From: | Zeugswetter Andreas SB <ZeugswetterA(at)wien(dot)spardat(dot)at> |
---|---|
To: | "'Tom Lane'" <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | Alfred Perlstein <bright(at)wintelcom(dot)net>, pgsql-hackers(at)postgresql(dot)org |
Subject: | AW: AW: Re[4]: Allowing WAL fsync to be done via O_SYNC |
Date: | 2001-03-19 12:15:52 |
Message-ID: | 11C1E6749A55D411A9670001FA687963368253@sdexcsrv1.f000.d0188.sd.spardat.at |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
> >> It's great as long as you never block, but it sucks for making things
> >> wait, because the wait interval will be some multiple of 10 msec rather
> >> than just the time till the lock comes free.
>
> > On the AIX platform usleep (3) is able to really sleep microseconds without
> > busying the cpu when called for more than approx. 100 us (the longer the interval,
> > the less busy the cpu gets) .
> > Would this not be ideal for spin_lock, or is usleep not very common ?
> > Linux sais it is in the BSD 4.3 standard.
>
> HPUX has usleep, but the man page says
>
> The usleep() function is included for its historical usage. The
> setitimer() function is preferred over this function.
I doubt that setitimer has microsecond precision on HPUX.
> In any case, I would expect that all these functions offer accuracy
> no better than the scheduler's regular clock cycle (~ 100Hz) on most
> kernels.
Not on AIX, and I don't beleive that for the majority of other UNIX platforms eighter.
I do however suspect, that some implementations need a busy loop, which would,
if at all, only be acceptable on an SMP system.
Andreas
From | Date | Subject | |
---|---|---|---|
Next Message | Rod Taylor | 2001-03-19 12:28:21 | Fw: [vorbis-dev] ogg123: shared memory by mmap() |
Previous Message | Alexander Klimov | 2001-03-19 11:47:37 | Re: Re: problems with startup script on upgrade |