Messages in this thread | | | Subject | RE: cciss updates for 2.6.6xxx [1/2] | Date | Wed, 7 Apr 2004 11:21:47 -0500 | From | "Miller, Mike (OS Dev)" <> |
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Yep, you're right. I just regurgitated the same code. I'll pull my head out and try again :(
mikem
-----Original Message----- From: Jeff Garzik [mailto:jgarzik@pobox.com] Sent: Wednesday, April 07, 2004 11:15 AM To: Miller, Mike (OS Dev) Cc: alpm@odsl.org; axboe@suse.de; linux-kernel@vger.kernel.org Subject: Re: cciss updates for 2.6.6xxx [1/2]
mikem@beardog.cca.cpqcorp.net wrote: > This patch adds per logical device queues to the HP cciss driver. It currently only implements a single lock but when time permits I will provide that funtionality. Thanks to Jeff Garzik for providing some sample code. > This patch built against 2.6.5. Please consider this for inclusion.
I appreciate the credit but I don't see that it addressed my original objection -- the starvation issue.
Do you cap the number of per-array requests a "1024 / n_arrays", or something like that? You mentioned that the hardware has a maximum of 1024 outstanding commands, for all devices. The two typical solutions are a round-robin queue (see carmel.c) or limiting each array such that if all arrays are full of commands, the total outstanding never exceeds 1024.
This patch may be OK for -mm, I would rather not see it go upstream -- it seems to me you are choosing to decrease stability to obtain a performance increase. I think you can increase performance without decreasing stability.
Jeff
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