From owner-freebsd-hackers Tue Feb 5 9: 6:56 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from wall.polstra.com (wall-gw.polstra.com [206.213.73.130]) by hub.freebsd.org (Postfix) with ESMTP id D61EA37B422; Tue, 5 Feb 2002 09:06:52 -0800 (PST) Received: from vashon.polstra.com (vashon.polstra.com [206.213.73.13]) by wall.polstra.com (8.11.3/8.11.3) with ESMTP id g15H6qo53253; Tue, 5 Feb 2002 09:06:52 -0800 (PST) (envelope-from jdp@wall.polstra.com) Received: (from jdp@localhost) by vashon.polstra.com (8.11.6/8.11.0) id g15H6pp03714; Tue, 5 Feb 2002 09:06:51 -0800 (PST) (envelope-from jdp) Date: Tue, 5 Feb 2002 09:06:51 -0800 (PST) Message-Id: <200202051706.g15H6pp03714@vashon.polstra.com> To: hackers@freebsd.org From: John Polstra Cc: jhb@freebsd.org Subject: Re: A question about timecounters In-Reply-To: References: Organization: Polstra & Co., Seattle, WA Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG In article , John Baldwin wrote: > > > like, "If X is never locked out for longer than Y, this problem > > cannot happen." I'm looking for definitions of X and Y. X might be > > hardclock() or softclock() or non-interrupt kernel processing. Y > > would be some measure of time, probably a function of HZ and/or the > > timecounter frequency. > > X is hardclock I think, since hardclock() calls tc_windup(). That makes sense, but on the other hand hardclock seems unlikely to be delayed by much. The only thing that can block hardclock is another hardclock, an splclock, or an splhigh. And, maybe, splstatclock. I'm talking about -stable here, which is where I'm doing my experiments. John -- John Polstra John D. Polstra & Co., Inc. Seattle, Washington USA "Disappointment is a good sign of basic intelligence." -- Chögyam Trungpa To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message