[Xastir] Findu Trails in 1.4.2

[Curt, WE7U]

On Mon, 14 Feb 2005, Tom Tessier wrote:

> This is on the 1.4.2 with rtree on in Cygwin 1.5.7-1 (version from
> setup.ini) running on a 2.8 GHz Pentium 4 in Windows XP Professional.
>
> After 5-7 requests for Findu trails for stations, Xastir enters some sort of
> state where it uses all of the available CPU, 80-99%. After a number of
> trials, I found that Xastir would do this from as little as 3 requests to as
> many as 15 requests. I let Xastir run for about 20 minutes one time at "full
> CPU" and it did not stop. It was in some sort of loop, evidently. I was
> requesting the "example" trail of K4HG-8, with various start times and
> lengths. This happened most often with long trail lengths, 30+ points, like
> that.
>
> One way I did find to stop this behaviour was to delete .xastir/tmp/map.log
> before each trail download. After I got to about 40, I got tired of
> repeating this...no problems.

Hmmm.  I don't know why deleting that file would have something to
do with it.  Perhaps something errors out if the file it created
suddently disappears, which kiss the process that is causing the
excessive CPU.


> Any ideas?

Always ideas.  It's good ideas that are hard to come by...

What I think is happening:  You're requesting a URL from findu.  For
some reason the wget or libcurl is not timing out, or else you're
able to make a new request before it times out.  As I recall we
spawn this request off to a new process, which waits for the return.
I don't think it was set up to allow multiple requests, so there are
probably global variables that each is waiting on.  The 2nd request
messes up the variables for the first, therefore at least one of the
processes is probably waiting forever for a return.  You might check
to see how many xastir processes show up in "top" or "ps" during
this.  I expect you'll have one extra one compared to before you
started, once you get into this condition.  An extra process during
the request is normal, but it should go away after you get the data.

--
Curt, WE7U.   APRS Client Comparisons: http://www.eskimo.com/~archer
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