Date: Thu, 21 Oct 2010 13:54:47 +0000 From: Alexander Best <arundel@freebsd.org> To: Scott Long <scottl@samsco.org> Cc: freebsd-scsi@freebsd.org Subject: Re: set kern.cam.scsi_delay to 2000ms on all platforms Message-ID: <20101021135447.GC72290@freebsd.org> In-Reply-To: <8B967C79-CD84-435C-9007-E33467DC92A9@samsco.org> References: <20101019221131.GA75368@freebsd.org> <63EF6D51-1196-43F1-8521-27756E972263@samsco.org> <20101021062150.GA20489@freebsd.org> <8B967C79-CD84-435C-9007-E33467DC92A9@samsco.org>
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On Thu Oct 21 10, Scott Long wrote: > Ok, I've gotta be a stick in the mud and ask you how you've come to the conclusion that 2000 is better than 5000. Can you provide your evidence and/or testing results? i'm running with kern.cam.scsi_delay set to 2000 and haven't experienced any timeout issues. my original patch lowered kern.cam.scsi_delay to 5000, but after receiving some feedback on freebsd-current@ [1] i was under the impression that the majority of people responding to my post considered 5000 to be too high. Matthew Jacob e.g. wrote that even 2 seconds is more than enough even for older hardware. John Baldwin also seemed to agree with lowering the timeout value to 2 seconds. this timeout value is not intended to wait for devices to initialize upon boot time. kern.cam.boot_delay must be set in that case. it only applies to the timeout of already succussefully initialzed devices. cheers. alex [1] http://www.mail-archive.com/freebsd-hackers@freebsd.org/msg158316.html > > Scott > > On Oct 21, 2010, at 12:21 AM, Alexander Best wrote: > > > a few years ago kern.cam.scsi_delay was set from 150000 to 5000. nowadays a > > value of 2000 should be sufficient even on old/slow hardware. > > > > to have cleaner code it's better to set default value to 2000 instead of doing > > so in every config file on every platform. > > > > cheers. > > alex > > > > On Wed Oct 20 10, Scott Long wrote: > >> You've described the "what" but not the "why". Why do you want to remove this option? Why do you want to change its value? > >> > >> Scott > >> > >> On Oct 19, 2010, at 4:11 PM, Alexander Best wrote: > >> > >>> hi there, > >>> > >>> i've posted this patch on freebsd-hackers@, but jhb@ recommended i should also > >>> send it to freebsd-scsi@. basically what this patch does is to populate > >>> kern.cam.scsi_delay=2000 as the default value throughout the entire source > >>> tree. in addition to that it gets rid of some legacy Makefile entries, where > >>> kern.cam.scsi_delay was set to 150000. > >>> > >>> cheers. > >>> alex > >>> > >>> -- > >>> a13x > >>> <SCSI_DELAY.diff2>_______________________________________________ > >>> freebsd-scsi@freebsd.org mailing list > >>> http://lists.freebsd.org/mailman/listinfo/freebsd-scsi > >>> To unsubscribe, send any mail to "freebsd-scsi-unsubscribe@freebsd.org" > > > > -- > > a13x -- a13x
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