Commit 86a21aee authored by Ben Walker's avatar Ben Walker Committed by Jim Harris
Browse files

event: Implement context switch monitor without a poller 



This is much simpler and avoids the problems with requiring
it to run on a thread.

Change-Id: I811444c5a15d292356703beccc17e505d55d7678
Signed-off-by: default avatarBen Walker <benjamin.walker@intel.com>
Reviewed-on: https://review.gerrithub.io/c/443645


Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
Reviewed-by: default avatarShuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
parent 3569ea15

lib/event/reactor.c

+18 −48
Original line number Diff line number Diff line
@@ -162,10 +162,11 @@ _spdk_event_queue_run_batch(struct spdk_reactor *reactor, struct spdk_thread *th 
	return count;

}



#define CONTEXT_SWITCH_MONITOR_PERIOD 1000000



static int

get_rusage(void *arg)

get_rusage(struct spdk_reactor *reactor)

{

	struct spdk_reactor	*reactor = arg;

	struct rusage		rusage;



	if (getrusage(RUSAGE_THREAD, &rusage) != 0) {
@@ -183,46 +184,14 @@ get_rusage(void *arg) 
	return -1;

}



static void

_spdk_reactor_context_switch_monitor_start(void *arg1, void *arg2)

{

	struct spdk_reactor *reactor = arg1;



	if (reactor->rusage_poller == NULL) {

		getrusage(RUSAGE_THREAD, &reactor->rusage);

		reactor->rusage_poller = spdk_poller_register(get_rusage, reactor, 1000000);

	}

}



static void

_spdk_reactor_context_switch_monitor_stop(void *arg1, void *arg2)

{

	struct spdk_reactor *reactor = arg1;



	if (reactor->rusage_poller != NULL) {

		spdk_poller_unregister(&reactor->rusage_poller);

	}

}



void

spdk_reactor_enable_context_switch_monitor(bool enable)

{

	struct spdk_reactor *reactor;

	spdk_event_fn fn;

	uint32_t core;



	if (enable != g_context_switch_monitor_enabled) {

	/* This global is being read by multiple threads, so this isn't

	 * strictly thread safe. However, we're toggling between true and

	 * false here, and if a thread sees the value update later than it

	 * should, it's no big deal. */

	g_context_switch_monitor_enabled = enable;

		if (enable) {

			fn = _spdk_reactor_context_switch_monitor_start;

		} else {

			fn = _spdk_reactor_context_switch_monitor_stop;

		}

		SPDK_ENV_FOREACH_CORE(core) {

			reactor = spdk_reactor_get(core);

			spdk_event_call(spdk_event_allocate(core, fn, reactor, NULL));

		}

	}

}



bool
@@ -236,6 +205,7 @@ _spdk_reactor_run(void *arg) 
{

	struct spdk_reactor	*reactor = arg;

	struct spdk_thread	*thread;

	uint64_t		last_rusage = 0;

	char			thread_name[32];



	snprintf(thread_name, sizeof(thread_name), "reactor_%u", reactor->lcore);
@@ -245,12 +215,6 @@ _spdk_reactor_run(void *arg) 
	}

	SPDK_NOTICELOG("Reactor started on core %u\n", reactor->lcore);



	if (g_context_switch_monitor_enabled) {

		spdk_set_thread(thread);

		_spdk_reactor_context_switch_monitor_start(reactor, NULL);

		spdk_set_thread(NULL);

	}



	while (1) {

		_spdk_event_queue_run_batch(reactor, thread);
@@ -259,11 +223,17 @@ _spdk_reactor_run(void *arg) 
		if (g_reactor_state != SPDK_REACTOR_STATE_RUNNING) {

			break;

		}



		if (g_context_switch_monitor_enabled) {

			uint64_t now = spdk_get_ticks();



			if ((last_rusage + CONTEXT_SWITCH_MONITOR_PERIOD) < now) {

				get_rusage(reactor);

				last_rusage = now;

			}

		}

	}



	spdk_set_thread(thread);

	_spdk_reactor_context_switch_monitor_stop(reactor, NULL);

	spdk_thread_exit(thread);

	return 0;

}