Date: Mon, 12 Aug 2002 13:10:02 -0700 (PDT) From: Garrett Wollman <wollman@lcs.mit.edu> To: freebsd-bugs@FreeBSD.org Subject: kern/41552: TCP timers' sysctl's overflow Message-ID: <200208122010.g7CKA2MT097912@freefall.freebsd.org>
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The following reply was made to PR kern/41552; it has been noted by GNATS. From: Garrett Wollman <wollman@lcs.mit.edu> To: "G.P. de Boer" <g.p.de.boer@st.hanze.nl> Cc: freebsd-gnats-submit@FreeBSD.ORG Subject: kern/41552: TCP timers' sysctl's overflow Date: Mon, 12 Aug 2002 15:45:22 -0400 (EDT) <<On Mon, 12 Aug 2002 21:21:33 +0200, "G.P. de Boer" <g.p.de.boer@st.hanze.nl> said: > Well.. since LINT says 1000Hz is advisable for dummynet use. For > polling 1000 or even 2000Hz is advised. IF this is a problem with > RFC1323, which strikes me as odd, then there's more to this problem > than meets the eye. A setting in LINT shouldn't break anything so > fundamental as TCP. RFC 1323 specifies that the timestamp clock is to have a period between 1 ms and 1 s. (See page 21, third paragraph from the bottom.) The timestamp clock in FreeBSD is the system variable `ticks', which is incremented once for every clock interrupt, so its period is approximately 1/HZ s. In order to support higher clock frequencies, a scaling factor would need to be introduced. -GAWollman To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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