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* The loop that should select a thread of the next priority class actually did

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not work; it would always choose the last thread of the current priority.
  IOW a thread was never skipped, and lower priority threads were never called
  when a higher priority thread was running - from the POV of the scheduler,
  we only has real time threads...
* Improved "run_queue" KDL output.
* Minor cleanup.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22515 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler 2007-10-12 10:29:08 +00:00
parent 00ef60f643
commit 4ff0c50078
1 changed files with 25 additions and 29 deletions
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54
src/system/kernel/scheduler.cpp
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@ -7,7 +7,7 @@
* Distributed under the terms of the NewOS License.
*/
/* The thread scheduler */
/*! The thread scheduler */
#include <OS.h>
@ -30,10 +30,6 @@
#endif
// prototypes
static int dump_run_queue(int argc, char **argv);
static int _rand(void);
// The run queue. Holds the threads ready to run ordered by priority.
static struct thread *sRunQueue = NULL;
@ -58,10 +54,12 @@ dump_run_queue(int argc, char **argv)
thread = sRunQueue;
if (!thread)
dprintf("Run queue is empty!\n");
kprintf("Run queue is empty!\n");
else {
kprintf("thread id priority name\n");
while (thread) {
dprintf("Thread id: %ld - priority: %ld\n", thread->id, thread->priority);
kprintf("%p %-7ld %-8ld %s\n", thread, thread->id,
thread->priority, thread->name);
thread = thread->queue_next;
}
}
@ -70,10 +68,9 @@ dump_run_queue(int argc, char **argv)
}
/** Enqueues the thread into the run queue.
* Note: thread lock must be held when entering this function
*/
/*! Enqueues the thread into the run queue.
Note: thread lock must be held when entering this function
*/
void
scheduler_enqueue_in_run_queue(struct thread *thread)
{
@ -98,17 +95,17 @@ scheduler_enqueue_in_run_queue(struct thread *thread)
}
/** Removes a thread from the run queue.
* Note: thread lock must be held when entering this function
*/
/*! Removes a thread from the run queue.
Note: thread lock must be held when entering this function
*/
void
scheduler_remove_from_run_queue(struct thread *thread)
{
struct thread *item, *prev;
// find thread in run queue
for (item = sRunQueue, prev = NULL; item && item != thread; item = item->queue_next) {
for (item = sRunQueue, prev = NULL; item && item != thread;
item = item->queue_next) {
if (prev)
prev = prev->queue_next;
else
@ -145,10 +142,9 @@ reschedule_event(timer *unused)
}
/** Runs the scheduler.
* Note: expects thread spinlock to be held
*/
/*! Runs the scheduler.
Note: expects thread spinlock to be held
*/
void
scheduler_reschedule(void)
{
@ -206,17 +202,18 @@ scheduler_reschedule(void)
if (nextThread->queue_next && nextThread->queue_next->priority == B_IDLE_PRIORITY)
break;
// skip normal threads sometimes (roughly 16%)
if (_rand() > 0x2000)
// skip normal threads sometimes (roughly 20%)
if (_rand() > 0x1a00)
break;
// skip until next lower priority
int32 priority = nextThread->priority;
while (nextThread->queue_next && priority == nextThread->queue_next->priority
&& nextThread->queue_next->priority > B_IDLE_PRIORITY) {
do {
prevThread = nextThread;
nextThread = nextThread->queue_next;
}
} while (nextThread->queue_next != NULL
&& priority == nextThread->queue_next->priority
&& nextThread->queue_next->priority > B_IDLE_PRIORITY);
}
}
@ -273,10 +270,9 @@ scheduler_init(void)
}
/** This starts the scheduler. Must be run under the context of
* the initial idle thread.
*/
/*! This starts the scheduler. Must be run under the context of
the initial idle thread.
*/
void
scheduler_start(void)
{