Date: Wed, 30 Aug 2006 13:23:26 -0400 (EDT) From: Andrew Gallatin <gallatin@cs.duke.edu> To: "Jack Vogel" <jfvogel@gmail.com> Cc: freebsd-net <freebsd-net@freebsd.org>, Alan Cox <alc@cs.rice.edu>, freebsd-current <freebsd-current@freebsd.org>, Mohan Srinivasan <mohan_srinivasan@yahoo.com>, Robert Watson <rwatson@freebsd.org> Subject: Re: RFC: FreeBSD I/OAT driver Message-ID: <17653.51598.910897.127606@grasshopper.cs.duke.edu> In-Reply-To: <2a41acea0608291624u4ee91cdej2d87aa19e2e5ba62@mail.gmail.com> References: <2a41acea0608291624u4ee91cdej2d87aa19e2e5ba62@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Jack Vogel writes: > We are making our development driver for the I/OAT engine available for > download, experimentation, and comment available at: > > http://sourceforge.net/project/showfiles.php?group_id=42302&package_id=202220 > > This includes a core driver for the dma hardware and a set of stack changes > to allow use of the engine on the receive side of the stack. > > There are certainly rough edges and limitations in this code, but we have run > it internally and seen some great results. > > I would like to see this get into CURRENT, so anything Prafulla and I can do > to help or answer questions, send us email. Excellent! Can you share some of these results? I would love to try it, but I don't have FreeBSD on any machine with I/OAT hardware. I've taken a very quick look at it. Maybe I'm just being dense, but I don't like the name "dma_" being in the global namespace. Maybe things (like dma_*_list should be called at least dmaengine_*_list, etc. There are some style(9) defects which I'm sure others who are more proficient at style(9) than I am will point out (// comments, function names not starting in column 0, etc). How deep would you expect so->dma_wait_queue to get? Would it make sense to keep a pointer to the last item so that insertion is O(1), rather than O(N)? Would it be possible to have a sysctl tunable threshold, below which the system does a normal uiomove? A normal copyout() will certainly be faster at some point.. Thanks for the great work! Drew
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?17653.51598.910897.127606>