Date: Thu, 22 Mar 2007 09:06:52 -0400 From: "Olson, Arthur David \(NIH/NCI\) [E]" <olsona@dc37a.nci.nih.gov> To: "Andriy Gapon" <avg@icyb.net.ua>, <freebsd-amd64@freebsd.org>, <freebsd-stable@freebsd.org> Cc: wollman@freebsd.org Subject: RE: zdump on amd64 Message-ID: <B410D30A78C6404C9DABEA31B54A2813016CE3E6@nihcesmlbx10.nih.gov> In-Reply-To: <46013D6F.4020704@icyb.net.ua> References: <45FE9B11.5030909@icyb.net.ua> <46013D6F.4020704@icyb.net.ua>
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Check the version of zdump in use with a... zdump --version ...command; starting with the February 2006 (8.1) version, output has been limited to run from the year -500 to the year 2500 by default. The range can be changed using the... -c [loyear],hiyear ...option. --ado -----Original Message----- From: Andriy Gapon [mailto:avg@icyb.net.ua] Sent: Wednesday, March 21, 2007 10:13 AM To: freebsd-amd64@freebsd.org; freebsd-stable@freebsd.org Cc: wollman@freebsd.org; tz@lecserver.nci.nih.gov Subject: Re: zdump on amd64 on 19/03/2007 16:15 Andriy Gapon said the following: > Strange problem: > $ uname -srm > FreeBSD 6.2-RELEASE-p2 amd64 > > $ zdump -v EST > EST Sun Jan 26 08:29:52 -219 UTC = Sun Jan 26 03:29:52 -219 EST isdst=0 > gmtoff=-18000 > EST Mon Jan 27 08:29:52 -219 UTC = Mon Jan 27 03:29:52 -219 EST isdst=0 > gmtoff=-18000 > EST Fri Jan 1 04:59:59 -219 UTC = Thu Dec 30 23:59:59 -219 EST isdst=0 > gmtoff=-18000 > EST Fri Jan 1 05:00:00 -219 UTC = Fri Jan 1 00:00:00 -219 EST isdst=0 > gmtoff=-18000 > ^C ... > Before each ^C zdump was hanging eating 100% CPU. > Something about 64-bitness ? Hmm. I hurried to assert that it was hanging, it was actually searching. It seems that zdump -v algorithm is to start with minimal time_t possible (large negative number in our case) and to go to maximum time_t using 12 hours increments and doing certain checks for DST jumps. Well, with 64-bit time_t start date is somewhere 200 milliard (10^9) years ago and end date is the same in the future, so iteration over those years takes quite a while. And tz db doesn't contain anything useful for too distant years anyway. I think that zdump should be optimized to limit its search range. At the very least for the start point - what is current estimate of the age of our Universe :-) -- Andriy Gapon
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