From owner-freebsd-current Mon Sep 22 00:21:02 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id AAA21673 for current-outgoing; Mon, 22 Sep 1997 00:21:02 -0700 (PDT) Received: from schizo.dk.tfs.com (mail.trw.dk [195.8.133.123]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id AAA21659 for ; Mon, 22 Sep 1997 00:20:58 -0700 (PDT) Received: from critter.freebsd.dk (critter.dk.tfs.com [140.145.230.252]) by schizo.dk.tfs.com (8.8.7/8.7.3) with ESMTP id JAA07509; Mon, 22 Sep 1997 09:20:26 +0200 (MET DST) Received: from critter.freebsd.dk (localhost.dk.tfs.com [127.0.0.1]) by critter.freebsd.dk (8.8.7/8.8.7) with ESMTP id JAA00318; Mon, 22 Sep 1997 09:19:49 +0200 (CEST) To: Nate Williams cc: "Justin T. Gibbs" , current@FreeBSD.ORG Subject: Re: cvs commit: src/sys/conf files src/sys/dev/vx if_vx.c if_vxreg.h src/sys/i386/apm apm.c src/sys/i386/conf GENERIC files.i386 src/sys/i386/eisa 3c5x9.c aha1742.c aic7770.c bt74x.c eisaconf.c eisaconf.h if_fea.c if_vx_eisa.c src/sys/i386/i386 autoconf.c ... In-reply-to: Your message of "Sun, 21 Sep 1997 23:05:20 MDT." <199709220505.XAA29116@rocky.mt.sri.com> Date: Mon, 22 Sep 1997 09:19:48 +0200 Message-ID: <316.874912788@critter.freebsd.dk> From: Poul-Henning Kamp Sender: owner-freebsd-current@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk In message <199709220505.XAA29116@rocky.mt.sri.com>, Nate Williams writes: >> 2) New callout interface. This gives O(1) insertion and removal of >> callouts and an O(hash chain length) amount of work to be performed >> in softclock. >... >> the O(n) hit on insertion and removal was painful. The networking >> code is another area that may want to make heavier use of callouts >> now that it is efficient to do so. If you are maintaining a driver >> outside of the tree, or need to update a driver I missed, see the >> timeout.9 man page for details on how the new interface works. For >> those who want to read more about the new implementation, here's a >> pointer to the original paper: >> >> http://www.cs.berkeley.edu/~amc/research/timer/ > >I just read the paper, and it's interesting, but they never give results >based on what the kernel does now. Basically, it's pretty easy to say >that registering/unregistering timers is now much faster, but given that >things can take longer in softclock(), it's not obvious (at least to me) >that this is a win overall, since we call softlock a *heck* of alot more >than we register/de-register timeout/callouts. According to my measurements on my laptop, it's a wash. That means that it will be a win on any other machine I belive. -- Poul-Henning Kamp FreeBSD coreteam member phk@FreeBSD.ORG "Real hackers run -current on their laptop."