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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#include "distributor_stripe_thread.h"
#include "distributor_stripe.h"
#include "distributor_stripe_pool.h"
#include "tickable_stripe.h"
#include <cassert>
namespace storage::distributor {
DistributorStripeThread::DistributorStripeThread(TickableStripe& stripe,
DistributorStripePool& stripe_pool)
: _stripe(stripe),
_stripe_pool(stripe_pool),
_tick_wait_duration(vespalib::adjustTimeoutByDetectedHz(1ms)),
_mutex(),
_event_cond(),
_park_cond(),
_ticks_before_wait(10),
_should_park(false),
_should_stop(false),
_waiting_for_event(false)
{}
DistributorStripeThread::~DistributorStripeThread() = default;
void DistributorStripeThread::run() {
uint32_t tick_waits_inhibited = 0;
while (!should_stop_thread_relaxed()) {
while (should_park_relaxed()) {
_stripe_pool.park_thread_until_released(*this);
}
// TODO consider enum to only trigger "ticks before wait"-behavior when maintenance was done
const bool did_work = _stripe.tick();
if (did_work) {
tick_waits_inhibited = 0;
} else if (tick_waits_inhibited >= ticks_before_wait_relaxed()) {
wait_until_event_notified_or_timed_out();
tick_waits_inhibited = 0;
} else {
++tick_waits_inhibited;
}
}
}
void DistributorStripeThread::signal_wants_park() noexcept {
std::lock_guard lock(_mutex);
assert(!should_park_relaxed());
_should_park.store(true, std::memory_order_relaxed);
if (_waiting_for_event) {
_event_cond.notify_one();
}
}
void DistributorStripeThread::unpark_thread() noexcept {
std::lock_guard lock(_mutex);
assert(should_park_relaxed());
_should_park.store(false, std::memory_order_relaxed);
_park_cond.notify_one();
}
void DistributorStripeThread::wait_until_event_notified_or_timed_out() noexcept {
std::unique_lock lock(_mutex);
if (should_stop_thread_relaxed() || should_park_relaxed()) {
return;
}
_waiting_for_event = true;
_event_cond.wait_for(lock, tick_wait_duration_relaxed());
_waiting_for_event = false;
}
void DistributorStripeThread::wait_until_unparked() noexcept {
std::unique_lock lock(_mutex);
// _should_park is always written within _mutex, relaxed load is safe.
_park_cond.wait(lock, [this]{ return !should_park_relaxed(); });
}
void DistributorStripeThread::notify_event_has_triggered() noexcept {
// TODO mutex protect and add flag for "should tick immediately next time"
// TODO only notify if _waiting_for_event == true
_event_cond.notify_one();
}
void DistributorStripeThread::signal_should_stop() noexcept {
std::unique_lock lock(_mutex);
assert(!should_park_relaxed());
_should_stop.store(true, std::memory_order_relaxed);
if (_waiting_for_event) {
_event_cond.notify_one();
}
// TODO if we ever need it, handle pending thread park. For now we assume that
// the caller never attempts to concurrently park and stop threads.
}
void DistributorStripeThread::set_tick_wait_duration(vespalib::duration new_tick_wait_duration) noexcept {
static_assert(AtomicDuration::is_always_lock_free);
// No memory ordering required for a "lazy" single value setting such as the tick duration
_tick_wait_duration.store(new_tick_wait_duration, std::memory_order_relaxed);
}
void DistributorStripeThread::set_ticks_before_wait(uint32_t new_ticks_before_wait) noexcept {
_ticks_before_wait.store(new_ticks_before_wait, std::memory_order_relaxed);
}
}
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