From owner-freebsd-current@FreeBSD.ORG Sat Jan 24 10:55:00 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id E771616A4CE for ; Sat, 24 Jan 2004 10:55:00 -0800 (PST) Received: from mail.sandvine.com (sandvine.com [199.243.201.138]) by mx1.FreeBSD.org (Postfix) with ESMTP id A2B9043D62 for ; Sat, 24 Jan 2004 10:54:13 -0800 (PST) (envelope-from don@sandvine.com) Received: by mail.sandvine.com with Internet Mail Service (5.5.2657.72) id ; Sat, 24 Jan 2004 13:53:03 -0500 Message-ID: From: Don Bowman To: 'Bill Moran' , current@freebsd.org Date: Sat, 24 Jan 2004 13:52:58 -0500 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2657.72) Content-Type: text/plain; charset="iso-8859-1" Subject: RE: DragonflyBSD kernel clock improvements X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 24 Jan 2004 18:55:01 -0000 > From: Bill Moran [mailto:wmoran@potentialtech.com] > > Hello all, > > I saw this recently: > http://www.dragonflybsd.org/Docs/nanosleep/ > > I was wondering if anyone on the FreeBSD team has looked at > this. It doesn't > appear as if any recent change have been made in the FreeBSD > tree regarding > this. > > It's probably not a big deal, but I just thought I'd point it out. I think its important, we do have some persistent time problems (http://lists.freebsd.org/pipermail/freebsd-stable/2003-November/005194.html ) which seem to require kern.timecounter.method=1 to work around. I think an increased focus on clock accuracy and jitter can't be a bad thing, even if FreeBSD is not a real time system. increasing the repeatability is good for DEVICE_POLLING, for tcp timers, etc. As more and more things move out from under the giant lock, events can become increasingly deterministic. Glad to see someone is putting a scientific method to the problem, it provides a good baseline for increasing the accuracy of measurements. --don