Date: Fri, 09 Mar 2001 14:10:21 -0800 From: Mike Smith <msmith@freebsd.org> To: Joe Albowicz <joe@CS.UCLA.EDU> Cc: freebsd-hackers@freebsd.org Subject: Re: aic7xxx driver & SCBs Message-ID: <200103092210.f29MALs09079@mass.dis.org> In-Reply-To: Your message of "Fri, 09 Mar 2001 13:55:56 PST." <Pine.SOL.4.33.0103091318390.11005-100000@panther.cs.ucla.edu>
next in thread | previous in thread | raw e-mail | index | archive | help
Joe; it looks like you have some funny ideas about something that's not
actually very relevant. I assume that you have already gone and bought
Monster Cable(tm) SCSI cables, and that you have the special
oxygen-free-copper SCSI controller PCBs, because none of this is going to
mean anything unless you have.
> I'd like to ask if anyone can share any knowledge about how/if the number
> of SCBs affects performace for scsi drives.
If you don't have enough SCBs, you can't deliver enough commands to your
drive(s) to keep them busy.
> Also I would like to be able to configure the number of SCBs that the scsi
> driver uses. With Linux this parameter for the aic7xxx driver can be
> configured via "make menuconfig" step of the kernel build process. Is
> there a similiar way to configure this varible for BSD? Or do I have to
> start hacking on the driver code?
You can't do that. Firstly, there isn't a "SCSI driver", secondly there
are several different sorts of objects that map to what you, coming from
the Linux world, would call an SCB, and thirdly, the CAM subsystem
components have a much better idea than you do how many of these that are
needed, and will allocate them as necessary.
--
... every activity meets with opposition, everyone who acts has his
rivals and unfortunately opponents also. But not because people want
to be opponents, rather because the tasks and relationships force
people to take different points of view. [Dr. Fritz Todt]
V I C T O R Y N O T V E N G E A N C E
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200103092210.f29MALs09079>