Ralph,
Would this be doable? If we could guarantee that the only output that
went to the file was XML then that would solve the problem.
Greg
On Aug 28, 2009, at 5:39 AM, Ashley Pittman wrote:
On Thu, 2009-08-27 at 23:46 -0400, Greg Watson wrote:
I didn't realize it would be such a problem. Unfortunately there is
simply no way to reliably parse this kind of output, because it is
impossible to know what the error messages are going to be, and
presumably they could include XML-like formatting as well. The whole
point of the XML was to try and simplify the parsing of the mpirun
output, but it now looks like it's actually more difficult.
I thought this might be difficult when I saw you were attempting it.
Let me tell you about what Valgrind does because they have similar
problems. Initially they just had added --xml=yes option which put
most
of the valgrind (as distinct from application) output in xml tags.
This
works for simple cases and if you mix it with --log-file=<filename> it
keeps the valgrind output separate from the application output.
Unfortunately there are lots of places throughout the code where
developers have inserted print statements (in the valgrind case these
all go to the logfile) which means the xml is interspersed with non-
xml
output and hence impossibly to parse reliably.
What they have now done in the current release is to add a extra
--xml-file=<file> option as well as the --log-file=<file> option. Now
in the simple case all output from a normal run goes well formatted to
the xml file and the log file remains empty, any tool that wraps
around
valgrind can parse the xml which is guaranteed to be well formatted
and
it can detect the presence of other messages by looking for output in
the standard log file. The onus is then on tool writers to look at
the
remaining cases and decide if they are common or important enough to
wrap in xml and propose a patch or removal of the non-formatted
message
entirely.
The above seems to work well, having a separate log file for xml is a
huge step forward as it means whilst the xml isn't necessarily
complete
you can both parse it and are able to tell when it's missing
something.
Of course when looking at this level of tool integration it's better
to
use sockets that files (e.g. --xml-socket=localhost:1234 rather than
--xml-file=/tmp/app_XXXX.xml) but I'll leave that up to you.
I hope this gives you something to think over.
Ashley,
--
Ashley Pittman, Bath, UK.
Padb - A parallel job inspection tool for cluster computing
http://padb.pittman.org.uk
_______________________________________________
devel mailing list
de...@open-mpi.org
http://www.open-mpi.org/mailman/listinfo.cgi/devel
