From owner-freebsd-arch@FreeBSD.ORG Wed Nov 15 08:40:30 2006 Return-Path: X-Original-To: arch@freebsd.org Delivered-To: freebsd-arch@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8F86916A403 for ; Wed, 15 Nov 2006 08:40:30 +0000 (UTC) (envelope-from peterjeremy@optushome.com.au) Received: from mail28.syd.optusnet.com.au (mail28.syd.optusnet.com.au [211.29.133.169]) by mx1.FreeBSD.org (Postfix) with ESMTP id E216943D45 for ; Wed, 15 Nov 2006 08:40:29 +0000 (GMT) (envelope-from peterjeremy@optushome.com.au) Received: from turion.vk2pj.dyndns.org (c58-107-94-118.belrs4.nsw.optusnet.com.au [58.107.94.118]) by mail28.syd.optusnet.com.au (8.13.1/8.13.1) with ESMTP id kAF8eQjW027520 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 15 Nov 2006 19:40:27 +1100 Received: from turion.vk2pj.dyndns.org (localhost.vk2pj.dyndns.org [127.0.0.1]) by turion.vk2pj.dyndns.org (8.13.8/8.13.8) with ESMTP id kAF8eQFM001415; Wed, 15 Nov 2006 19:40:26 +1100 (EST) (envelope-from peter@turion.vk2pj.dyndns.org) Received: (from peter@localhost) by turion.vk2pj.dyndns.org (8.13.8/8.13.8/Submit) id kAF8ePGX001414; Wed, 15 Nov 2006 19:40:25 +1100 (EST) (envelope-from peter) Date: Wed, 15 Nov 2006 19:40:25 +1100 From: Peter Jeremy To: Poul-Henning Kamp Message-ID: <20061115084025.GA914@turion.vk2pj.dyndns.org> References: <20061113234305.A34147@xorpc.icir.org> <9674.1163493637@critter.freebsd.dk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="opJtzjQTFsWo+cga" Content-Disposition: inline In-Reply-To: <9674.1163493637@critter.freebsd.dk> X-PGP-Key: http://members.optusnet.com.au/peterjeremy/pubkey.asc User-Agent: Mutt/1.5.13 (2006-08-11) Cc: arch@freebsd.org Subject: Re: a proposed callout API X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 15 Nov 2006 08:40:30 -0000 --opJtzjQTFsWo+cga Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, 2006-Nov-13 21:38:21 +0000, Poul-Henning Kamp wrote: >The other thing is that covering the entire range from hour long >callouts to nanosecond callouts would require a 64 bit value or >a tricky pseudo-FP encoding. By splitting them in two classes, >I can use two different 31 bit encodings separated by the top bit. This sounds like a pseudo-FP encoding with a very small exponent and a relatively large mantissa :-) On Tue, 2006-Nov-14 08:40:37 +0000, Poul-Henning Kamp wrote: >In message <20061113234305.A34147@xorpc.icir.org>, Luigi Rizzo writes: > >>To make a proper evaluation i would need some idea of the number >>and distribution of scheduled events on a busy box [...] > >So do I. > >What is important right now however, is the API. The implementation >behind it we can change every week if we want, but the API affects >far too many kernel files to get it wrong. I don't see anything obviously wrong with the API as proposed. The use of an opaque tick_t rather than requiring scaling on each call seems an obvious improvement. That said, is it worthwhile to instrument the existing callout code to get some statistics on what actions are frequently used - that might suggest operations that need to be cheap. (Though identifying high-level actions like repeat/arm/disarm might be difficult). --=20 Peter Jeremy --opJtzjQTFsWo+cga Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (FreeBSD) iD8DBQFFWtJ5/opHv/APuIcRAou2AJ45R8IvuFjjGBkwwgnQFoo08Pj7gACfdm8O kbaJkiB5tC1lpJzn15USdkc= =+XtB -----END PGP SIGNATURE----- --opJtzjQTFsWo+cga--