From owner-freebsd-current Mon Feb 15 04:14:01 1999 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id EAA26073 for freebsd-current-outgoing; Mon, 15 Feb 1999 04:14:01 -0800 (PST) (envelope-from owner-freebsd-current@FreeBSD.ORG) Received: from hda.hda.com (hda-bicnet.bicnet.net [209.244.238.132] (may be forged)) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id EAA26053 for ; Mon, 15 Feb 1999 04:13:56 -0800 (PST) (envelope-from dufault@hda.hda.com) Received: (from dufault@localhost) by hda.hda.com (8.8.5/8.8.5) id HAA05524; Mon, 15 Feb 1999 07:06:12 -0500 (EST) From: Peter Dufault Message-Id: <199902151206.HAA05524@hda.hda.com> Subject: Re: Weird piecemeal reads over socketpair() pipe breaks up small writes into even smaller reads. In-Reply-To: <199902150619.RAA24136@godzilla.zeta.org.au> from Bruce Evans at "Feb 15, 99 05:19:12 pm" To: bde@zeta.org.au (Bruce Evans) Date: Mon, 15 Feb 1999 07:06:11 -0500 (EST) Cc: dillon@apollo.backplane.com, freebsd-current@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL25 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > When the writer blocks, the reader runs and uses a buggy loop to read > only the first chunk of input. > > On an otherwise idle system, the need_resched() condition seems to be > true always. I would have expected the synchronisation provided by the > sleep(1) to bias need_resched() in the opposite direction. A reschedule > has been done, normally just after the previous hardclock() call, just > before the writer wakes up, so another one should not be done soon > (until after the next hardclock() call). Sorry everyone, I'll be away for a week and won't put in my scheduler fixes until I get back. Most of the changes are on Freefall in my home directory. I hate to be so passive about committing tested code, but my schedule is such over the last few months that I'm never around to fix things up if the unexpected happens. I'm working hard on a proposal that will let me spend some quality time on this - wish me luck. Meanwhile, I'm off all the lists. I'll check e-mail sent to either dufault@hda.com or dufault@freebsd.org intermittently. Peter -- Peter Dufault (dufault@hda.com) Realtime development, Machine control, HD Associates, Inc. Safety critical systems, Agency approval To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message