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1 | |
2 | /* | |
3 | * This file is open source software, licensed to you under the terms | |
4 | * of the Apache License, Version 2.0 (the "License"). See the NOTICE file | |
5 | * distributed with this work for additional information regarding copyright | |
6 | * ownership. You may not use this file except in compliance with the License. | |
7 | * | |
8 | * You may obtain a copy of the License at | |
9 | * | |
10 | * http://www.apache.org/licenses/LICENSE-2.0 | |
11 | * | |
12 | * Unless required by applicable law or agreed to in writing, | |
13 | * software distributed under the License is distributed on an | |
14 | * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY | |
15 | * KIND, either express or implied. See the License for the | |
16 | * specific language governing permissions and limitations | |
17 | * under the License. | |
18 | */ | |
19 | /* | |
20 | * Copyright (C) 2018 ScyllaDB | |
21 | */ | |
22 | ||
23 | #pragma once | |
24 | ||
25 | #include <signal.h> | |
26 | #include <limits> | |
27 | #include <chrono> | |
28 | #include <functional> | |
20effc67 | 29 | #include <memory> |
11fdf7f2 | 30 | #include <seastar/core/posix.hh> |
9f95a23c | 31 | #include <seastar/core/metrics_registration.hh> |
20effc67 TL |
32 | #include <seastar/core/scheduling.hh> |
33 | #include <linux/perf_event.h> | |
11fdf7f2 TL |
34 | |
35 | namespace seastar { | |
36 | ||
37 | class reactor; | |
f67539c2 | 38 | class thread_cputime_clock; |
11fdf7f2 TL |
39 | |
40 | namespace internal { | |
41 | ||
42 | struct cpu_stall_detector_config { | |
43 | std::chrono::duration<double> threshold = std::chrono::seconds(2); | |
44 | unsigned stall_detector_reports_per_minute = 1; | |
45 | float slack = 0.3; // fraction of threshold that we're allowed to overshoot | |
20effc67 | 46 | bool oneline = true; // print a simplified backtrace on a single line |
11fdf7f2 TL |
47 | std::function<void ()> report; // alternative reporting function for tests |
48 | }; | |
49 | ||
50 | // Detects stalls in continuations that run for too long | |
51 | class cpu_stall_detector { | |
20effc67 | 52 | protected: |
9f95a23c | 53 | std::atomic<uint64_t> _last_tasks_processed_seen{}; |
11fdf7f2 TL |
54 | unsigned _stall_detector_reports_per_minute; |
55 | std::atomic<uint64_t> _stall_detector_missed_ticks = { 0 }; | |
56 | unsigned _reported = 0; | |
9f95a23c | 57 | unsigned _total_reported = 0; |
11fdf7f2 TL |
58 | unsigned _max_reports_per_minute; |
59 | unsigned _shard_id; | |
60 | unsigned _thread_id; | |
61 | unsigned _report_at{}; | |
20effc67 TL |
62 | sched_clock::time_point _minute_mark{}; |
63 | sched_clock::time_point _rearm_timer_at{}; | |
64 | sched_clock::time_point _run_started_at{}; | |
65 | sched_clock::duration _threshold; | |
66 | sched_clock::duration _slack; | |
11fdf7f2 | 67 | cpu_stall_detector_config _config; |
9f95a23c | 68 | seastar::metrics::metric_groups _metrics; |
11fdf7f2 | 69 | friend reactor; |
20effc67 TL |
70 | virtual bool reap_event_and_check_spuriousness() { |
71 | return false; | |
72 | } | |
73 | virtual void maybe_report_kernel_trace() {} | |
11fdf7f2 TL |
74 | private: |
75 | void maybe_report(); | |
20effc67 TL |
76 | virtual void arm_timer() = 0; |
77 | void report_suppressions(sched_clock::time_point now); | |
11fdf7f2 | 78 | public: |
f67539c2 TL |
79 | using clock_type = thread_cputime_clock; |
80 | public: | |
81 | explicit cpu_stall_detector(cpu_stall_detector_config cfg = {}); | |
20effc67 | 82 | virtual ~cpu_stall_detector() = default; |
11fdf7f2 | 83 | static int signal_number() { return SIGRTMIN + 1; } |
20effc67 TL |
84 | void start_task_run(sched_clock::time_point now); |
85 | void end_task_run(sched_clock::time_point now); | |
11fdf7f2 TL |
86 | void generate_trace(); |
87 | void update_config(cpu_stall_detector_config cfg); | |
88 | cpu_stall_detector_config get_config() const; | |
89 | void on_signal(); | |
20effc67 | 90 | virtual void start_sleep() = 0; |
11fdf7f2 TL |
91 | void end_sleep(); |
92 | }; | |
93 | ||
20effc67 TL |
94 | class cpu_stall_detector_posix_timer : public cpu_stall_detector { |
95 | timer_t _timer; | |
96 | public: | |
97 | explicit cpu_stall_detector_posix_timer(cpu_stall_detector_config cfg = {}); | |
98 | virtual ~cpu_stall_detector_posix_timer() override; | |
99 | private: | |
100 | virtual void arm_timer() override; | |
101 | virtual void start_sleep() override; | |
102 | }; | |
103 | ||
104 | class cpu_stall_detector_linux_perf_event : public cpu_stall_detector { | |
105 | file_desc _fd; | |
106 | bool _enabled = false; | |
107 | uint64_t _current_period = 0; | |
108 | struct ::perf_event_mmap_page* _mmap; | |
109 | char* _data_area; | |
110 | size_t _data_area_mask; | |
111 | private: | |
112 | class data_area_reader { | |
113 | cpu_stall_detector_linux_perf_event& _p; | |
114 | const char* _data_area; | |
115 | size_t _data_area_mask; | |
116 | uint64_t _head; | |
117 | uint64_t _tail; | |
118 | public: | |
119 | explicit data_area_reader(cpu_stall_detector_linux_perf_event& p) | |
120 | : _p(p) | |
121 | , _data_area(p._data_area) | |
122 | , _data_area_mask(p._data_area_mask) { | |
123 | _head = _p._mmap->data_head; | |
124 | _tail = _p._mmap->data_tail; | |
125 | std::atomic_thread_fence(std::memory_order_acquire); // required after reading data_head | |
126 | } | |
127 | ~data_area_reader() { | |
128 | std::atomic_thread_fence(std::memory_order_release); // not documented, but probably required before writing data_tail | |
129 | _p._mmap->data_tail = _tail; | |
130 | } | |
131 | uint64_t read_u64() { | |
132 | uint64_t ret; | |
133 | // We cannot wrap around if the 8-byte unit is aligned | |
134 | std::copy_n(_data_area + (_tail & _data_area_mask), 8, reinterpret_cast<char*>(&ret)); | |
135 | _tail += 8; | |
136 | return ret; | |
137 | } | |
138 | template <typename S> | |
139 | S read_struct() { | |
140 | static_assert(sizeof(S) % 8 == 0); | |
141 | S ret; | |
142 | char* p = reinterpret_cast<char*>(&ret); | |
143 | for (size_t i = 0; i != sizeof(S); i += 8) { | |
144 | uint64_t w = read_u64(); | |
145 | std::copy_n(reinterpret_cast<const char*>(&w), 8, p + i); | |
146 | } | |
147 | return ret; | |
148 | } | |
149 | void skip(uint64_t bytes_to_skip) { | |
150 | _tail += bytes_to_skip; | |
151 | } | |
152 | bool have_data() const { | |
153 | return _head != _tail; | |
154 | } | |
155 | }; | |
156 | public: | |
157 | static std::unique_ptr<cpu_stall_detector_linux_perf_event> try_make(cpu_stall_detector_config cfg = {}); | |
158 | explicit cpu_stall_detector_linux_perf_event(file_desc fd, cpu_stall_detector_config cfg = {}); | |
159 | ~cpu_stall_detector_linux_perf_event(); | |
160 | virtual void arm_timer() override; | |
161 | virtual void start_sleep() override; | |
162 | virtual bool reap_event_and_check_spuriousness() override; | |
163 | virtual void maybe_report_kernel_trace() override; | |
164 | }; | |
165 | ||
166 | std::unique_ptr<cpu_stall_detector> make_cpu_stall_detector(cpu_stall_detector_config cfg = {}); | |
167 | ||
11fdf7f2 TL |
168 | } |
169 | } |