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User space gettimeofday()

Posted Dec 19, 2002 3:54 UTC (Thu) by kbob (guest, #1770)
Parent article: How to speed up system calls

Gettimeofday() may not be practical in user space, but
getpid() certainly is. Other syscalls without side effects
that return infrequently changing information could also be
put into user space.

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User space getpid()

Posted Dec 19, 2002 5:53 UTC (Thu) by ncm (subscriber, #165) [Link]

While getpid() could certainly be put in user space, the
number of programs that it would speed up noticeably
could probably be counted on a pig's hoof. It would be
pretty surprising if any syscall used frequently enough
to make a difference could be handled in user space.

gettimeofday() is called so frequently in real programs
that any speedup matters, at least for some programs.
Few other syscalls have that property.

User space gettimeofday()

Posted Dec 20, 2002 0:19 UTC (Fri) by acristianb (guest, #1702) [Link]

What are the side effects of gettimeofday?

User space gettimeofday()

Posted Dec 20, 2002 20:54 UTC (Fri) by jmshh (guest, #8257) [Link]

None. But there were two conditions, the other being "infrequently
changing information". Updates require cache invalidation, and this is
better done when the data is really needed only.