Change default VFS timestamp precision?

Poul-Henning Kamp phk at phk.freebsd.dk
Thu Dec 18 20:05:08 UTC 2014


--------
In message <201412181436.31701.jhb at freebsd.org>, John Baldwin writes:

>> >Surely there has to be better ways of doing this stuff. Computers keep
>> >getting faster; it wouldn't be out of the realm of possibility that we
>> >could see a compiler read, compile and spit out a .o inside of a
>> >millisecond. (Obviously not C++, but..)
>> 
>> A millisecond is pushing it, all things considered, it would have to
>> be an utterly trivial source file for a utterly trivial language.

>Eh, the use case I most care about is back-to-back updates to a directory on
>an NFS server.

My comments above was only about compilers in reference to Adrians point.

>I don't understand
>why you think TSP_USEC is slower than TSP_NSEC.  microtime() and nanotime()
>both just call bintime() and then convert the result using similar math.

Because of the pointless nano->micro conversion which makes TSP_USEC
take a division longer to deliver a less precise result than TSP_NSEC.

-- 
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.


More information about the freebsd-arch mailing list