Date: Sat, 18 Nov 2000 09:08:06 +0200 (SAT) From: John Hay <jhay@icomtek.csir.co.za> To: mark@grondar.za (Mark Murray) Cc: jhay@icomtek.csir.co.za (John Hay), jhb@FreeBSD.ORG (John Baldwin), arch@FreeBSD.ORG Subject: Re: new monotime() call for all architectures. Message-ID: <200011180708.eAI786418833@zibbi.icomtek.csir.co.za> In-Reply-To: <200011172240.eAHMdtJ07828@gratis.grondar.za> from Mark Murray at "Nov 18, 2000 00:39:57 am"
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> > > It doesn't matter. He just needs a psuedo-timestamp for entropy gathering > > > purposes. It dosen't need to be entirely precise, so if different CPU's > > > counters are not 100% in sync it won't hurt anything. > > > > Ok, I just thought the "mono" in his function name is for monotonic. If > > you are staying on one processor it will work, but if the timestamps > > have scheduling inbetween the timestamps and you land on a different > > processor it won't be monotonic anymore. > > Actually, it does mean "monotonic", but I don't need strictly > monotonic. The "time" info is used to improve the quality of the > harvested entropy, but it is not specifically counted, so the > errors introduced by different CPU's counters are "free" ontropy. Maybe the interface should be private to the random code then. Otherwise a poor unsuspecting soul might assume he can use it in a driver or something and depend on it to be monotonic. John -- John Hay -- John.Hay@icomtek.csir.co.za To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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