diff options
Diffstat (limited to 'docs/tutorials/017/page06.html')
| -rw-r--r-- | docs/tutorials/017/page06.html | 206 |
1 files changed, 0 insertions, 206 deletions
diff --git a/docs/tutorials/017/page06.html b/docs/tutorials/017/page06.html deleted file mode 100644 index 8e3704b1b32..00000000000 --- a/docs/tutorials/017/page06.html +++ /dev/null @@ -1,206 +0,0 @@ -<!-- $Id$ --> -<HTML> -<HEAD> - <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> - <META NAME="Author" CONTENT="James CE Johnson"> - <TITLE>ACE Tutorial 017</TITLE> -</HEAD> -<BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#000FFF" VLINK="#FF0F0F"> - -<CENTER><B><FONT SIZE=+2>ACE Tutorial 017</FONT></B></CENTER> - -<CENTER><B><FONT SIZE=+2>Using the ACE_Barrier synch object</FONT></B></CENTER> - -<P> -<HR WIDTH="100%"> -I could have included this in the first Test object of the tutorial -but that may have complicated things a bit. What we're doing here is -recognizing when the "owner" thread adds more threads to the pool. -When we notice that, we use the barrier to wait until everything -stabilizes and then we recalibrate and move on. -<P> -The source is <A HREF="barrier2.cpp">here</A>. -<HR> -<PRE> - -<font color=red>// $Id$</font> - -<font color=blue>#include</font> "<font color=green>Barrier_i.h</font>" -<font color=blue>#include</font> "<A HREF="../../../ace/Task.h">ace/Task.h</A>" - -<font color=red>/* We'll use a simple Task<> derivative to test our new Barrier - object. -*/</font> -class Test : public ACE_Task<ACE_NULL_SYNCH> -{ -public: - - <font color=red>// Construct the object with a desired thread count</font> - Test(int _threads); - - <font color=red>// Open/begin the test. As usual, we have to match the</font> - <font color=red>// ACE_Task signature.</font> - int open(void * _unused = 0); - - <font color=red>// Change the threads_ value for the next invocation of open()</font> - void threads(int _threads); - - <font color=red>// Get the current threads_ value.</font> - int threads(void); - - <font color=red>// Perform the test</font> - int svc(void); - -protected: - <font color=red>// How many threads the barrier will test.</font> - u_int threads_; - - <font color=red>// The Barrier object we'll use in our tests below</font> - Barrier barrier_; - - <font color=red>// This lets us pick one (eg -- the first) thread as the</font> - <font color=red>// "<font color=green>controller</font>" for our little test...</font> - ACE_Atomic_Op<ACE_Mutex,u_int> tcount_; -}; - -<font color=red>/* Construct the object & initialize the threads value for open() to - use. -*/</font> -<font color=#008888>Test::Test</font>(int _threads) - : threads_(_threads), tcount_(0) -{ -} - -<font color=red>/* As usual, our open() will create one or more threads where we'll do - the interesting work. -*/</font> -int <font color=#008888>Test::open</font>(void * _unused) -{ - ACE_UNUSED_ARG(_unused); - - <font color=red>// One thing about the barrier: You have to tell it how many</font> - <font color=red>// threads it will be synching. The threads() mutator on my</font> - <font color=red>// Barrier class lets you do that and hides the implementation</font> - <font color=red>// details at the same time.</font> - barrier_.threads(threads_); - - <font color=red>// Activate the tasks as usual...</font> - return this->activate(THR_NEW_LWP, threads_, 1); -} - -void <font color=#008888>Test::threads</font>(int _threads) -{ - threads_ = _threads; -} - -int <font color=#008888>Test::threads</font>(void) -{ - return threads_; -} - -<font color=red>/* svc() will execute in each thread & do a few things with the - Barrier we have. - */</font> -int <font color=#008888>Test::svc</font>(void) -{ - <font color=red>// Say hello to everyone first.</font> - ACE_DEBUG(( LM_INFO, "<font color=green>(%P|%t|%T) Created\n</font>" )); - - <font color=red>// Increment and save the "<font color=green>tcount</font>" value. We'll use it in</font> - <font color=red>// just a moment...</font> - int me = ++tcount_; - - <font color=red>// Wait for all initial threads to get to this point before we</font> - <font color=red>// go any further. This is standard barrier usage...</font> - barrier_.wait(); - - <font color=red>// Setup our random number generator.</font> - ACE_Time_Value now(<font color=#008888>ACE_OS::gettimeofday</font>()); - ACE_RANDR_TYPE seed = now.usec(); - <font color=#008888>ACE_OS::srand</font>(seed); - int delay; - - <font color=red>// We'll arbitrarily choose the first activated thread to be</font> - <font color=red>// the controller. After it sleeps a few seconds, it will add</font> - <font color=red>// five threads.</font> - if( me == 1 ) - { - <font color=red>// Sleep from 1 to 10 seconds so that some of the other</font> - <font color=red>// threads will be into their for() loop.</font> - delay = <font color=#008888>ACE_OS::rand_r</font>(seed)%10; - <font color=#008888>ACE_OS::sleep</font>(abs(delay)+1); - - <font color=red>// Make ourselves the barrier owner so that we can change</font> - <font color=red>// the number of threads. This should be done with care...</font> - barrier_.owner( <font color=#008888>ACE_OS::thr_self</font>() ); - - <font color=red>// Add 5 threads to the barrier and then activate() to</font> - <font color=red>// make them real. Notice the third parameter to</font> - <font color=red>// activate(). Without this parameter, the threads won't</font> - <font color=red>// be created.</font> - if( barrier_.threads(threads_+5) == 0 ) - { - this->activate(THR_NEW_LWP,5,1); - } - } - - <font color=red>// This for() loop represents an "<font color=green>infinite</font>" work loop in an</font> - <font color=red>// application. The theory is that the threads are dividing up</font> - <font color=red>// some work but need to "<font color=green>recalibrate</font>" if more threads are</font> - <font color=red>// added. I'll just do five iterations so that the test</font> - <font color=red>// doesn't run forever.</font> - int i; - for( i = 0 ; i < 5 ; ++i ) - { - <font color=red>// The sleep() represents time doing work.</font> - delay = <font color=#008888>ACE_OS::rand_r</font>(seed)%7; - <font color=#008888>ACE_OS::sleep</font>(abs(delay)+1); - - ACE_DEBUG(( LM_INFO, "<font color=green>(%P|%t|%T)\tThread %.2d of %.2d iteration %.2d\n</font>", me, threads_, i )); - - <font color=red>// If the local threads_ variable doesn't match the number</font> - <font color=red>// in the barrier, then the controller must have changed</font> - <font color=red>// the thread count. We'll wait() for everyone and then</font> - <font color=red>// recalibrate ourselves before continuing.</font> - if( this->threads_ != barrier_.threads() ) - { - ACE_DEBUG(( LM_INFO, "<font color=green>(%P|%t|%T) Waiting for thread count to increase to %d from %d\n</font>", - barrier_.threads(), this->threads_ )); - - <font color=red>// Wait for all our sibling threads...</font> - barrier_.wait(); - - <font color=red>// Set our local variable so that we don't come here again.</font> - this->threads_ = barrier_.threads(); - - <font color=red>// Recalibration can be anything you want. At this</font> - <font color=red>// point, we know that all of the threads are synch'd</font> - <font color=red>// and ready to go.</font> - } - } - - <font color=red>// Re-synch all of the threads before they exit. This isn't</font> - <font color=red>// really necessary but I like to do it.</font> - barrier_.done(); - - return(0); -} - -<font color=red>/* Our test application... - */</font> -int main(int, char**) -{ - <font color=red>// Create the test object with 5 threads</font> - Test test(5); - - <font color=red>// and open it to test the barrier.</font> - test.open(); - <font color=red>// Now wait for them all to exit.</font> - test.wait(); - - return(0); -} -</PRE> -<P><HR WIDTH="100%"> -<CENTER>[<A HREF="../online-tutorials.html">Tutorial Index</A>] </CENTER> - |