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event: Modify reactor to avoid calling spdk_get_ticks()

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Minimize the number of times spdk_get_ticks() is called
because it is expensive.

Change-Id: I2f34ca724ec28f42866b76d224dacbe1f31e7a41
Signed-off-by: Ben Walker <benjamin.walker@intel.com>
This commit is contained in:
Ben Walker 2017-01-20 10:23:30 -07:00 committed by Daniel Verkamp
parent 91d7d20c4e
commit 885a86a569
1 changed files with 17 additions and 7 deletions
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24
lib/event/reactor.c
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@ -298,7 +298,7 @@ _spdk_reactor_run(void *arg)
struct spdk_reactor *reactor = arg; struct spdk_reactor *reactor = arg;
struct spdk_poller *poller; struct spdk_poller *poller;
uint32_t event_count; uint32_t event_count;
uint64_t last_action, now; uint64_t idle_started, now;
uint64_t spin_cycles, sleep_cycles; uint64_t spin_cycles, sleep_cycles;
uint32_t sleep_us; uint32_t sleep_us;
@ -309,12 +309,14 @@ _spdk_reactor_run(void *arg)
spin_cycles = SPDK_REACTOR_SPIN_TIME_US * spdk_get_ticks_hz() / 1000000ULL; spin_cycles = SPDK_REACTOR_SPIN_TIME_US * spdk_get_ticks_hz() / 1000000ULL;
sleep_cycles = reactor->max_delay_us * spdk_get_ticks_hz() / 1000000ULL; sleep_cycles = reactor->max_delay_us * spdk_get_ticks_hz() / 1000000ULL;
last_action = spdk_get_ticks(); idle_started = 0;
while (1) { while (1) {
bool took_action = false;
event_count = spdk_event_queue_run_batch(rte_lcore_id()); event_count = spdk_event_queue_run_batch(rte_lcore_id());
if (event_count > 0) { if (event_count > 0) {
last_action = spdk_get_ticks(); took_action = true;
} }
poller = TAILQ_FIRST(&reactor->active_pollers); poller = TAILQ_FIRST(&reactor->active_pollers);
@ -328,7 +330,7 @@ _spdk_reactor_run(void *arg)
poller->state = SPDK_POLLER_STATE_WAITING; poller->state = SPDK_POLLER_STATE_WAITING;
TAILQ_INSERT_TAIL(&reactor->active_pollers, poller, tailq); TAILQ_INSERT_TAIL(&reactor->active_pollers, poller, tailq);
} }
last_action = spdk_get_ticks(); took_action = true;
} }
poller = TAILQ_FIRST(&reactor->timer_pollers); poller = TAILQ_FIRST(&reactor->timer_pollers);
@ -345,14 +347,22 @@ _spdk_reactor_run(void *arg)
poller->state = SPDK_POLLER_STATE_WAITING; poller->state = SPDK_POLLER_STATE_WAITING;
spdk_poller_insert_timer(reactor, poller, now); spdk_poller_insert_timer(reactor, poller, now);
} }
last_action = spdk_get_ticks(); took_action = true;
} }
} }
if (took_action) {
/* We were busy this loop iteration. Reset the idle timer. */
idle_started = 0;
} else if (idle_started == 0) {
/* We were previously busy, but this loop we took no actions. */
idle_started = spdk_get_ticks();
}
/* Determine if the thread can sleep */ /* Determine if the thread can sleep */
if (sleep_cycles > 0) { if (sleep_cycles && idle_started) {
now = spdk_get_ticks(); now = spdk_get_ticks();
if (now >= (last_action + spin_cycles)) { if (now >= (idle_started + spin_cycles)) {
sleep_us = reactor->max_delay_us; sleep_us = reactor->max_delay_us;
poller = TAILQ_FIRST(&reactor->timer_pollers); poller = TAILQ_FIRST(&reactor->timer_pollers);