From owner-freebsd-smp Fri Jan 21 5: 8:31 2000 Delivered-To: freebsd-smp@freebsd.org Received: from mail.nyct.net (bsd4.nyct.net [204.141.86.6]) by hub.freebsd.org (Postfix) with ESMTP id 3FFD914D42; Fri, 21 Jan 2000 05:08:27 -0800 (PST) (envelope-from mbac@nyct.net) Received: from bsd1.nyct.net (mbac@bsd1.nyct.net [204.141.86.3]) by mail.nyct.net (8.8.8/8.8.7) with ESMTP id IAA21367; Fri, 21 Jan 2000 08:08:26 -0500 (EST) (envelope-from mbac@nyct.net) Received: from localhost (mbac@localhost) by bsd1.nyct.net (8.8.8/8.9.3) with ESMTP id IAA06755; Fri, 21 Jan 2000 08:08:26 -0500 (EST) (envelope-from mbac@nyct.net) X-Authentication-Warning: bsd1.nyct.net: mbac owned process doing -bs Date: Fri, 21 Jan 2000 08:08:26 -0500 (EST) From: Michael Bacarella To: Seigo Tanimura Cc: smp@FreeBSD.ORG, hackers@FreeBSD.ORG Subject: Re: Using spinning time efficiently? In-Reply-To: <14472.10247.374655.13283E@rina.r.dl.itc.u-tokyo.ac.jp> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-smp@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > I once thought something might be wrong, and then found > (ALT)SYSCALL_LOCK spinning to wait for the lock to be released. Now I > am wondering if we can contribute spinning time to anything else, say > running another process, before the lock gets released. Is is possible > to do so? I'm the last person who you'd speak to for an authoritative answer to a FreeBSD question, but I'll try fielding it. What version of FreeBSD? Your kernel might be spinlocking other processes out because the kernel isn't totally re-entrant. Yet. Version number here might be significant. At least, this is the only reason I can think of for spinlocking away at syscall entry. In such a case, recognizing this situation and then just deciding to run another process instead of spinning away helplessly wouldn't do much good. To run another process, it'd need to enter the kernel and select one. That's still the same problem. -MB To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message