From owner-freebsd-arch Wed Apr 17 3:47:51 2002 Delivered-To: freebsd-arch@freebsd.org Received: from zibbi.icomtek.csir.co.za (zibbi.icomtek.csir.co.za [146.64.24.58]) by hub.freebsd.org (Postfix) with ESMTP id 6BEDB37B404 for ; Wed, 17 Apr 2002 03:47:40 -0700 (PDT) Received: (from jhay@localhost) by zibbi.icomtek.csir.co.za (8.11.6/8.11.6) id g3HAkZZ32677; Wed, 17 Apr 2002 12:46:35 +0200 (SAT) (envelope-from jhay) From: John Hay Message-Id: <200204171046.g3HAkZZ32677@zibbi.icomtek.csir.co.za> Subject: Re: get{bin,micro,nano}[up]time() - what precision ? In-Reply-To: <3CBD21B1.2767EE59@mindspring.com> from Terry Lambert at "Apr 17, 2002 00:18:09 am" To: tlambert2@mindspring.com (Terry Lambert) Date: Wed, 17 Apr 2002 12:46:35 +0200 (SAT) Cc: phk@critter.freebsd.dk (Poul-Henning Kamp), arch@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL54 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG > Poul-Henning Kamp wrote: > > In message <3CBB6252.6BAA4E90@mindspring.com>, Terry Lambert writes: > > >SPARC had a 4uS resolution in ~1990; it did this by having a > > >hardware clock of very high resolution, and a low update > > >frequency, from which a delta was maintained in software, > > >rather than by having an update requirement for a full > > >timecounter like structure. > > > > As usual: Please don't pay attention to Terry, he is talking > > without checking his facts and appearantly doesn't even know > > that FreeBSD is way ahead of the pack when it comes to time > > keeping code. > > > I dislike increased imprecision. ... Uhm Terry, aren't you mixing up get{bin,micro,nano}[up]time() with {micro,nano}[up]time()? The last set gives you up to the machine's capability precision. That can be 1ns or better depending on the machine. Both sets are available for use in the kernel John -- John Hay -- John.Hay@icomtek.csir.co.za / jhay@FreeBSD.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message