Re: AW: Re[4]: Allowing WAL fsync to be done via O_SYNC

Zeugswetter Andreas SB <ZeugswetterA(at)wien(dot)spardat(dot)at> writes:
>> 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.

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.

regards, tom lane