386/kernel/vmlinux.lds.S 2005-07-22 05:20:30.000000000 -0400 @@ -20,6 +20,8 @@ _text = .; /* Text and read-only data */ .text : AT(ADDR(.text) - LOAD_OFFSET) { *(.text) + *(.text.i387_1) + *(.text.i387_2) SCHED_TEXT LOCK_TEXT *(.fixup) __ Chuck