Comment 4 for bug 171252

there is another bug report requesting more progress
information in general (which I intend to leave open
seperate to this request) and in it the reporter mentions
the specific task of unlinking a large group of clones.

it may be helpful to go to that report (just search for
"progress") and mention other operations which are very
slow. this may also provide useful suggestion to any
developers interested in improving performance problems
irrespective of any efforts to provide more progress feedback.

on closer inspection i noticed potrace is also available in
the form of a library
http://potrace.sourceforge.net/potracelib.pdf

If the potrace functionality in inkscape was rewritten to
use the library rather than wrapping the command line
utilities as then perhaps it would then be possible to
provide reasonable progress information
such a rewrite might also help integrate potrace in other
wasy and maybe make it easier to have potrace on other
platforms but it does seem like a whole lot of work for very
little visible gain.