From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263979AbUGZQyi (ORCPT ); Mon, 26 Jul 2004 12:54:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262380AbUGZQyi (ORCPT ); Mon, 26 Jul 2004 12:54:38 -0400 Received: from ss1000.ms.mff.cuni.cz ([195.113.20.8]:46977 "EHLO ss1000.ms.mff.cuni.cz") by vger.kernel.org with ESMTP id S264430AbUGZPnP (ORCPT ); Mon, 26 Jul 2004 11:43:15 -0400 Date: Mon, 26 Jul 2004 17:43:12 +0200 From: Rudo Thomas To: Ingo Molnar Cc: Lee Revell , linux-kernel Subject: Re: preempt timing violations (unmap_vmas) Message-ID: <20040726154312.GA28607@ss1000.ms.mff.cuni.cz> Mail-Followup-To: Ingo Molnar , Lee Revell , linux-kernel References: <1090813907.6936.56.camel@mindpipe> <20040726085002.GA25519@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040726085002.GA25519@elte.hu> User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hello. > > 2ms non-preemptible critical section violated 1 ms preempt threshold > > starting at unmap_vmas+0x1ff/0x210 and ending at > > unmap_vmas+0x1f5/0x210 > > this is the normal sys_exit()->exit_mmap()->unmap_vmas() path. It's > weird that it generated a 2ms latency. What are the values of > voluntary_preemption and kernel_preemption on your current kernel? With > a 2:0 setting we ought to have a reschedule point every 32 pages. Do > you know which application triggers this latency and is it easy to > reproduce? I discovered that I got two of these in a row. The settings are 2:1, but I am not able to reproduce it. Rudo.