From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935456AbXGQUi2 (ORCPT ); Tue, 17 Jul 2007 16:38:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755773AbXGQUiU (ORCPT ); Tue, 17 Jul 2007 16:38:20 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:50533 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754329AbXGQUiT (ORCPT ); Tue, 17 Jul 2007 16:38:19 -0400 Date: Tue, 17 Jul 2007 13:37:16 -0700 (PDT) From: Linus Torvalds To: Ingo Molnar cc: Markus , Linux Kernel Mailing List , Andrew Morton , Mike Galbraith , Arjan van de Ven , Thomas Gleixner , Dmitry Adamushko , Srivatsa Vaddagiri , Alan Cox Subject: Re: [patch] CFS scheduler, -v19 In-Reply-To: <20070717200929.GA2426@elte.hu> Message-ID: References: <20070706173319.GA2356@elte.hu> <200707171506.37886.lists4me@web.de> <20070717170628.GA6002@elte.hu> <200707172142.42008.lists4me@web.de> <20070717200929.GA2426@elte.hu> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 17 Jul 2007, Ingo Molnar wrote: > > i think the problem starts here: > > 11902 1184699865.141939 read(3, "", 32) = 0 <0.000007> Well, it's preceded by a poll() that says that it has a POLLHUP event, so that socket would seem to have simply been closed from the other end. There's also a huge amount of select() calls showing the same thing (except since it's just the input side, you cannot tell that it's POLLHUP). Don't ask me *why*, though. It's preceded by .. 11902 1184699848.615201 read(3, 0x7fffb5b9c8b0, 32) = -1 EAGAIN (Resource temporarily unavailable) <0.000009> 11902 1184699848.615252 poll([{fd=3, events=POLLIN, revents=POLLIN}], 1, -1) = 1 <0.009307> 11902 1184699848.624614 read(3, "\1 \303!\0\0\0\0\4\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0b\340T\0\0\0\0\0", 32) = 32 <0.000011> .. got data .. 11902 1184699848.624710 ioctl(3, FIONREAD, [0]) = 0 <0.000009> 11902 1184699848.624762 ioctl(3, FIONREAD, [0]) = 0 <0.000048> .. ok, nothing more.. 11902 1184699848.624866 select(10, [3 4 5 7 9], [], [], NULL) = 1 (in [3]) <16.495008> 11902 1184699865.119950 ioctl(3, FIONREAD, [0]) = 0 <0.000006> 16+ seconds pass, now it's marked as readable, but returns zero bytes of data: the other end closed it. Tons of unnecessary and stupid sequences of: 11902 1184699865.119988 select(10, [3 4 5 7 9], [], [], NULL) = 1 (in [3]) <0.000007> 11902 1184699865.120031 ioctl(3, FIONREAD, [0]) = 0 <0.000005> .. and then finally: ... 11902 1184699865.141809 poll([{fd=3, events=POLLIN, revents=POLLIN|POLLHUP}], 1, 0) = 1 <0.000005> 11902 1184699865.141838 ioctl(3, FIONREAD, [0]) = 0 <0.000005> 11902 1184699865.141939 read(3, "", 32) = 0 <0.000007> ie now konqueror noticed that it was *really* closed, and read the EOF. But why does that happen? And why would the scheduler have *anything* to do with this? No idea. Maybe timing. Maybe the time.c changes. Dunno. Linus