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//==========================================================================
//
// sync3.cxx
//
// Sync test 3 -- tests priorities and priority inheritance
//
//==========================================================================
// ####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
//
// eCos is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 or (at your option) any later
// version.
//
// eCos is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License
// along with eCos; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
//
// As a special exception, if other files instantiate templates or use
// macros or inline functions from this file, or you compile this file
// and link it with other works to produce a work based on this file,
// this file does not by itself cause the resulting work to be covered by
// the GNU General Public License. However the source code for this file
// must still be made available in accordance with section (3) of the GNU
// General Public License v2.
//
// This exception does not invalidate any other reasons why a work based
// on this file might be covered by the GNU General Public License.
// -------------------------------------------
// ####ECOSGPLCOPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s): dsm
// Contributors: dsm
// Date: 1998-02-18
// Description:
// Creates mutexes and threads to set up starvation condition.
// Checks simple priority inheritance cures this.
//
// The starvation condition is caused by the highest priority
// thread, t0 waiting on a mutex which is never released because
// it is held by t2. t2 never releases it because t1 will be
// running at a priority level higher than t2 (but lower than t0).
//
// With priority inheritance enabled, t2 will inherit its priority
// from t0 when t0 tries to grab the mutex.
//
// Options:
// CYGIMP_THREAD_PRIORITY
// CYGSEM_KERNEL_SYNCH_MUTEX_PRIORITY_INVERSION_PROTOCOL_INHERIT
// CYGSEM_KERNEL_SYNCH_MUTEX_PRIORITY_INVERSION_PROTOCOL_SIMPLE
//####DESCRIPTIONEND####
#include <pkgconf/kernel.h>
#include <cyg/kernel/thread.hxx>
#include <cyg/kernel/thread.inl>
#include <cyg/kernel/sched.hxx>
#include <cyg/kernel/mutex.hxx>
#include <cyg/kernel/sema.hxx>
#include <cyg/infra/testcase.h>
#include <cyg/kernel/sched.inl>
#if defined(CYGIMP_THREAD_PRIORITY) && \
!defined(CYGPKG_KERNEL_SMP_SUPPORT)
// ------------------------------------------------------------------------
// Manufacture a simpler feature test macro for priority inheritance than
// the configuration gives us. We have priority inheritance if it is configured
// as the only protocol, or if it is the default protocol for dynamic protocol
// choice.
// FIXME: If we have dynamic protocol choice, we can also set priority inheritance
// as the protocol to be used on the mutexes we are interested in. At present we
// do not do this.
#ifdef CYGSEM_KERNEL_SYNCH_MUTEX_PRIORITY_INVERSION_PROTOCOL_INHERIT
# ifdef CYGSEM_KERNEL_SYNCH_MUTEX_PRIORITY_INVERSION_PROTOCOL_DYNAMIC
# ifdef CYGSEM_KERNEL_SYNCH_MUTEX_PRIORITY_INVERSION_PROTOCOL_DEFAULT_INHERIT
# define PRIORITY_INHERITANCE
# else
# undef PRIORITY_INHERITANCE
# endif
# else
# define PRIORITY_INHERITANCE
# endif
#else
# undef PRIORITY_INHERITANCE
#endif
// ------------------------------------------------------------------------
#define NTHREADS 3
#include "testaux.hxx"
static Cyg_Mutex m0;
static Cyg_Binary_Semaphore s0, s1, s2;
static cyg_ucount8 m0d = 9;
static void check_priorities_normal()
{
CHECK( 5 == thread[0]->get_priority());
CHECK( 6 == thread[1]->get_priority());
CHECK( 7 == thread[2]->get_priority());
}
static void check_priorities_inherited()
{
CHECK( 5 == thread[0]->get_priority());
CHECK( 6 == thread[1]->get_priority());
#ifdef PRIORITY_INHERITANCE
CHECK( 5 == thread[2]->get_current_priority());
#endif
CHECK( 7 == thread[2]->get_priority());
}
static void entry0( CYG_ADDRWORD data )
{
s0.wait(); // wait until t2 has gained m0.lock
check_priorities_normal();
m0.lock(); {
check_priorities_normal();
CHECK( 2 == m0d );
m0d = 0;
} m0.unlock();
check_priorities_normal();
#ifdef PRIORITY_INHERITANCE
CYG_TEST_PASS_FINISH("Sync 3 OK -- priority inheritance worked");
#else
CYG_TEST_FAIL_FINISH("Sync 3: thread not starved");
#endif
// NOT REACHED
}
static void entry1( CYG_ADDRWORD data )
{
s1.wait();
// The delay below will allow testing of the priority inheritance
// mechanism when scheduler does not guarantee to schedule threads
// in strict priority order.
for ( volatile cyg_ucount32 i=0; i < 100000; i++ )
; // math is hard
#ifdef PRIORITY_INHERITANCE
// thread0 should have stopped by this point
CYG_TEST_FAIL_FINISH("Sync 3: priority inheritance mechanism failed");
#else
// With strict priority scheduling and no priority inheritance
// this is expected to happen.
CYG_TEST_PASS_FINISH("Sync 3 OK");
#endif
CYG_TEST_FAIL_FINISH("Not reached");
}
void entry2( CYG_ADDRWORD data )
{
m0.lock(); {
CHECK( 9 == m0d );
check_priorities_normal();
s0.post(); // Now I have lock on m0, wake t0 then t1
check_priorities_inherited();
s1.post();
check_priorities_inherited();
m0d = 2;
} m0.unlock();
check_priorities_normal();
m0.lock(); {
check_priorities_normal();
CHECK( 0 == m0d );
m0d = 21;
s2.wait(); // never posted
} m0.unlock();
}
void sync3_main(void)
{
CYG_TEST_INIT();
new_thread( entry0, 0);
new_thread( entry1, 1);
new_thread( entry2, 2);
thread[0]->set_priority(5);
thread[1]->set_priority(6);
thread[2]->set_priority(7);
Cyg_Scheduler::start();
CYG_TEST_FAIL_FINISH("Not reached");
}
externC void
cyg_start( void )
{
#ifdef CYGSEM_HAL_STOP_CONSTRUCTORS_ON_FLAG
cyg_hal_invoke_constructors();
#endif
sync3_main();
}
#else // defined(CYGIMP_THREAD_PRIORITY) etc
externC void
cyg_start( void )
{
CYG_TEST_INIT();
CYG_TEST_INFO("Sync3 test requires:\n"
"defined(CYGIMP_THREAD_PRIORITY) &&\n"
"!defined(CYGPKG_KERNEL_SMP_SUPPORT)\n");
CYG_TEST_NA("Sync3 test requirements");
}
#endif // defined(CYGIMP_THREAD_PRIORITY) etc
// EOF sync3.cxx
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