Date: Sun, 06 Apr 2003 20:54:08 +0200 From: "Poul-Henning Kamp" <phk@phk.freebsd.dk> To: des@ofug.org (Dag-Erling =?iso-8859-1?q?Sm=F8rgrav?=) Cc: current@freebsd.org Subject: Re: weird fxp / timecounter interaction in top-of-tree Message-ID: <28859.1049655248@critter.freebsd.dk> In-Reply-To: Your message of "Sun, 06 Apr 2003 20:40:24 %2B0200." <xzp4r5bmpuv.fsf@flood.ping.uio.no>
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In message <xzp4r5bmpuv.fsf@flood.ping.uio.no>, Dag-Erling =?iso-8859-1?q?Sm=F8 rgrav?= writes: >"Poul-Henning Kamp" <phk@phk.freebsd.dk> writes: >> > and tc_init() to use the *first* timecounter it runs across (on i386, >> > this is generally the i8254), leaving the admin to pick another one if >> > the default does not suit her. See the attached patch. >> This is wrong. Please do not commit it. > >OK. Any suggestion as to how we could rank timecounters so we can >switch to a better one when it becomes available? Is this something >we can determine statically (with a compiled-in preference list), or >do we have to determine it at run time? Defining "best" is at best hard, so I have resorted to the simple technique we use now: Don't call tc_init on a timecounter unless you want to use it. Provided people set it sensibly, we could add a "priority" field to the timecounter structure and have tc_init() respect that. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.
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