From owner-freebsd-hackers Thu Apr 19 12:52:51 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from harmony.village.org (rover.bsdimp.com [204.144.255.66]) by hub.freebsd.org (Postfix) with ESMTP id 94BFC37B424 for ; Thu, 19 Apr 2001 12:52:32 -0700 (PDT) (envelope-from imp@harmony.village.org) Received: from harmony.village.org (localhost.village.org [127.0.0.1]) by harmony.village.org (8.11.3/8.11.1) with ESMTP id f3JJqL806575; Thu, 19 Apr 2001 13:52:21 -0600 (MDT) (envelope-from imp@harmony.village.org) Message-Id: <200104191952.f3JJqL806575@harmony.village.org> To: Poul-Henning Kamp Subject: Re: [OT] parallel port for IO? Cc: David Miller , freebsd-hackers@FreeBSD.ORG In-reply-to: Your message of "Thu, 19 Apr 2001 21:41:57 +0200." <60546.987709317@critter> References: <60546.987709317@critter> Date: Thu, 19 Apr 2001 13:52:21 -0600 From: Warner Losh Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG 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