Re: [LEAPSECS] Introduction of long term scheduling

From: Poul-Henning Kamp <phk_at_PHK.FREEBSD.DK>
Date: Sat, 06 Jan 2007 19:21:25 +0000

In message <>, Tony Fin
ch writes:
>On Sat, 6 Jan 2007, M. Warner Losh wrote:
>> OSes usually deal with timestamps all the time for various things. To
>> find out how much CPU to bill a process, to more mondane things.
>> Having to do all these gymnastics is going to hurt performance.
>That's why leap second handling should be done in userland as part of the
>conversion from clock (scalar) time to civil (broken-down) time.

I would agree with you in theory, but badly designed filesystems
like FAT store timestamps in encoded YMDHMS format, so the kernel
need to know the trick as well. (There are other examples, but not
as well known).

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk_at_FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
Received on Sat Jan 06 2007 - 11:37:47 PST

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