From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752933AbdI1MqF (ORCPT ); Thu, 28 Sep 2017 08:46:05 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:56319 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751906AbdI1MqE (ORCPT ); Thu, 28 Sep 2017 08:46:04 -0400 Date: Thu, 28 Sep 2017 14:45:56 +0200 (CEST) From: Thomas Gleixner To: Peter Zijlstra cc: Anna-Maria Gleixner , LKML , Ingo Molnar , Christoph Hellwig , keescook@chromium.org, John Stultz Subject: Re: [PATCH 06/25] hrtimer: Store running timer in hrtimer_clock_base In-Reply-To: <20170925144434.he26rxtkkwqvbwkg@hirez.programming.kicks-ass.net> Message-ID: References: <20170831105725.809317030@linutronix.de> <20170831105826.046126827@linutronix.de> <20170925144434.he26rxtkkwqvbwkg@hirez.programming.kicks-ass.net> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 25 Sep 2017, Peter Zijlstra wrote: > On Thu, Aug 31, 2017 at 12:23:36PM -0000, Anna-Maria Gleixner wrote: > > Unfortunately this makes cpu_clock base larger than 32 bytes on 32bit > > kernels. Instead of having huge gaps due to alignment, remove the alignment > > and let the compiler pack cpu base for 32bit. The resulting cache access > > patterns are fortunately not really different from the current > > behaviour. > > How did you determine this? Perf lacks much useful tooling right about > there :/ Just by analyzing the resulting layout and looking at the number of cache lines involved for the frequently used clocks (mono/real). Thanks, tglx