From what I can see from the code, you are launching threads from a Tk callback 
 $mw->{'start_b'} = $mw->Button('-relief' => 'raised',
                                   '-text' => 'START',
                                   '-command' => sub
                                   {
                                       evWorkStart(\%thread_data);
                                       
                                   });

[download]

I am surprised that you are not having thread crashes due to Tk's non-threadsafety. The code might work good if converted to Gtk2, which has better thread safety.

Back to your problem, I did something awhile back, that showed how to reuse threads with Tk... see Tk-with-worker-threads. Some of the improvements in perl thread signal handling, have since made my nested loops unnessary, thru thread signal handling. See using the thread->kill() feature on linux

But the main idea to make non-polluting code, is to recycle and reuse of course, so see Tk-with-worker-threads

Just beware, that Tk is NOT threadsafe, and unless you follow the many precautions, listed here, by various monks, you will have problems. See Re: Perl Tk and Threads

I'm not really a human, but I play one on earth.
Old Perl Programmer Haiku ................... flash japh

In reply to Re: Tk and Threads by zentara
in thread Tk and Threads by Dirk80

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.