mutex3.cxx

eCos1.31版

static void t3( CYG_ADDRWORD data )
{
    Cyg_Thread *self = Cyg_Thread::self();

    CYG_TEST_INFO( "Thread 3 running" );

    mutex.lock();

    self->delay( DELAYFACTOR * 5 );    // let thread 3a run

    thread[2]->resume();                // resume thread 2

    while ( 0 == go_flag )
        self->delay(1);                 // wait until we are told to go

    t3ran ++;                           // record the fact

    CYG_TEST_CHECK( 0 == got_it, "Thread 1 claims to have got my mutex" );
    
    mutex.unlock();
    
    t3ended ++;                         // record that we came back

    CYG_TEST_CHECK( 1 == got_it, "Thread 1 did not get the mutex" );

    CYG_TEST_INFO( "Thread 3 exit" );
}

// ------------------------------------------------------------------------

static void control_thread( CYG_ADDRWORD data )
{
    Cyg_Thread *self = Cyg_Thread::self();
    int i;

    CYG_TEST_INIT();
    CYG_TEST_INFO( "Control Thread running" );

    // Go through the 27 possibilitied of resuming the extra threads
    //     0: not at all
    //     1: early in the process
    //     2: later on
    // which are represented by bits 0-3 and 4-6 resp in the argument to
    // thread 2 (none set means no resume at all).
    for ( i = 0; i < 27; i++ ) {
        static int xx[] = { 0, 1, 16 };
        int j = i % 3;
        int k = (i / 3) % 3;
        int l = (i / 9) % 3;

        int d = xx[j] | (xx[k]<<1) | (xx[l]<<2) ;

        if ( cyg_test_is_simulator && (0 != i && 13 != i && 26 != i) )
            continue;    // 13 is 111 base 3, 26 is 222 base 3

#ifdef CYGSEM_KERNEL_SYNCH_MUTEX_PRIORITY_INHERITANCE
        // If the simple scheme plus relay enhancement, or any other
        // *complete* scheme, we can run all three ancillary threads no
        // problem, so no special action here.

#ifdef CYGSEM_KERNEL_SYNCH_MUTEX_PRIORITY_INHERITANCE_SIMPLE
#ifndef CYGSEM_KERNEL_SYNCH_MUTEX_PRIORITY_INHERITANCE_SIMPLE_RELAY
        // If the simple scheme but no relay enhancement:
        if ( k )                        // Cannot run thread 2a nor 3a
            break;                      //     if no priority relay.
#endif
#endif

#else
        // If no priority inheritance at all, running threads 1a and 2a is
        // OK, but not thread 3a; it blocks the world.
        if ( l )                        // Cannot run thread 3a if no
            break;                      //     priority inheritance at all.
#endif

        mutex = Cyg_Mutex();            // Reinitialize this

        got_it  = 0;
        t3ran   = 0;
        t3ended = 0;
        for ( int z = 0; z < 4; z++ ) extras[z] = 0;
        go_flag = 0;
        
        new_thread( t1, 0,  5, 1 );            // Slot 1
        new_thread( t2, d, 10, 1 );            // Slot 2
        new_thread( t3, 0, 15, 1 );            // Slot 3
        
        new_thread( extra_thread, 1,  8, j );  // Slot 4
        new_thread( extra_thread, 2, 12, k );  // Slot 5
        new_thread( extra_thread, 3, 17, l );  // Slot 6
        
        {
            static char *a[] = { "inactive", "run early", "run late" };
            diag_printf( "\n----- [%2d] New Cycle: 0x%02x, Threads 1a %s, 2a %s, 3a %s -----\n",
                         i, d,  a[j], a[k], a[l] );
        }

        self->suspend();
        
        kill_threads();
        mutex.~Cyg_Mutex();
    }
    CYG_TEST_EXIT( "Control Thread exit" );
}

// ------------------------------------------------------------------------

externC void
cyg_user_start( void )
{ 
    new_thread( control_thread, 0, 2, 1 );
}

#else // CYGVAR_KERNEL_COUNTERS_CLOCK &c

externC void
cyg_start( void )
{
    CYG_TEST_INIT();
    CYG_TEST_PASS_FINISH("Mutex3 test requires:\n"
                         "CYGVAR_KERNEL_COUNTERS_CLOCK &&\n"
                         "(CYGNUM_KERNEL_SCHED_PRIORITIES > 20)\n");
}
#endif // CYGVAR_KERNEL_COUNTERS_CLOCK &c


// ------------------------------------------------------------------------
// Documentation: enclosed is the design of this test.
//
// It has been carefully constructed so that it does NOT use other kernel
// facilities (aside from delay-task) to test that priority inheritance is
// working, or not, as intended by the configuration.
//
// These notes describe the flow of control in one run of the test with the
// ancillary tasks optionally interspersed.  The details of how those extra
// tasks are or are not allowed to run are not described.
// 
// 
// 
// The only change in the test that depends on whether there is inheritance or
// not is the check in thread 2 on "3-ran" and "got it" flags marked ****
// 
// 
// volatile &c booleans:
//         "got it"     = FALSE
//         "3-ran"      = FALSE
//         "3-ended"    = FALSE
//         "extras"[3]  = FALSE
// 
// thread 1.  prio 5, self-suspend.
// 
// thread 1a, prio 8, self-suspend.
// 
// thread 2.  prio 10, self-suspend.
// 
// thread 2a, prio 12, self-suspend.
// 
// thread 3.  prio 15, runs, lock mutex, resume(2)
// 
// thread 3a, prio 17, self-suspend.
// 
//        2.  runs,
//        2.  resume(3a) +++OPTIONAL
//        2.  resume(2a) +++OPTIONAL
//        2.  resume(1a) +++OPTIONAL
//        [1a lock-fail]	thread 3->prio := 8
// 
//        [3. runs maybe, does the looping thing]
// 
//        2.  sleep a while...
// 
//        [2a lock-fail]	thread 3->prio := 12
// 
//        [3. runs maybe, does the looping thing]
// 
//        [3a lock-fail]   thread 3->prio unchanged
// 
//        [3. runs maybe, does the looping thing]
// 
//        2.  lock scheduler
//        2.  set "go-flag"
//        2.  resume(1)
//        2.  resume(1a) +++OPTIONAL
//        2.  resume(2a) +++OPTIONAL
//        2.  resume(3a) +++OPTIONAL
//        2.  unlock scheduler
// 
//        1.  runs, lock mutex - thread 3 has it locked
//
//        2.  busy-waits a bit for thread 3 to come out of its delay() loop.
//            This must be a *busy*wait so that 3 can only run via the
//            inherited raised priority.
// 
//        [xa. all do the same: lock mutex,                ]
//        [xa. unlock mutex                                ]
//        [xa. set a flag "extras"[x] to say we are done.  ]
//        [xa. exit                                        ]
// 
// 
// 
// INHERIT
// -------
// 
//                 thread 3->prio := 5
// 
//        3.  runs,
//        3.  set a flag to say "3-ran",
//        3.  loop with a sleep(1) until "go-flag" is set.
//        3.  check "got it" is false,
//        3.  then unlock mutex,
// 
//                 thread 3->prio := 15
// 
//        1.  runs, set a flag to say "got it",
//        1.  check "3-ended" flag is false
//        1.  unlock mutex,
//        1.  check "3-ended" flag is still false
//        1.  exit.
// 
//        [1a locks, unlocks, exits]
// 
//        2.  runs, check "3-ran" and "got it" flags are TRUE ****
//        2.  check "3-ended" flag is false
//        2.  sleeps for a while so that...
// 
//        [2a locks, unlocks, exits]
//            
//        3.  runs, set "3-ended" flag,
//        3.  check "3-ran" and "got it" flags
//        3.  exit
// 
//        [3a locks, unlocks, exits]
// 
//        2.  awakens, checks all flags true,
//        2.  check that all "extra" threads that we started have indeed run
//        2.  end of test.
// 
// 
// 
// 
// NO-INHERIT
// ----------
//                 thread 1 is waiting on the mutex
// 
//        [1a lock-fail]
// 
//        2.  runs, checks that "3-ran" and "got it" flags are FALSE ****
//        2.  check "3-ended" flag is false
//        2.  sleeps for a while so that...
// 
//        [2a. lock-fail]
//            
//        3.  runs, set a flag to say "3-ran",
//        3.  check "got it" is false,
//        3.  then unlock mutex,
// 
//        1.  runs, set a flag to say "got it",
//        1.  check "3-ended" flag is false
//        1.  unlock mutex,
//        1.  check "3-ended" flag is still false
//        1.  exit.
// 
//        [1a locks, unlocks, exits]
//        [2a locks, unlocks, exits]
// 
//        3.  runs, set "3-ended" flag,
//        3.  check "3-ran" and "got it" flags
//        3.  exit
// 
//        [3a locks, unlocks, exits]
//                
//        2.  awakens, checks all flags true, 
//        2.  check that all "extra" threads that we started have indeed run
//        2.  end of test.
// 
// 
// (the end)
// 
// 
// ------------------------------------------------------------------------

// EOF mutex3.cxx