MINOR: tasks: add a mask of the queues with active tasklets
It is neither convenient nor scalable to check each and every tasklet
queue to figure whether it's empty or not while we often need to check
them all at once. This patch introduces a tasklet class mask which gets
a bit 1 set for each queue representing one class of service. A single
test on the mask allows to figure whether there's still some work to be
done. It will later be usable to better factor the runqueue code.
Bits are set when tasklets are queued. They're cleared when queues are
emptied. It is possible that a queue is empty but has a bit if a tasklet
was added then removed, but this is not a problem as this is properly
checked for in run_tasks_from_list().
diff --git a/include/haproxy/task-t.h b/include/haproxy/task-t.h
index 334547b..88f2bdd 100644
--- a/include/haproxy/task-t.h
+++ b/include/haproxy/task-t.h
@@ -78,6 +78,7 @@
int rqueue_size; /* Number of elements in the per-thread run queue */
struct task *current; /* current task (not tasklet) */
int current_queue; /* points to current tasklet list being run, -1 if none */
+ uint8_t tl_class_mask; /* bit mask of non-empty tasklets classes */
__attribute__((aligned(64))) char end[0];
};
diff --git a/include/haproxy/task.h b/include/haproxy/task.h
index acfa2c3..3a56acd 100644
--- a/include/haproxy/task.h
+++ b/include/haproxy/task.h
@@ -166,9 +166,7 @@
{
return (!!(global_tasks_mask & tid_bit) |
(sched->rqueue_size > 0) |
- !LIST_ISEMPTY(&sched->tasklets[TL_URGENT]) |
- !LIST_ISEMPTY(&sched->tasklets[TL_NORMAL]) |
- !LIST_ISEMPTY(&sched->tasklets[TL_BULK]) |
+ !!sched->tl_class_mask |
!MT_LIST_ISEMPTY(&sched->shared_tasklet_list));
}
@@ -330,16 +328,20 @@
if (LIST_ISEMPTY(&tl->list)) {
if (tl->state & TASK_SELF_WAKING) {
LIST_ADDQ(&sched->tasklets[TL_BULK], &tl->list);
+ sched->tl_class_mask |= 1 << TL_BULK;
}
else if ((struct task *)tl == sched->current) {
_HA_ATOMIC_OR(&tl->state, TASK_SELF_WAKING);
LIST_ADDQ(&sched->tasklets[TL_BULK], &tl->list);
+ sched->tl_class_mask |= 1 << TL_BULK;
}
else if (sched->current_queue < 0) {
LIST_ADDQ(&sched->tasklets[TL_URGENT], &tl->list);
+ sched->tl_class_mask |= 1 << TL_URGENT;
}
else {
LIST_ADDQ(&sched->tasklets[sched->current_queue], &tl->list);
+ sched->tl_class_mask |= 1 << sched->current_queue;
}
_HA_ATOMIC_ADD(&tasks_run_queue, 1);
diff --git a/src/task.c b/src/task.c
index 1bb2ce4..d6bda26 100644
--- a/src/task.c
+++ b/src/task.c
@@ -452,17 +452,17 @@
max[TL_URGENT] = max[TL_NORMAL] = max[TL_BULK] = 0;
/* urgent tasklets list gets a default weight of ~50% */
- if (!LIST_ISEMPTY(&tt->tasklets[TL_URGENT]) ||
+ if ((tt->tl_class_mask & (1 << TL_URGENT)) ||
!MT_LIST_ISEMPTY(&tt->shared_tasklet_list))
max[TL_URGENT] = default_weights[TL_URGENT];
/* normal tasklets list gets a default weight of ~37% */
- if (!LIST_ISEMPTY(&tt->tasklets[TL_NORMAL]) ||
+ if ((tt->tl_class_mask & (1 << TL_NORMAL)) ||
(sched->rqueue_size > 0) || (global_tasks_mask & tid_bit))
max[TL_NORMAL] = default_weights[TL_NORMAL];
/* bulk tasklets list gets a default weight of ~13% */
- if (!LIST_ISEMPTY(&tt->tasklets[TL_BULK]))
+ if ((tt->tl_class_mask & (1 << TL_BULK)))
max[TL_BULK] = default_weights[TL_BULK];
/* Now compute a fair share of the weights. Total may slightly exceed
@@ -530,6 +530,7 @@
LIST_INIT(&((struct tasklet *)t)->list);
/* And add it to the local task list */
tasklet_insert_into_tasklet_list(&tt->tasklets[TL_NORMAL], (struct tasklet *)t);
+ tt->tl_class_mask |= 1 << TL_NORMAL;
tt->task_list_size++;
activity[tid].tasksw++;
}
@@ -544,8 +545,11 @@
* main list.
*/
tmp_list = MT_LIST_BEHEAD(&tt->shared_tasklet_list);
- if (tmp_list)
+ if (tmp_list) {
LIST_SPLICE_END_DETACHED(&tt->tasklets[TL_URGENT], (struct list *)tmp_list);
+ if (!LIST_ISEMPTY(&tt->tasklets[TL_URGENT]))
+ tt->tl_class_mask |= 1 << TL_URGENT;
+ }
/* execute tasklets in each queue */
for (queue = 0; queue < TL_CLASSES; queue++) {
@@ -553,6 +557,8 @@
tt->current_queue = queue;
max_processed -= run_tasks_from_list(&tt->tasklets[queue], max[queue]);
tt->current_queue = -1;
+ if (LIST_ISEMPTY(&tt->tasklets[queue]))
+ tt->tl_class_mask &= ~(1 << queue);
}
}
@@ -560,9 +566,7 @@
if (max_processed > 0 && thread_has_tasks())
goto not_done_yet;
- if (!LIST_ISEMPTY(&sched->tasklets[TL_URGENT]) |
- !LIST_ISEMPTY(&sched->tasklets[TL_NORMAL]) |
- !LIST_ISEMPTY(&sched->tasklets[TL_BULK]))
+ if (tt->tl_class_mask)
activity[tid].long_rq++;
}