From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755664AbZJTHJL (ORCPT ); Tue, 20 Oct 2009 03:09:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755130AbZJTHJJ (ORCPT ); Tue, 20 Oct 2009 03:09:09 -0400 Received: from vpn.id2.novell.com ([195.33.99.129]:16926 "EHLO vpn.id2.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752785AbZJTHJJ convert rfc822-to-8bit (ORCPT ); Tue, 20 Oct 2009 03:09:09 -0400 Message-Id: <4ADD7E6C020000780001AD73@vpn.id2.novell.com> X-Mailer: Novell GroupWise Internet Agent 8.0.1 Date: Tue, 20 Oct 2009 08:10:04 +0100 From: "Jan Beulich" To: , , Cc: Subject: [PATCH] x86-64: adjust ia32entry branches for better static prediction Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Swap branch pairs so that the static branch prediction logic would consider the syscall-number-in-range case the taken path. Signed-off-by: Jan Beulich --- arch/x86/ia32/ia32entry.S | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) --- linux-2.6.32-rc5/arch/x86/ia32/ia32entry.S 2009-10-19 13:12:43.000000000 +0200 +++ 2.6.32-rc5-x86_64-ia32-syscall-trace-branch-dir/arch/x86/ia32/ia32entry.S 2009-10-19 09:36:39.000000000 +0200 @@ -249,9 +249,9 @@ sysenter_tracesys: call syscall_trace_enter LOAD_ARGS32 ARGOFFSET /* reload args from stack in case ptrace changed it */ RESTORE_REST - cmpl $(IA32_NR_syscalls-1),%eax - ja int_ret_from_sys_call /* sysenter_tracesys has set RAX(%rsp) */ - jmp sysenter_do_call + cmpl $IA32_NR_syscalls,%eax + jb sysenter_do_call + jmp int_ret_from_sys_call /* sysenter_tracesys has set RAX(%rsp) */ CFI_ENDPROC ENDPROC(ia32_sysenter_target) @@ -368,9 +368,9 @@ cstar_tracesys: LOAD_ARGS32 ARGOFFSET, 1 /* reload args from stack in case ptrace changed it */ RESTORE_REST xchgl %ebp,%r9d - cmpl $(IA32_NR_syscalls-1),%eax - ja int_ret_from_sys_call /* cstar_tracesys has set RAX(%rsp) */ - jmp cstar_do_call + cmpl $IA32_NR_syscalls,%eax + jb cstar_do_call + jmp int_ret_from_sys_call /* cstar_tracesys has set RAX(%rsp) */ END(ia32_cstar_target) ia32_badarg: @@ -445,9 +445,9 @@ ia32_tracesys: call syscall_trace_enter LOAD_ARGS32 ARGOFFSET /* reload args from stack in case ptrace changed it */ RESTORE_REST - cmpl $(IA32_NR_syscalls-1),%eax - ja int_ret_from_sys_call /* ia32_tracesys has set RAX(%rsp) */ - jmp ia32_do_call + cmpl $IA32_NR_syscalls,%eax + jb ia32_do_call + jmp int_ret_from_sys_call /* ia32_tracesys has set RAX(%rsp) */ END(ia32_syscall) ia32_badsys: