Date: Mon, 30 Mar 2009 07:32:42 +0000 From: "Poul-Henning Kamp" <phk@phk.freebsd.dk> To: Peter Jeremy <peterjeremy@optushome.com.au> Cc: Alexander Sack <pisymbol@gmail.com>, FreeBSD Hackers <freebsd-hackers@freebsd.org>, freebsd-current@freebsd.org, prashant.vaibhav@gmail.com Subject: Re: Improving the kernel/i386 timecounter performance (GSoC proposal) Message-ID: <9969.1238398362@critter.freebsd.dk> In-Reply-To: Your message of "Mon, 30 Mar 2009 05:07:45 %2B1100." <20090329180745.GB38985@server.vk2pj.dyndns.org>
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In message <20090329180745.GB38985@server.vk2pj.dyndns.org>, Peter Jeremy write s: >>I'm assuming folks are still in love with the TSC because it still the >>cheapest as oppose ACPI-fast or HPET to even contemplate this? > >That is its major advantage. It might be feasible to export all the >data necessary to implement the complete CLOCK_*_FAST family. The general attraction is that it can be read from userland by unpriviledged programs. On systems where the ACPI or HPET hardware can be memory-mapped, I should be equally possible to map those read-only into userland processes. Now _THAT_ would be interesting. -- 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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