Date: Tue, 18 Apr 1995 09:57:01 +0200 (MET DST) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: julian@ref.tfs.com (Julian Elischer) Cc: chitra@CS.SunySB.EDU, freebsd-hackers@FreeBSD.org Subject: Re: help with timeouts Message-ID: <199504180757.JAA13088@labinfo.iet.unipi.it> In-Reply-To: <199504180639.XAA02115@ref.tfs.com> from "Julian Elischer" at Apr 17, 95 11:38:41 pm
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> > Hi! > > I am developing a token bus protocol in the FreeBSD network > > interrupt handler. For the > > token recovery algorithm that I have, I need to set microsecond > > timeouts (they could be off by upto 500 u_sec and still serve my purpose). > > As things are now, I can only set timeouts in multiples of 10 millisec. > > Can you please tell me how I can implement u_sec timeouts ? > > Any help will be much appreciated. > > There is already code that 'turns up' the system clock frequency > (I believe the pc-audio code to be exact) to (I think) 10KHz > so you could do similar and get 100uSec time, pcaudio runs at 16 KHz, I think. This means one interrupt every 62.5 uS; this is *not* something you want to run continuously on your system: the overhead is high, some interrupts are missed, even on my 486/66, and you see you clock slowing down (due to the missed interrupts). Luigi ==================================================================== Luigi Rizzo Dip. di Ingegneria dell'Informazione email: luigi@iet.unipi.it Universita' di Pisa tel: +39-50-568533 via Diotisalvi 2, 56126 PISA (Italy) fax: +39-50-568522 ====================================================================
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