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Code Issues Releases Wiki Activity

- isc_task_create_bound - create a task bound to specific task queue

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If we know that we'll have a task pool doing specific thing it's better
  to use this knowledge and bind tasks to task queues, this behaves better
  than randomly choosing the task queue.

- use bound resolver tasks - we have a pool of tasks doing resolutions,
  we can spread the load evenly using isc_task_create_bound

- quantum set universally to 25
This commit is contained in:
Witold Kręcicki
2018-11-21 09:50:50 +00:00
committed by Witold Krecicki
parent 54b4e4e61c
commit d5793ecca2
8 changed files with 61 additions and 20 deletions
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55
lib/isc/task.c
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@@ -49,6 +49,10 @@
* state it will stay on the runner it's currently on, if a task is in idle
* state it can be woken up on a specific runner with isc_task_sendto - that
* helps with data locality on CPU.
*
* To make load even some tasks (from task pools) are bound to specific
* queues using isc_task_create_bound. This way load balancing between
* CPUs/queues happens on the higher layer.
*/
#ifdef ISC_TASK_TRACE
@@ -104,6 +108,7 @@ struct isc__task {
char name[16];
void * tag;
unsigned int threadid;
bool bound;
/* Locked by task manager lock. */
LINK(isc__task_t) link;
LINK(isc__task_t) ready_link;
@@ -171,8 +176,7 @@ void
isc__taskmgr_resume(isc_taskmgr_t *manager0);
#define DEFAULT_TASKMGR_QUANTUM 10
#define DEFAULT_DEFAULT_QUANTUM 5
#define DEFAULT_DEFAULT_QUANTUM 25
#define FINISHED(m) ((m)->exiting && EMPTY((m)->tasks))
/*%
@@ -243,7 +247,14 @@ task_finished(isc__task_t *task) {
isc_result_t
isc_task_create(isc_taskmgr_t *manager0, unsigned int quantum,
isc_task_t **taskp)
isc_task_t **taskp)
{
return (isc_task_create_bound(manager0, quantum, taskp, -1));
}
isc_result_t
isc_task_create_bound(isc_taskmgr_t *manager0, unsigned int quantum,
isc_task_t **taskp, int threadid)
{
isc__taskmgr_t *manager = (isc__taskmgr_t *)manager0;
isc__task_t *task;
@@ -257,17 +268,31 @@ isc_task_create(isc_taskmgr_t *manager0, unsigned int quantum,
return (ISC_R_NOMEMORY);
XTRACE("isc_task_create");
task->manager = manager;
task->threadid = atomic_fetch_add_explicit(&manager->curq, 1,
memory_order_relaxed)
% manager->workers;
isc_mutex_init(&task->lock);
if (threadid == -1) {
/*
* Task is not pinned to a queue, it's threadid will be
* choosen when first task will be sent to it - either
* randomly or specified by isc_task_sendto.
*/
task->bound = false;
task->threadid = 0;
} else {
/*
* Task is pinned to a queue, it'll always be run
* by a specific thread.
*/
task->bound = true;
task->threadid = threadid % manager->workers;
}
isc_mutex_init(&task->lock);
task->state = task_state_idle;
task->references = 1;
INIT_LIST(task->events);
INIT_LIST(task->on_shutdown);
task->nevents = 0;
task->quantum = quantum;
task->quantum = (quantum > 0) ? quantum : manager->default_quantum;
task->flags = 0;
task->now = 0;
isc_time_settoepoch(&task->tnow);
@@ -280,11 +305,10 @@ isc_task_create(isc_taskmgr_t *manager0, unsigned int quantum,
exiting = false;
LOCK(&manager->lock);
if (!manager->exiting) {
if (task->quantum == 0)
task->quantum = manager->default_quantum;
APPEND(manager->tasks, task, link);
} else
} else {
exiting = true;
}
UNLOCK(&manager->lock);
if (exiting) {
@@ -490,7 +514,10 @@ isc_task_sendto(isc_task_t *task0, isc_event_t **eventp, int c) {
REQUIRE(VALID_TASK(task));
XTRACE("isc_task_send");
if (c < 0) {
/* If task is bound ignore provided cpu. */
if (task->bound) {
c = task->threadid;
} else if (c < 0) {
c = atomic_fetch_add_explicit(&task->manager->curq, 1,
memory_order_relaxed);
}
@@ -540,7 +567,9 @@ isc_task_sendtoanddetach(isc_task_t **taskp, isc_event_t **eventp, int c) {
REQUIRE(VALID_TASK(task));
XTRACE("isc_task_sendanddetach");
if (c < 0) {
if (task->bound) {
c = task->threadid;
} else if (c < 0) {
c = atomic_fetch_add_explicit(&task->manager->curq, 1,
memory_order_relaxed);
}