Date: Wed, 11 Jul 2012 09:44:44 -0500 From: Paul Albrecht <albrecht@glccom.com> To: Alexander Motin <mav@FreeBSD.org> Cc: "davide@FreeBSD.org" <davide@FreeBSD.org>, "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>, Harti Brandt <hartmut.brandt@dlr.de> Subject: Re: [[SPAM]] Re: kqueue timer timeout period Message-ID: <1342017884.5984.24.camel@albrecht-desktop> In-Reply-To: <4FFD4A7F.9060103@FreeBSD.org> References: <4FFD4A7F.9060103@FreeBSD.org>
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On Wed, 2012-07-11 at 04:42 -0500, Alexander Motin wrote: > Hi. > > Historically FreeBSD used completely different hardware time sources for > time keeping and time events. Not sure about 5%, but the last could be > less precise in some cases. FreeBSD 9.0, depending on hardware, can be > more precise because of using same time source in both cases. Also there > is ongoing GSoC project now by Davide Italiano to handle sub-HZ > resolution for time events. Present tests show reaching 20 microseconds > precision; and I think it can be improved further. > I'm definitely not getting getting 20 millisecond timing with freebsd kqueue which surprised me because I get it with linux linuxfd_create/read using the same hardware. -- Paul Albrecht
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