Date: Mon, 17 May 2010 15:58:50 -0700 From: Oleksandr Tymoshenko <gonzo@bluezbox.com> To: Sam Leffler <sam@errno.com> Cc: freebsd-hackers@freebsd.org Subject: Re: hifn(4) DMA fix for review Message-ID: <ACFC9169-B235-4F4F-8501-1EAF307BE1BA@bluezbox.com> In-Reply-To: <892C86B0-81B0-433D-BF9C-7CDBD479F6CC@errno.com> References: <4BE46650.7010008@bluezbox.com> <892C86B0-81B0-433D-BF9C-7CDBD479F6CC@errno.com>
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On 2010-05-10, at 8:23 AM, Sam Leffler wrote: >=20 > On May 7, 2010, at 12:13 PM, Oleksandr Tymoshenko wrote: >=20 >> Proposed patch addresses hifn(4) problems on FreeBSD/mips. Current >> implementation keeps some of the state information (indexes in >> buffers, etc) in DMA-mapped memory and bus_dma code invalidates them >> during sync operations. This fix moves data that doesn't belong to = DMA >> ring to softc structure. >>=20 >> Patch: http://people.freebsd.org/~gonzo/hifn.diff >> Stats for original driver: >> http://people.freebsd.org/~gonzo/hifn.stats.orig.txt >> Stats for patched version: >> http://people.freebsd.org/~gonzo/hifn.stats.patched.txt >>=20 >>=20 >=20 > The changes look fine and make sense (did something similar for some = other drivers for when the dma data structures were mapped uncached). I = can't see any performance change in your stats; but I'm just eyeballing = the numbers side-by-side. Was this on x86? (where there should be zero = difference) It would be good to present these numbers better (e.g. = curves on the same graph, ministat output, etc). I took some time to learn gnuplot and here is result: http://people.freebsd.org/~gonzo/hifn-cmp.png The red ones are data from original driver, the blue ones are patched. = There are some=20 fluctuations but I think they're OK. I made three measurements for = original drivers and=20 there are fluctuations too with comparable order of magnitude: http://people.freebsd.org/~gonzo/hifn-orig.png=20 If it's OK - I'll commit fixes --=20 gonzo
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