Date: Tue, 21 Mar 2000 13:40:20 -0800 From: Mike Smith <msmith@freebsd.org> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: Brad Knowles <blk@skynet.be>, "John W. DeBoskey" <jwd@unx.sas.com>, freebsd-current@FreeBSD.ORG, Brad Chisholm <sasblc@unx.sas.com> Subject: Re: AMI MegaRAID lockup? not accepting commands. Message-ID: <200003212140.NAA00925@mass.cdrom.com> In-Reply-To: Your message of "Tue, 21 Mar 2000 09:14:14 PST." <200003211714.JAA81010@apollo.backplane.com>
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> :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
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