Re: very slow drawing

Rene Brun (Rene.Brun@cern.ch)
Fri, 05 Feb 1999 17:40:11 +0000

Thomas Walter wrote:
>
> Rene,
>
> > >
> > > my root-macro executes very fast until it reaches the part,
> > > where the postscript file is generated. The cpu-usage drops
> > > from about 99% to less then 3%.
> > >
> >
> > Thomas,
> > In this part of the macro, you draw 400 histograms. This may take a long
> > time
> > depending how many channels you have per histogram and your options.
>
> 50*( 3 * 128 channels + 2 * 100 channels + 10 ch + 25 ch + 50 ch)
>
> > Is your Postcript file generated on an AFS disk?
>
> No it is generated on the local scratch disk.
>
> > What is the size of the generated ps file?
>
> 2973 KB
>
> But all this doesn't explain the very low cpu-usage. One further thing we
> have to consider the display. I'm computing in Zuerich and displaying
> in Hamburg over a ssh-connection.
>
> Is it possible, that root is waiting for some X11-messages? If this is the
> case, is it possible to generate the ps-file without display the
> histograms on X11?
>

Thomas,
It is clear that you have a problem with the line. The time is not taken
by Postscript but by X.
You can generate the Postscript file by running Root with the batch
option
root -b
Root > .x macro.C

Let me know the result.

Rene Brun