Re: st: Sloooow Graphics

[David Kantor <dkantor@jhu.edu>]

At 10:18 AM 6/29/2004 -0400, Jean-Philippe C. Stijns wrote:

> Hi All, Does anyone know why Stata is so slow to produce graphs. I have
> already set my mem to 200m. Is there any other potential issue? Thank you.
First, Graphics were completely rewritten as of Stata 8, and they are 
slower than before.  But you get much more capability and customizability.

For my own use, I do not use graphics often, and I have not learned much 
about the new graphics. So, for the rare times I need graphics, I will 
often use the old version -graph7- or -gr7-.  While this is retro 
technology, and you could criticize me for not keeping up-to-date, it has 
two advantages: I already know how to use it (as far as I need it), and it 
is faster.  Often, the speed advantage alone is compelling enough to make 
me prefer it.

See -help graph7- or -help gr7- for more details, including links to other 
version 7 graphing programs.

The other matter is that you set mem to 200m. You should be aware that at a 
certain point, setting mem to a high value will cause major slowdown -- a 
quantum leap downward in speed.  This is when you run out of actual memory 
and you start to use virtual memory. When this happens depends on several 
factors, some of which are a bit unpredictable.  These are: amount of 
physical memory on the machine, how much memory is allocated to other 
processes, and what operating system you use. (My experience with Windows 
is that, with no other user processes running, I can take about 85% of the 
machine's physical memory before virtual memory kicks in.  This is my 
experience, whereas some system experts have told me to expect this to be 
more like 50%.  It may be that the portion needed by the system is 
relatively constant -- rather than proportional.)  It's actually more 
complicated, as what you really need is contiguous memory, if I understand 
it correctly. There may be some FAQs or archived Statalist messages on this 
matter.

And I should add that, as I understand it, prior to the point of invoking 
virtual memory, taking more memory will not speed up your processing; but 
it will make the difference in whether your processing can run at all.

I hope this helps.
-- David

David Kantor
Institute for Policy Studies
Johns Hopkins University
dkantor@jhu.edu
410-516-5404

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