sub threadwork(){
    lock(MUTEX);
    do{ 
         the work;
    }
}

$t = new threadpool(42 threads);
$t->do( &threadwork() );

lock(MUTEX);
loop{
    ct = timestamp();
    sleep(0.9 seconds); # do a blocking select with timeout in perl for microsecond timings
    loop {nop;} while (ct==timestamp()); # the spinloop 
         #or, for a interval of 5 seconds: while ( ct+5>timestamp() );
    unlock(MUTEX);
}