[plt-scheme] High precision timing and MrEd/OSX

From: Rohan Drape (rd at alphalink.com.au)
Date: Tue Dec 21 00:00:46 EST 2004

On Mon, 20 Dec 2004 20:28:14 -0700, Matthew Flatt wrote
> MrEd does start a helper Posix thread under OS X, and maybe the problem
> is that the helper thread can't deal with the signal?

That sounds quite possible, I will look into it when I am on a 
machine with PLT sources.  Many thanks.  (I had only examined the wx
directory for issues, sleep/usleep/alarm/sigmask etc. could all cause

> But your earlier message didn't say exactly what goes wrong under OS 
> X. Does the extension simply fail to report the correct time, or 
> does MrEd itself break?

Under MrEd/OSX the timer has a resolution of about one second, under 
mzscheme/OSX the resolution is actually very good (excepting GC jitter).

The relatively consistent delay seems to indicate that it is a
signalling issue.  I did not know of the helper thread, possibly 
that can be finetuned.

Thanks again,

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