From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gabriel-smtp.zfn.uni-bremen.de (gabriel-smtp.zfn.uni-bremen.de [134.102.50.15]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id EA23F3B29D for ; Tue, 24 Aug 2021 16:38:15 -0400 (EDT) Received: from [192.168.217.118] (p548dc8d5.dip0.t-ipconnect.de [84.141.200.213]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by gabriel-smtp.zfn.uni-bremen.de (Postfix) with ESMTPSA id 4GvLXk3tx8z2xR1; Tue, 24 Aug 2021 22:38:14 +0200 (CEST) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 13.4 \(3608.120.23.2.7\)) From: Carsten Bormann In-Reply-To: Date: Tue, 24 Aug 2021 22:38:14 +0200 Cc: bloat X-Mao-Original-Outgoing-Id: 651530293.979261-c27074950cf96280bebc816e15bec2a8 Content-Transfer-Encoding: quoted-printable Message-Id: <1FFEAE39-AB92-4355-BD4F-7AB334DB4B5E@tzi.org> References: To: Michael Yartys X-Mailer: Apple Mail (2.3608.120.23.2.7) Subject: Re: [Bloat] Possibly interesting video on atomic clocks X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 24 Aug 2021 20:38:16 -0000 On 2021-08-24, at 20:00, Michael Yartys via Bloat = wrote: >=20 > https://www.youtube.com/watch?v=3DJK3eTGkX6qY OMG. Among other things, he says: A cheap Rubidium clock module has a deviation of less than 1 second in = 100 million years (that would be 3e-16!) (1). Because it=E2=80=99s an atomic clock, it sure must be radioactive (2). NTP gives you 400 ms deviations (3). Well, that should be enough to laugh this whole thing off. However: PTP is good (a), and support for it is in many chips (b). It is useful to have a local time reference that is better than a crappy = CPU clock crystal (c) (even if a Rubidium oscillator is overkill, in = particular if you already have PTP to sync with =E2=80=94 go for a cheap = OCXO for a start). Linus=E2=80=99 typical 254,481 views is going to get some attention to = the question of precise clocks on computers =E2=80=94 that is probably = the only good coming from this video, together with complete garbage = such as that your computer must be radioactive to give you a fair gaming = experience. Gr=C3=BC=C3=9Fe, Carsten