Re: RE: [COMMITTERS] pgsql/src/backend/access/transam ( xact.c xlog.c)

On Thu, 16 Nov 2000, Alfred Perlstein wrote:

> * Larry Rosenman <ler(at)lerctr(dot)org> [001116 12:09] wrote:
> > * Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> [001116 14:02]:
> > > > > This sounds like an interesting approach, yes.
> > > > Question: Is sleep(0) guaranteed to at least give up control?
> > > >
> > > > The way I read my UnixWare 7's man page, it might not, since alarm(0)
> > > > just cancels the alarm...
> > >
> > > Well, it certainly is a kernel call, and most OS's re-evaluate on kernel
> > > call return.
> > BUT, do we know for sure that sleep(0) is not optimized in the library
> > to just return?
>
> sleep(3) should conform to POSIX specification, if anyone has the
> reference they can check it to see what the effect of sleep(0)
> should be.

Yes, but Posix also specifies sched_yield() which rather explicitly
allows a process to yield its timeslice. No idea how well that is
supported.

> --
> -Alfred Perlstein - [bright(at)wintelcom(dot)net|alfred(at)freebsd(dot)org]
> "I have the heart of a child; I keep it in a jar on my desk."

Tom