diff options
| -rw-r--r-- | src/ioq.c | 18 |
1 files changed, 17 insertions, 1 deletions
@@ -277,10 +277,26 @@ static struct ioq_monitor *ioq_slot_monitor(struct ioqq *ioqq, ioq_slot *slot) { /** Atomically wait for a slot to change. */ _noinline static uintptr_t ioq_slot_wait(struct ioqq *ioqq, ioq_slot *slot, uintptr_t value) { + // Try spinning a few times before blocking + uintptr_t ret; + for (int i = 0; i < 10; ++i) { + // Exponential backoff + for (int j = 0; j < (1 << i); ++j) { + spin_loop(); + } + + // Check if the slot changed + ret = load(slot, relaxed); + if (ret != value) { + return ret; + } + } + + // Nothing changed, start blocking struct ioq_monitor *monitor = ioq_slot_monitor(ioqq, slot); mutex_lock(&monitor->mutex); - uintptr_t ret = load(slot, relaxed); + ret = load(slot, relaxed); if (ret != value) { goto done; } |