Date: Sat, 28 Feb 1998 11:26:35 +0100 (CET) From: Mikael Karpberg <karpen@ocean.campus.luth.se> To: phk@critter.freebsd.dk (Poul-Henning Kamp) Cc: current@FreeBSD.ORG Subject: Re: Curious: "Timecounter"? Message-ID: <199802281026.LAA04326@ocean.campus.luth.se> In-Reply-To: <3448.888596014@critter.freebsd.dk> from Poul-Henning Kamp at "Feb 27, 98 05:13:34 pm"
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According to Poul-Henning Kamp: > In message <19980227095115.05314@urh.uiuc.edu>, dannyman writes: > >arh0300 kernel log messages: > >> Timecounter "i8254" frequency 1193182 Hz cost 2524 ns > >> Timecounter "TSC" frequency 99952423 Hz cost 356 ns [...] > It means that the machine has two pieces of hardware it can use for > the construction of "time-of-day". > > "frequency" should be pretty obvious, "cost" is how long time it takes > to read the counter, and consequently a measure of the overhead by using > that timecounter. Does the system pick the fastest one and use that? Does it use both? (Maybe to see if one of the sources is drifting, etc?) /Mikael To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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