Date: Tue, 13 Sep 2011 04:21:39 -0600 From: Brett Glass <brett@lariat.net> To: Adam Vande More <amvandemore@gmail.com> Cc: questions@freebsd.org Subject: Re: Negative ping times with FreeBSD 8.1-RELEASE on older Celeron system Message-ID: <201109131021.EAA26090@lariat.net> In-Reply-To: <CA%2BtpaK2VVdue4MsJpzUxEQABDk1pFVWy_0=CqSEaRifM8CKX5Q@mail.g mail.com> References: <201109122350.RAA21916@lariat.net> <F06D137D-F364-46B2-9458-6882B543B3A6@mac.com> <201109130443.WAA23650@lariat.net> <CA%2BtpaK2VVdue4MsJpzUxEQABDk1pFVWy_0=CqSEaRifM8CKX5Q@mail.gmail.com>
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Thank you! Since it's tunable at runtime I just tested it, and -- sure enough -- no negative ping times. Ironically, it was the kernel that selected the ACPI timer, scoring it higher than the timestamp counter as a clock source. Perhaps code should be added to ensure that the timer is not chosen if it rolls over in less than a second, since this clearly leads to imprecision and missed rollovers. --Brett Glass At 11:04 PM 9/12/2011, Adam Vande More wrote: >it's a runtime tunable so /etc/sysctl.conf
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