Date: Thu, 19 Apr 2001 13:52:21 -0600 From: Warner Losh <imp@harmony.village.org> To: Poul-Henning Kamp <phk@critter.freebsd.dk> Cc: David Miller <dmiller@sparks.net>, freebsd-hackers@FreeBSD.ORG Subject: Re: [OT] parallel port for IO? Message-ID: <200104191952.f3JJqL806575@harmony.village.org> In-Reply-To: Your message of "Thu, 19 Apr 2001 21:41:57 %2B0200." <60546.987709317@critter> References: <60546.987709317@critter>
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In message <60546.987709317@critter> Poul-Henning Kamp writes: : Use the pps driver and you get microsecond jitter with nanosecond : resolution. While I usually see microsecond jitter, I have seen it as high as a few milliseconds when the interrupt load on the machine was high and the cpu was slow. I setup a system for a user here for pps (pulse per second signal), and he was quite upset to see the occasional spike in his data. Fast interrupts reduced the occurance of spikes from a few an hour to one a day. Warner To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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