Date: Sat, 8 Nov 1997 03:13:25 -0800 From: Jonathan Mini <mini@d198-232.uoregon.edu> To: Mike Smith <mike@smith.net.au> Cc: hackers@FreeBSD.ORG Subject: Re: x86 gods; advice? Suggestions? Message-ID: <19971108031324.33689@micron.mini.net> In-Reply-To: <199711081051.VAA00966@word.smith.net.au>; from Mike Smith on Sat, Nov 08, 1997 at 09:21:50PM %2B1030 References: <19971108024958.28488@micron.mini.net> <199711081051.VAA00966@word.smith.net.au>
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Mike Smith <mike@smith.net.au> stands accused of saying: > > > Two possible solutions; use a coprocess running the vm86 thread as a > > > sort of "graphics processor" (involves a context switch between > > > operations, but you could stack them), or wait for the vm86 sysarch() > > > stuff that comes with the vm86 stuff I am working on. (Kernel entry > > > and two context switches per call.) > > > > That is how I originally planned writing the code. I am working on a method > > that uses vfork(2) to see if it is any faster/slower/doesn't-make-a-difference. > > Don't use vfork; it sucks. Use popen() and a dedicated graphics > processor process. Ok. You win. :) > Note that the FreeBSD pipe code has some odd behavioural quirks; most > particularly the more you can write in a single hit, the faster it is. > This is especially the case if you are writing a large amount of data > in a stream between processes. If you're writing from scattered > buffers, using writev() is an *enormous* win. This behaviour is not quirky at all. It makes perfect sense. > > Not much is really done in the vm86 task, just calls to do things like set the > > video mode and such. > > "And such" doesn't include anything particularly speed critical? Nope. "and such" is things like 'please return the video card back to a state that syscons wants it in' -- Jonathan Mini Ingenious Productions Software Development P.O. Box 5693, Eugene, Or. 97405 "A child of five could understand this! Quick -- Fetch me a child of five."
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