Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756678AbaGWEzK (ORCPT ); Wed, 23 Jul 2014 00:55:10 -0400 Received: from mail-we0-f182.google.com ([74.125.82.182]:47734 "EHLO mail-we0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756136AbaGWEzH (ORCPT ); Wed, 23 Jul 2014 00:55:07 -0400 Message-ID: <1406091303.5076.33.camel@marge.simpson.net> Subject: Re: [RFC PATCH 0/5] futex: introduce an optimistic spinning futex From: Mike Galbraith To: Andi Kleen Cc: Waiman Long , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Darren Hart , Davidlohr Bueso , Heiko Carstens , linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, linux-doc@vger.kernel.org, Jason Low , Scott J Norton Date: Wed, 23 Jul 2014 06:55:03 +0200 In-Reply-To: <8761iq3bp3.fsf@tassilo.jf.intel.com> References: <1405956271-34339-1-git-send-email-Waiman.Long@hp.com> <8761iq3bp3.fsf@tassilo.jf.intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2014-07-21 at 09:42 -0700, Andi Kleen wrote: > FWIW the main problem is currently that switch-through-idle is so > slow. I think improving that would give a boost to far more > situations. Two high frequency idle enter/exit suckage spots: 1) nohz (tick) - it's expensive to start/stop tick on every micro-idle, throttle it or something. 2) ondemand governor - tweak silly default settings to reflect the reality that we routinely schedule communicating threads cross core. (3. seek/destroy fastpath cycles, damn things multiply over time) -Mike -- 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/