Beefy Boxes and Bandwidth Generously Provided by pair Networks
go ahead... be a heretic

Comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
I see that my approach has been totally bum-over-tits so I consider this case closed :)

Hm. Just because the initial approach is bad, it doesn't mean that the over all goal is unobtainable.

Eg. This almost does what you asked for (note the Inline::C bit is only to get accurate timings; it doesn't affect what the code does):

#! perl -slw use strict; use Inline C => Config => BUILD_NOISY => 1; use Inline C => <<'END_C', NAME => 'rdtsc', CLEAN_AFTER_BUILD => 0; SV *rdtsc() { return newSVuv( (UV)__rdtsc() ); } END_C use threads; use threads::shared; my $sig:shared; my $l0 :shared; my $l1 :shared; my $ts :shared = 0; async( sub { my $lockRef = shift; my $tid = threads ->tid; while( 1 ) { printf "[%5d] Waiting at: %10u ms\n", $tid, ( rdtsc() - $ts + ) / 2400; { lock $$lockRef; cond_wait( $sig, $$lockRef ); } printf "[%5d] Got signal at: %10u ms\n", $tid, ( rdtsc() - $ts + ) / 2400; } }, $_ )->detach for \$l0, \$l1; sleep 1; ## Give threads a chance to start. while( 1 ) { { lock $ts; $ts = rdtsc() }; printf "[main] signalling at: %10u\n", 0; { lock $sig; cond_broadcast( $sig ) }; sleep 3; } __END__ C:\test> [ 1] Waiting at: 7250756853 ms [ 2] Waiting at: 7250765890 ms [main] signalling at: 0 [ 2] Got signal at: 1422 ms [ 1] Got signal at: 1426 ms [ 2] Waiting at: 3361 ms [ 1] Waiting at: 6105 ms [main] signalling at: 0 [ 2] Got signal at: 1384 ms [ 1] Got signal at: 1398 ms [ 2] Waiting at: 3695 ms [ 1] Waiting at: 7011 ms [main] signalling at: 0 [ 2] Got signal at: 1362 ms [ 1] Got signal at: 1361 ms [ 2] Waiting at: 3672 ms [ 1] Waiting at: 7077 ms Terminating on signal SIGINT(2)

NB: ms above is microseconds!

But note that even on my 4 core system, the 2 threads do not see the signal at exactly the same time. (also, if you leave it running, you'll see one of the limitations (a.k.a total idiocies) of the cond_var mechanism.

But that brings me back to the questions I alluded to earlier. Why have your main thread attempt to coordinate starting two other threads; and then just sit there doing nothing? Ie, why use 3 threads?

I can see that you might need to run the recorder and player from different threads, but why not:

main: start recorder thread; main: start player (in main); main: wait for player to finish; main: signal recorder thread to stop.

This mirrors what you'd do manually. Switch the recorder on; switch the player on; when the player finishes; switch the recorder off.

There is plenty of scope for solving the problem; you just need to tackle it the right way.

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

In reply to Re^2: Synchronising threads with signals (or not) by BrowserUk
in thread Synchronising threads with signals (or not) by forestcreature

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, 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, 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.
  • Log In?

    What's my password?
    Create A New User
    [marto]: Corion if your device has an official Oreo ROM I'd do a nandroid backup and give it a shot
    [marto]: I've been impressed with the Star Citizen thing, I'll likely never play it, but they've achieved something really special I think, in terms of what has been shown so far.

    How do I use this? | Other CB clients
    Other Users?
    Others romping around the Monastery: (4)
    As of 2017-12-14 10:47 GMT
    Find Nodes?
      Voting Booth?
      What programming language do you hate the most?

      Results (389 votes). Check out past polls.