Date: Fri, 21 Oct 2005 19:19:54 +0200 From: "Poul-Henning Kamp" <phk@phk.freebsd.dk> To: Andre Oppermann <oppermann@networx.ch> Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, Andre Oppermann <andre@freebsd.org>, cvs-all@FreeBSD.org, Bruce Evans <bde@zeta.org.au> Subject: Re: Timekeeping [Was: Re: cvs commit: src/usr.bin/vmstat vmstat.c src/usr.bin/w w.c] Message-ID: <31104.1129915194@critter.freebsd.dk> In-Reply-To: Your message of "Fri, 21 Oct 2005 19:14:25 %2B0200." <435921F1.5E9050AD@networx.ch>
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In message <435921F1.5E9050AD@networx.ch>, Andre Oppermann writes: >> >IMO it's this: >> > >> > Uptime is the time the operating was available to present it's common >> > services to userland. That excludes any suspend and ddb times. Single >> > user mode however counts because the OS was servicing userland even if >> > there was only one user. Uptime is represented in SI seconds. >> >> I can live with this definition. >> >> So now we just need to be able to reliably measure the "not-uptime". > >Umm... Whenever the onesec tick is not incrementing the uptime (and >monotonic) counter. Which conviniently already is the case when OS is >suspended or in DDB. Uhm, yes. Only... How do we measure the time our clock does _not_ tick ? We need to use another clock for that. The RTC comes to mind, but it's precision leaves a lot to be desired. -- 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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