Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756543Ab2BGBZC (ORCPT ); Mon, 6 Feb 2012 20:25:02 -0500 Received: from terminus.zytor.com ([198.137.202.10]:34093 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755883Ab2BGBZA (ORCPT ); Mon, 6 Feb 2012 20:25:00 -0500 Message-ID: <4F307D45.1050404@zytor.com> Date: Mon, 06 Feb 2012 17:24:21 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:9.0) Gecko/20111222 Thunderbird/9.0 MIME-Version: 1.0 To: David Daney CC: Venkatesh Pallipadi , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Suresh Siddha , Aaron Durbin , Paul Turner , linux-kernel@vger.kernel.org Subject: Re: [RFC] Extend mwait idle to optimize away IPIs when possible References: <1328560933-3037-1-git-send-email-venki@google.com> <4F306FAF.7020500@cavium.com> In-Reply-To: <4F306FAF.7020500@cavium.com> X-Enigmail-Version: 1.3.4 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1381 Lines: 53 On 02/06/2012 04:26 PM, David Daney wrote: > On 02/06/2012 12:42 PM, Venkatesh Pallipadi wrote: > [...] >> index 5bed94e..6a56cb0 100644 >> --- a/arch/x86/Kconfig >> +++ b/arch/x86/Kconfig >> @@ -170,6 +170,11 @@ config GENERIC_TIME_VSYSCALL >> bool >> default X86_64 >> >> +config AVOID_IPI_ON_IDLE >> + bool >> + depends on X86_64 >> + default X86_64 >> + > > Can you get rid of this part... > >> config ARCH_HAS_CPU_RELAX >> def_bool y >> > [...] >> diff --git a/arch/x86/kernel/acpi/cstate.c >> b/arch/x86/kernel/acpi/cstate.c >> index f50e7fb..340c4e9 100644 >> --- a/arch/x86/kernel/acpi/cstate.c >> +++ b/arch/x86/kernel/acpi/cstate.c >> @@ -161,6 +161,14 @@ EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe); >> */ >> void mwait_idle_with_hints(unsigned long ax, unsigned long cx) >> { >> +#ifdef CONFIG_AVOID_IPI_ON_IDLE > > > ... and change all of these to #ifdef CONFIG_64BIT > >> + int oldval, cpu = smp_processor_id(); >> + Why should this be 64-bit specific?? -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/