From mboxrd@z Thu Jan 1 00:00:00 1970 Path: main.gmane.org!not-for-mail From: David Kastrup Newsgroups: gmane.emacs.devel Subject: Re: Fix for slow process output processing (please test). Date: 05 Jan 2004 23:50:36 +0100 Sender: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Message-ID: References: <87y8so7kjy.fsf@offby1.atm01.sea.blarg.net> NNTP-Posting-Host: deer.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: sea.gmane.org 1073343743 25088 80.91.224.253 (5 Jan 2004 23:02:23 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Mon, 5 Jan 2004 23:02:23 +0000 (UTC) Cc: Eric Hanchrow , emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Tue Jan 06 00:02:09 2004 Return-path: Original-Received: from quimby.gnus.org ([80.91.224.244]) by deer.gmane.org with esmtp (Exim 3.35 #1 (Debian)) id 1Addjd-0005Ni-00 for ; Tue, 06 Jan 2004 00:02:09 +0100 Original-Received: from monty-python.gnu.org ([199.232.76.173]) by quimby.gnus.org with esmtp (Exim 3.35 #1 (Debian)) id 1Addjc-0007il-00 for ; Tue, 06 Jan 2004 00:02:09 +0100 Original-Received: from localhost ([127.0.0.1] helo=monty-python.gnu.org) by monty-python.gnu.org with esmtp (Exim 4.24) id 1Adecg-0002bx-E5 for emacs-devel@quimby.gnus.org; Mon, 05 Jan 2004 18:59:02 -0500 Original-Received: from list by monty-python.gnu.org with tmda-scanned (Exim 4.24) id 1Adeac-0001m5-BT for emacs-devel@gnu.org; Mon, 05 Jan 2004 18:56:54 -0500 Original-Received: from mail by monty-python.gnu.org with spam-scanned (Exim 4.24) id 1Adea4-0001YV-SE for emacs-devel@gnu.org; Mon, 05 Jan 2004 18:56:52 -0500 Original-Received: from [199.232.41.8] (helo=mx20.gnu.org) by monty-python.gnu.org with esmtp (TLSv1:DES-CBC3-SHA:168) (Exim 4.24) id 1AdeY3-0000gN-4a for emacs-devel@gnu.org; Mon, 05 Jan 2004 18:54:15 -0500 Original-Received: from [217.80.157.161] (helo=localhost.localdomain) by mx20.gnu.org with esmtp (Exim 4.24) id 1AddZ6-0001aA-8M for emacs-devel@gnu.org; Mon, 05 Jan 2004 17:51:16 -0500 Original-Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by localhost.localdomain (8.12.8/8.12.8) with ESMTP id i05Mof88010500 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 5 Jan 2004 23:50:41 +0100 Original-Received: (from dak@localhost) by localhost.localdomain (8.12.8/8.12.8/Submit) id i05MoadC010496; Mon, 5 Jan 2004 23:50:36 +0100 Original-To: storm@cua.dk (Kim F. Storm) In-Reply-To: Original-Lines: 26 User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3.50 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.2 Precedence: list List-Id: Emacs development discussions. List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Xref: main.gmane.org gmane.emacs.devel:19025 X-Report-Spam: http://spam.gmane.org/gmane.emacs.devel:19025 storm@cua.dk (Kim F. Storm) writes: > David Kastrup writes: > > > storm@cua.dk (Kim F. Storm) writes: > > > > > I suppose that process-adaptive-read-buffering isn't really needed > > > on Windows, > > > > Since Windows is slow, anyway? > > Because the purpose of my patch was to fix a problem reported to be > specific for recent Linux kernels. Not just recent ones. They may have parameters acerbating the problem, but it has always been there. IIRC, the same effect was reported from FreeBSD; and I think it likely that almost all operating systems that proud themselves on high throughput and good interactivity and fast context switches will suffer from the same phenomenon when running on single processor machines, as long as they are able to reschedule the moment input arrives in a pipe. You need pretty wild scheduler strategies (like "anticipative scheduling") in order to avoid this effect. -- David Kastrup, Kriemhildstr. 15, 44793 Bochum