preempt: introduce idle process; timer: use managed irqs for preemption
authorbernie <bernie@38d2e660-2303-0410-9eaa-f027e97ec537>
Wed, 20 Aug 2008 19:46:33 +0000 (19:46 +0000)
committerbernie <bernie@38d2e660-2303-0410-9eaa-f027e97ec537>
Wed, 20 Aug 2008 19:46:33 +0000 (19:46 +0000)
git-svn-id: https://src.develer.com/svnoss/bertos/trunk@1665 38d2e660-2303-0410-9eaa-f027e97ec537

bertos/drv/timer.c
bertos/drv/timer.h
bertos/emul/timer_posix.c
bertos/kern/irq.c
bertos/kern/preempt.c
bertos/kern/signal.c

index f282478aa361a42e77e69762ffab5f8fbabbf968..485cc0229d2192796b6c2cfe2d1ae630654a9984 100644 (file)
@@ -54,7 +54,8 @@
  * Try the CPU specific one for bare-metal environments.
  */
 #if OS_HOSTED
-       #include OS_CSOURCE(timer)
+       //#include OS_CSOURCE(timer)
+       #include <emul/timer_posix.c>
 #else
        #include CPU_CSOURCE(timer)
 #endif
index 41f43f655d5cc191201fd0c7c8fa1736d334c965..6ae1907e6863ca5b2e182b694811e5a1eaab25c0 100644 (file)
@@ -51,7 +51,8 @@
  * Try the CPU specific one for bare-metal environments.
  */
 #if OS_HOSTED
-       #include OS_HEADER(timer)
+       //#include OS_HEADER(timer)
+       #include <emul/timer_posix.h>
 #else
        #include CPU_HEADER(timer)
 #endif
index ede534063a3fd05100acebe729dc5ed2b18a02ae..d54c61205c33c73c5b78ce2915eb80b2f280ae96 100644 (file)
  * Copyright 2005, 2008 Develer S.r.l. (http://www.develer.com/)
  * -->
  *
- * \version $Id$
+ * \brief Low-level timer module for Qt emulator (implementation).
  *
+ * \version $Id$
  * \author Bernie Innocenti <bernie@codewiz.org>
- * \brief Low-level timer module for Qt emulator (implementation).
  */
-#include <cfg/compiler.h> // hptime.t
+//#include <cfg/compiler.h> // hptime.t
 #include <os/hptime.h>
+#include <kern/irq.h>     // irq_register()
 
+#if !CONFIG_KERN_IRQ
 #include <signal.h>       // sigaction()
-#include <sys/time.h>     // setitimer()
 #include <string.h>       // memset()
+#endif
+#include <sys/time.h>     // setitimer()
 
 
 // Forward declaration for the user interrupt server routine.
@@ -48,19 +51,19 @@ void timer_isr(int);
 /// HW dependent timer initialization.
 static void timer_hw_init(void)
 {
-#if CONFIG_KERN_IRQ
-       irq_register(SIGALRM, timer_isr);
-#else // ! CONFIG_KERN_IRQ
-       struct sigaction sa;
-       memset(&sa, 0, sizeof(sa));
+       #if CONFIG_KERN_IRQ
+               irq_register(SIGALRM, (void (*)(void))timer_isr);
+       #else // ! CONFIG_KERN_IRQ
+               struct sigaction sa;
+               memset(&sa, 0, sizeof(sa));
 
-       // Setup interrupt callback
-       sa.sa_handler = timer_isr;
-       sigemptyset(&sa.sa_mask);
-       sigaddset(&sa.sa_mask, SIGALRM);
-       sa.sa_flags = SA_RESTART;
-       sigaction(SIGALRM, &sa, NULL);
-#endif // CONFIG_KERN_IRQ
+               // Setup interrupt callback
+               sa.sa_handler = timer_isr;
+               sigemptyset(&sa.sa_mask);
+               sigaddset(&sa.sa_mask, SIGALRM);
+               sa.sa_flags = SA_RESTART;
+               sigaction(SIGALRM, &sa, NULL);
+       #endif // CONFIG_KERN_IRQ
 
        // Setup POSIX realtime timer to interrupt every 1/TIMER_TICKS_PER_SEC.
        static const struct itimerval itv =
index 23d19afac0ea76fb14abac4e87170822eb714807..9b87d69b25420b03798c027adad670524a1ff65f 100644 (file)
@@ -57,29 +57,22 @@ void irq_entry(int signum)
        irq_handlers[signum]();
 
 #if CONFIG_KERN_PREEMPT
-       if (!CurrentProcess)
-       {
-               TRACEMSG("no runnable processes!");
-               IRQ_ENABLE;
-               pause();
-       }
-       else
+       ASSERT2(CurrentProcess, "no idle proc?");
+
+       if (old_process != CurrentProcess)
        {
-               if (old_process != CurrentProcess)
-               {
-                       TRACEMSG("switching from %p:%s to %p:%s",
-                               old_process, old_process ? old_process->monitor.name : "-",
-                               CurrentProcess, CurrentProcess->monitor.name);
-
-                       if (old_process)
-                               swapcontext(&old_process->context, &CurrentProcess->context);
-                       else
-                               setcontext(&CurrentProcess->context);
-
-                       // not reached
-               }
-               TRACEMSG("keeping %p:%s", CurrentProcess, CurrentProcess->monitor.name);
+               TRACEMSG("switching from %p:%s to %p:%s",
+                       old_process, old_process ? old_process->monitor.name : "---",
+                       CurrentProcess, CurrentProcess->monitor.name);
+
+               if (old_process)
+                       swapcontext(&old_process->context, &CurrentProcess->context);
+               else
+                       setcontext(&CurrentProcess->context);
+
+               // not reached
        }
+       //TRACEMSG("keeping %p:%s", CurrentProcess, CurrentProcess->monitor.name);
 #endif // CONFIG_KERN_PREEMPT
 }
 
@@ -97,9 +90,7 @@ void irq_init(void)
        act.sa_flags = SA_RESTART; // | SA_SIGINFO;
 
        sigaction(SIGUSR1, &act, NULL);
-       #if !(ARCH & ARCH_QT)
-               sigaction(SIGALRM, &act, NULL);
-       #endif
+       sigaction(SIGALRM, &act, NULL);
 
        MOD_INIT(irq);
 }
index 9af6c0d1b402a973cc144532c15c2f1ae5d15d2f..7ecd481d0cdf57c6d4c3679fc4ccfa43f5cc794e 100644 (file)
@@ -29,8 +29,7 @@
  * Copyright 2008 Bernie Innocenti <bernie@codewiz.org>
  * -->
  *
- * \brief Simple realtime multitasking scheduler.
- *        Context switching is only done cooperatively.
+ * \brief Simple preemptive multitasking scheduler.
  *
  * \version $Id: proc.c 1616 2008-08-10 19:41:26Z bernie $
  * \author Bernie Innocenti <bernie@codewiz.org>
 #include "proc.h"
 
 #include <kern/irq.h>
+#include <kern/monitor.h>
 #include <cpu/frame.h> // CPU_IDLE
 #include <drv/timer.h>
 #include <cfg/module.h>
 
 
-/*
- * The time sharing scheduler forces a task switch when the current
- * process has exhausted its quantum.
- */
-uint16_t Quantum;
 
 Timer preempt_timer;
 
@@ -87,48 +82,31 @@ void proc_permit(void)
 
 void proc_preempt(void)
 {
-       TRACE;
+       IRQ_DISABLE;
 
-       ATOMIC(LIST_ASSERT_VALID(&ProcReadyList));
+       LIST_ASSERT_VALID(&ProcReadyList);
+       CurrentProcess = (struct Process *)list_remHead(&ProcReadyList);
+       LIST_ASSERT_VALID(&ProcReadyList);
+       ASSERT2(CurrentProcess, "no idle proc?");
 
-       TRACEMSG("hello1");
-       IRQ_DISABLE;
-       /* Poll on the ready queue for the first ready process */
-       while (!(CurrentProcess = (struct Process *)list_remHead(&ProcReadyList)))
-       {
-       //TRACEMSG("hello2");
-               /*
-                * Make sure we physically reenable interrupts here, no matter what
-                * the current task status is. This is important because if we
-                * are idle-spinning, we must allow interrupts, otherwise no
-                * process will ever wake up.
-                *
-                * During idle-spinning, an interrupt can occur and it may
-                * modify \p ProcReadyList. To ensure that compiler reload this
-                * variable every while cycle we call CPU_MEMORY_BARRIER.
-                * The memory barrier ensure that all variables used in this context
-                * are reloaded.
-                */
-               IRQ_ENABLE;
-               //FIXME: calls Qt stuff from sighandler! CPU_IDLE;
-               MEMORY_BARRIER;
-               IRQ_DISABLE;
-       //TRACEMSG("hello3");
-       }
        IRQ_ENABLE;
-       TRACEMSG("hello4");
+
+       TRACEMSG("new proc: %p:%s", CurrentProcess, CurrentProcess ? CurrentProcess->monitor.name : "---");
+       monitor_report();
 }
 
 void proc_preempt_timer(UNUSED_ARG(void *, param))
 {
        IRQ_DISABLE;
-       if (CurrentProcess)
+/*
+       if (!CurrentProcess->forbid_cnt)
        {
                TRACEMSG("preempting %p:%s", CurrentProcess, CurrentProcess->monitor.name);
+               LIST_ASSERT_VALID(&ProcReadyList);
                SCHED_ENQUEUE(CurrentProcess);
-               IRQ_ENABLE;
                proc_preempt();
        }
+*/
        IRQ_ENABLE;
 
        timer_setDelay(&preempt_timer, CONFIG_KERN_QUANTUM);
@@ -145,9 +123,14 @@ void proc_schedule(void)
 
 void proc_yield(void)
 {
-       ATOMIC(SCHED_ENQUEUE(CurrentProcess));
+       TRACE;
 
+       ASSERT_IRQ_ENABLED();
+       IRQ_DISABLE;
+       SCHED_ENQUEUE(CurrentProcess);
+       LIST_ASSERT_VALID(&ProcReadyList);
        proc_schedule();
+       IRQ_ENABLE;
 }
 
 void proc_entry(void (*user_entry)(void))
@@ -156,6 +139,29 @@ void proc_entry(void (*user_entry)(void))
        proc_exit();
 }
 
+
+static cpustack_t idle_stack[CONFIG_PROC_DEFSTACKSIZE / sizeof(cpustack_t)];
+
+/*
+ * The idle process
+ *
+ * This process never dies and never sleeps.  It's also quite apathic
+ * and a bit antisocial.
+ *
+ * Having an idle process costs some stack space, but simplifies the
+ * interrupt-driven preemption logic because there is always a user
+ * context to which we can return.
+ */
+static NORETURN void idle(void)
+{
+       for (;;)
+       {
+               TRACE;
+               monitor_report();
+               proc_yield(); // FIXME: CPU_IDLE
+       }
+}
+
 void preempt_init(void)
 {
        MOD_CHECK(irq);
@@ -166,4 +172,6 @@ void preempt_init(void)
        timer_setSoftint(&preempt_timer, proc_preempt_timer, NULL);
        timer_setDelay(&preempt_timer, CONFIG_KERN_QUANTUM);
        timer_add(&preempt_timer);
+
+       proc_new(idle, NULL, sizeof(idle_stack), idle_stack);
 }
index d7633a147809b582c64b2e300489ac2917658b12..4333fa7937fe251a91ee2a0c5bdb1e4120d35006 100644 (file)
@@ -28,7 +28,6 @@
  *
  * Copyright 2004, 2008 Develer S.r.l. (http://www.develer.com/)
  * Copyright 1999, 2000, 2001 Bernie Innocenti <bernie@codewiz.org>
- *
  * -->
  *
  * \brief IPC signals implementation.
@@ -96,7 +95,6 @@
  *    timer_delayTickes().
  *
  * \version $Id$
- *
  * \author Bernie Innocenti <bernie@codewiz.org>
  */
 
 #include <drv/timer.h>
 #include <kern/proc.h>
 #include <kern/proc_p.h>
+
 
 #if CONFIG_KERN_SIGNALS