Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756763Ab2BWUDu (ORCPT ); Thu, 23 Feb 2012 15:03:50 -0500 Received: from mail-yw0-f46.google.com ([209.85.213.46]:61063 "EHLO mail-yw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756143Ab2BWUDt convert rfc822-to-8bit (ORCPT ); Thu, 23 Feb 2012 15:03:49 -0500 Authentication-Results: mr.google.com; spf=pass (google.com: domain of venki@google.com designates 10.50.222.132 as permitted sender) smtp.mail=venki@google.com; dkim=pass header.i=venki@google.com MIME-Version: 1.0 In-Reply-To: <20120223075027.GB15306@elte.hu> References: <1329957415-15239-1-git-send-email-venki@google.com> <20120223075027.GB15306@elte.hu> Date: Thu, 23 Feb 2012 12:03:48 -0800 Message-ID: Subject: Re: [PATCH] Extend mwait idle to optimize away CAL and RES interrupts to an idle CPU -v1 From: Venki Pallipadi To: Ingo Molnar Cc: Peter Zijlstra , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Suresh Siddha , Aaron Durbin , Paul Turner , Yong Zhang , linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1665 Lines: 50 [ Resending without the ugly email client formatting ] On Wed, Feb 22, 2012 at 11:50 PM, Ingo Molnar wrote: > > * Venkatesh Pallipadi wrote: > >> * Do we need some accounting for these wakeups exported for powertop? > > If then tracepoints. > >> * We can also eliminate TS_POLLING flag in favor of this. But, that will have >> ? a lot more touchpoints and better done as a standlone change. > > Should most definitely be done for this series to be acceptble - > as a preparatory patch in the series, with the feature at the > end of the series. > OK. Will look at TS_POLLING part and likely include it in the next resend. >> +DECLARE_PER_CPU(atomic_t *, idle_task_ti_flags); > > That's ugly, we should access the idle task's ti flags directly. > > To have efficient percpu access to the idle threads another > clean-up is needed: we should turn idle_thread_array into a > full-structure PER_CPU area. > > For that we need a small variant of fork_idle(), which does not > dup the init thread - pretty trivial. > > fork_idle() should also make sure it does not schedule the child > thread: thus we'd also be able to further simplify smpboot.c and > get rid of all that extremely ugly 'struct create_idle' > gymnastics in smpboot.c. > Hmm. Not being very familiar with that code, I will have to take a closer look at this potential cleanup... Thanks, Venki > Thanks, > > ? ? ? ?Ingo -- 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/