From owner-freebsd-current Tue Mar 21 13:38:29 2000 Delivered-To: freebsd-current@freebsd.org Received: from mass.cdrom.com (mg130-183.ricochet.net [204.179.130.183]) by hub.freebsd.org (Postfix) with ESMTP id 606FB37B881 for ; Tue, 21 Mar 2000 13:38:24 -0800 (PST) (envelope-from msmith@mass.cdrom.com) Received: from mass.cdrom.com (localhost [127.0.0.1]) by mass.cdrom.com (8.9.3/8.9.3) with ESMTP id NAA00925; Tue, 21 Mar 2000 13:40:20 -0800 (PST) (envelope-from msmith@mass.cdrom.com) Message-Id: <200003212140.NAA00925@mass.cdrom.com> X-Mailer: exmh version 2.1.1 10/15/1999 To: Matthew Dillon Cc: Brad Knowles , "John W. DeBoskey" , freebsd-current@FreeBSD.ORG, Brad Chisholm Subject: Re: AMI MegaRAID lockup? not accepting commands. In-reply-to: Your message of "Tue, 21 Mar 2000 09:14:14 PST." <200003211714.JAA81010@apollo.backplane.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Tue, 21 Mar 2000 13:40:20 -0800 From: Mike Smith Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > :At 7:25 PM -0800 2000/3/20, Mike Smith wrote: > : > :> Not that I consider this particuarly optimal; busy-waiting for the > :> controller is a terrible waste of the host CPU. A better solution would > :> probably defer the command and try again a short time later, but let's > :> see if this works first. > : > : Since this is a device driver, I guess you can't usleep() and > :then check again? Is there anything else useful you could be doing > :during that period of time -- other than busy waiting? > > For situations that aren't in the critical path and don't happen often, > it may be beneficial to do a voluntary context switch inside the loop. Is it possible/legal to do this inside a strategy() routine? -- \\ Give a man a fish, and you feed him for a day. \\ Mike Smith \\ Tell him he should learn how to fish himself, \\ msmith@freebsd.org \\ and he'll hate you for a lifetime. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message