Commit 60b655aa authored by Tomasz Zawadzki's avatar Tomasz Zawadzki Committed by Jim Harris
Browse files

scheduler_dynamic: simplify thread balancing logic 



When picking a path to go down with a thread,
conditions unnecessarily piled up.

Instead do it either of two ways:
- move idle threads to main core
- find best core for active threads and move them there

There is no need to worry about cpumask of the thread,
since _find_optimal_core() will always return a core
within the cpumask.

If the found core is the same one as the current,
_move_thread() won't perform any action.

Signed-off-by: default avatarTomasz Zawadzki <tomasz.zawadzki@intel.com>
Change-Id: I0f4782766c15c86b5db0c970cfc9547058845b2a
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/8065


Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: default avatarShuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
parent 76b72102

lib/event/scheduler_dynamic.c

+4 −12
Original line number Diff line number Diff line
@@ -194,9 +194,7 @@ balance(struct spdk_scheduler_core_info *cores_info, int cores_count, 
{

	struct spdk_reactor *reactor;

	struct spdk_lw_thread *lw_thread;

	struct spdk_thread *thread;

	struct spdk_scheduler_core_info *core;

	struct spdk_cpuset *cpumask;

	struct core_stats *main_core;

	uint32_t target_lcore;

	uint32_t i, j;
@@ -217,19 +215,13 @@ balance(struct spdk_scheduler_core_info *cores_info, int cores_count, 


		for (j = 0; j < core->threads_count; j++) {

			lw_thread = core->threads[j];

			thread = spdk_thread_get_from_ctx(lw_thread);

			cpumask = spdk_thread_get_cpumask(thread);

			load = _get_thread_load(lw_thread);



			if (i == g_main_lcore && load >= SCHEDULER_LOAD_LIMIT) {

				/* This thread is active and on the main core, we need to pick a core to move it to */

				target_lcore = _find_optimal_core(lw_thread);

				_move_thread(lw_thread, target_lcore);

			} else if (i != g_main_lcore && load < SCHEDULER_LOAD_LIMIT) {

				/* This thread is idle but not on the main core, so we need to move it to the main core */

			if (load < SCHEDULER_LOAD_LIMIT) {

				/* This thread is idle, move it to the main core. */

				_move_thread(lw_thread, g_main_lcore);

			} else if (i != g_main_lcore && !spdk_cpuset_get_cpu(cpumask, i)) {

				/* Move busy thread only if cpumask does not match current core (except main core) */

			} else {

				/* This thread is active. */

				target_lcore = _find_optimal_core(lw_thread);

				_move_thread(lw_thread, target_lcore);

			}