bug#12430: Glitches caused by addition of psec to timers

[Eli Zaretskii]

> Date: Thu, 13 Sep 2012 12:37:23 -0700
> From: Paul Eggert <eggert@cs.ucla.edu>
> CC: monnier@iro.umontreal.ca, 12430@debbugs.gnu.org
> 
> On 09/13/2012 12:19 PM, Eli Zaretskii wrote:
> 
> > Not with correct programs that _want_ the sub-microsecond resolution.
> 
> I don't see how rounding errors could be avoided.  As a trivial example, if I
> write '0.001' in Emacs Lisp, I get a number slightly bigger than 0.001
> due to rounding error, so the underlying OS primitives (which always
> get the ceiling of the delay request) would see two nanoseconds rather
> than the one that I wanted.  OK, so it's only a nanosecond off, but
> the point is that Emacs shouldn't be munging the low-order
> bits of users' requests.

I will remember that when I write a hard-realtime application in Emacs
Lisp.