Subject: Re: Interrupt, interrupt threads, continuations, and kernel lwps
To: NetBSD Kernel Technical Discussion List <>
From: Greg A. Woods <>
List: tech-kern
Date: 02/23/2007 15:17:51
At Fri, 23 Feb 2007 08:51:36 -0800, wrote:
> I think we *need* to do that, to continue good performance on machines
> where the full switch is prohibitive.  If we collectively buy that,
> then that decision drives us into a "top half" / "bottom half" model.


On a perhaps slightly related note, and at the risk of comparing apples
and oranges, I was trying FreeBSD-6.2 on my PE2650 to see if it had any
better luck seeing both the built-in PERC and the add-on HP NetRAID
controllers I have on it.  I'm not sure what the results were there yet,
as I had a power failure in the middle of my test last night.  However I
did have time to observe that on a plain raw read of the ld0d device the
FreeBSD aac(4) driver achieved a rate nearly twice that of the NetBSD
driver.  The FreeBSD driver is, if I understand correctly, split into a
top/bottom model already, with the top half running in a kernel thread.

						Greg A. Woods

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