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[kernel][thread] Allow pinning threads to a specific cpu

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The existing runqueues are scanned on resched until a thread that is
not pinned to another cpu is found.

Per-pu runqueues can be added later to avoid this scan.

Change-Id: Idd7dbddb4b79ef38a0ccd0c42b53f8867020e6cd

Conflicts:
	kernel/thread.c
This commit is contained in:
Arve Hjønnevåg
2015-01-23 19:38:43 -08:00
committed by Travis Geiselbrecht
parent 888ecb3e33
commit 794d304599
3 changed files with 35 additions and 12 deletions
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45
kernel/thread.c
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@@ -112,6 +112,7 @@ static void init_thread_struct(thread_t *t, const char *name)
{
memset(t, 0, sizeof(thread_t));
t->magic = THREAD_MAGIC;
t->pinned_cpu = -1;
strlcpy(t->name, name, sizeof(t->name));
}
@@ -424,6 +425,31 @@ static void idle_thread_routine(void)
arch_idle();
}
static thread_t *get_top_thread(int cpu)
{
thread_t *newthread;
uint32_t local_run_queue_bitmap = run_queue_bitmap;
int next_queue;
while (local_run_queue_bitmap) {
next_queue = HIGHEST_PRIORITY - __builtin_clz(local_run_queue_bitmap) - (32 - NUM_PRIORITIES);
list_for_every_entry(&run_queue[next_queue], newthread, thread_t, queue_node) {
if (newthread->pinned_cpu < 0 || newthread->pinned_cpu == cpu) {
list_delete(&newthread->queue_node);
if (list_is_empty(&run_queue[next_queue]))
run_queue_bitmap &= ~(1<<next_queue);
return newthread;
}
}
local_run_queue_bitmap &= ~(1<<next_queue);
}
return NULL;
}
/**
* @brief Cause another thread to be executed.
*
@@ -450,16 +476,8 @@ void thread_resched(void)
THREAD_STATS_INC(reschedules);
if (likely(run_queue_bitmap != 0)) {
/* find the first queue with a thread in it */
uint next_queue = HIGHEST_PRIORITY - __builtin_clz(run_queue_bitmap)
- (sizeof(run_queue_bitmap) * 8 - NUM_PRIORITIES);
newthread = list_remove_head_type(&run_queue[next_queue], thread_t, queue_node);
if (list_is_empty(&run_queue[next_queue]))
run_queue_bitmap &= ~(1U << next_queue);
} else {
newthread = get_top_thread(cpu);
if (unlikely(!newthread)) {
/* no threads to run, select the idle thread for this cpu */
newthread = &idle_threads[cpu];
}
@@ -746,6 +764,7 @@ void thread_init_early(void)
t->state = THREAD_RUNNING;
t->flags = THREAD_FLAG_DETACHED;
t->curr_cpu = 0;
t->pinned_cpu = 0;
wait_queue_init(&t->retcode_wait_queue);
list_add_head(&thread_list, &t->thread_list_node);
set_current_thread(t);
@@ -818,6 +837,7 @@ void thread_become_idle(void)
/* mark ourself as idle */
t->priority = IDLE_PRIORITY;
t->flags |= THREAD_FLAG_IDLE;
t->pinned_cpu = arch_curr_cpu_num();
mp_set_curr_cpu_active(true);
mp_set_cpu_idle(arch_curr_cpu_num());
@@ -847,6 +867,7 @@ void thread_secondary_cpu_entry(void)
t->state = THREAD_RUNNING;
t->flags = THREAD_FLAG_DETACHED | THREAD_FLAG_IDLE;
t->curr_cpu = cpu;
t->pinned_cpu = cpu;
wait_queue_init(&t->retcode_wait_queue);
THREAD_LOCK(state);
@@ -885,8 +906,8 @@ static const char *thread_state_to_str(enum thread_state state)
void dump_thread(thread_t *t)
{
dprintf(INFO, "dump_thread: t %p (%s)\n", t, t->name);
dprintf(INFO, "\tstate %s, curr_cpu %d, priority %d, remaining quantum %d\n",
thread_state_to_str(t->state), t->curr_cpu, t->priority, t->remaining_quantum);
dprintf(INFO, "\tstate %s, curr_cpu %d, pinned_cpu %d, priority %d, remaining quantum %d\n",
thread_state_to_str(t->state), t->curr_cpu, t->pinned_cpu, t->priority, t->remaining_quantum);
dprintf(INFO, "\tstack %p, stack_size %zd\n", t->stack, t->stack_size);
dprintf(INFO, "\tentry %p, arg %p, flags 0x%x\n", t->entry, t->arg, t->flags);
dprintf(INFO, "\twait queue %p, wait queue ret %d\n", t->blocking_wait_queue, t->wait_queue_block_ret);