[GRASSLIST:4817] Re: v.digit and other interactive commands

[Dylan Beaudette]

On Friday 12 November 2004 03:46 am, you wrote:
> Hamish wrote:
> > > This is probably not related to the last couple of posts on v.digit
> > > crashing... but it seems like a lot of the interactive programs like
> > > v.digit will send my processor useage up to near 100% when it is
> > > waiting for user input...
> > >
> > > Any ideas?
> >
> > yeah.. the code which waits for you to press a mouse button is a loop.
> > Usually you would have it sleep for a tenth of a second between
> > checking, but the usleep() function in the C library isn't portable
> > across all the computing platforms that GRASS supports.
> >
> > There is one called sleep() which will work on everyones' systems, but
> > it will only let the system go to sleep for 1 second at a time which
> > makes reaction time way too slow. So we just leave it checking as fast
> > as the computer can check, which is why you are pegged at 100%.
> >
> > annoying but harmless for the most part.
> >
> > Note that d.zoom from the command line in 5.3 is fine, in 5.7 it is not.
> > 5.7's d.what.vect is especially bad at this.
> >
> > This is even worse when you are running grass remotely over the network.
> >
> >
> > suggestions for fixing this are welcome..
>
> Use select() on both the X connection and the monitor socket. See
> Get_Xevent() in Serve_Xevent.c.

Would this be all that it would take to fix the 100% CPU load while waiting 
for input? If I had the skills to implement this I would... but alas. It sure 
would be nice to not have GRASS pegging my CPU at 100% for simple 
operations...

--
Dylan Beaudette
Soil Science Graduate Group
University of California at Davis