Date: Mon, 01 Apr 1996 15:09:22 -0800 From: David Greenman <davidg@Root.COM> To: Bruce Evans <bde@zeta.org.au> Cc: freebsd-current@freefall.freebsd.org, kuku@gilberto.physik.rwth-aachen.de Subject: Re: calcru: negative time: Message-ID: <199604012309.PAA10081@Root.COM>
next in thread | raw e-mail | index | archive | help
>>>[deleted] >>>calcru: negative time: -11929 usec >>>calcru: negative time: -3909 usec >>>calcru: negative time: -3842 usec >>>calcru: negative time: -17709 usec >>>calcru: negative time: -3480 usec >> >>This is caused by hardclock() interrupt latency. The problem is >>especially noticable on i586's and i686's because any latency causes the >>clock to go backwards; on i386's and i486's, the latency must be > 1 >>clock tick (10000 usec) to cause problems. Normally the latency on >>i586's is > 0 but < 10 usec and isn't detectable. There must be bugs >>elsewhere to cause latencies of more than a few tens of usecs. > > I'm not convinced that this is a latency problem. The problem has suddenly >gotten about 1000 times worse earlier today on both -current and -stable >simultaneously...and it's not due to any code changes or load changes. I saw >the problem on machines ranging from wcarchive to my X terminal (which is I'd like to also add that regardless of latency, there's only one word that can describe a clock going backwards: broken. This simply shouldn't happen, ever, and should be fixed. -DG David Greenman Core-team/Principal Architect, The FreeBSD Project
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199604012309.PAA10081>