blob: 0e98d491d754c9a808e6390fed1f952d1ebaad21 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
|
// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#pragma once
#include <vespa/vespalib/util/time.h>
#include <vespa/vespalib/util/thread.h>
#include <atomic>
#include <condition_variable>
#include <mutex>
#include <vector>
namespace storage::distributor {
class DistributorStripeThread;
class TickableStripe;
/**
* Management and coordination of a pool of distributor stripe threads.
*
* Aside from handling the threads themselves, the pool crucially offers a well-defined
* thread synchronization/coordination API meant for ensuring all stripe threads are in
* a well defined state before accessing them:
*
* - park_all_threads() returns once ALL threads are in a "parked" state where they
* may not race with any operations performed on them by the caller. In essence, this
* acts as if a (very large) mutex is held by the caller that prevents the stripe
* from doing anything of its own volition. Must be followed by:
* - unpark_all_threads() returns once ALL threads have been confirmed released from
* a previously parked state. Must be called after park_all_threads().
*
* Neither park_all_threads() or unpark_all_threads() may be called prior to calling start().
*
* It's possible to set stripe thread tick-specific options (wait duration, ticks before
* wait) both before and after start() is called. The options will be propagated to any
* running stripe threads in a thread-safe, lock-free manner.
*/
class DistributorStripePool {
using StripeVector = std::vector<std::unique_ptr<DistributorStripeThread>>;
uint8_t _n_stripe_bits;
StripeVector _stripes;
vespalib::ThreadPool _threads;
std::mutex _mutex;
std::condition_variable _parker_cond;
size_t _parked_threads; // Must be protected by _park_mutex
vespalib::duration _bootstrap_tick_wait_duration;
uint32_t _bootstrap_ticks_before_wait;
bool _single_threaded_test_mode;
bool _stopped;
friend class DistributorStripeThread;
struct PrivateCtorTag{};
public:
using const_iterator = StripeVector::const_iterator;
DistributorStripePool(bool test_mode, PrivateCtorTag);
DistributorStripePool();
~DistributorStripePool();
static std::unique_ptr<DistributorStripePool> make_non_threaded_pool_for_testing();
// Set up the stripe pool with a 1-1 relationship between the provided
// stripes and running threads. Can only be called once per pool.
//
// Precondition: stripes.size() > 0 &&
// when stripes.size() > 1: is a power of 2 and within storage::MaxStripes boundary
void start(const std::vector<TickableStripe*>& stripes);
void stop_and_join();
const_iterator begin() const noexcept { return _stripes.begin(); }
const_iterator end() const noexcept { return _stripes.end(); }
const_iterator cbegin() const noexcept { return _stripes.cbegin(); }
const_iterator cend() const noexcept { return _stripes.cend(); }
void park_all_threads() noexcept;
void unpark_all_threads() noexcept;
[[nodiscard]] const DistributorStripeThread& stripe_thread(size_t idx) const noexcept {
return *_stripes[idx];
}
[[nodiscard]] DistributorStripeThread& stripe_thread(size_t idx) noexcept {
return *_stripes[idx];
}
void notify_stripe_event_has_triggered(size_t stripe_idx) noexcept;
[[nodiscard]] const TickableStripe& stripe_of_key(uint64_t key) const noexcept;
[[nodiscard]] TickableStripe& stripe_of_key(uint64_t key) noexcept;
[[nodiscard]] size_t stripe_count() const noexcept { return _stripes.size(); }
[[nodiscard]] bool is_stopped() const noexcept { return _stopped; }
// Applies to all threads. May be called both before and after start(). Thread safe.
void set_tick_wait_duration(vespalib::duration new_tick_wait_duration) noexcept;
void set_ticks_before_wait(uint32_t new_ticks_before_wait) noexcept;
private:
void park_thread_until_released(DistributorStripeThread& thread) noexcept;
};
}
|
