Coverage Report

Created: 2025-03-13 18:54

/root/doris/be/src/util/spinlock.h
Line
Count
Source
1
// Licensed to the Apache Software Foundation (ASF) under one
2
// or more contributor license agreements.  See the NOTICE file
3
// distributed with this work for additional information
4
// regarding copyright ownership.  The ASF licenses this file
5
// to you under the Apache License, Version 2.0 (the
6
// "License"); you may not use this file except in compliance
7
// with the License.  You may obtain a copy of the License at
8
//
9
//   http://www.apache.org/licenses/LICENSE-2.0
10
//
11
// Unless required by applicable law or agreed to in writing,
12
// software distributed under the License is distributed on an
13
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14
// KIND, either express or implied.  See the License for the
15
// specific language governing permissions and limitations
16
// under the License.
17
// This file is copied from
18
// https://github.com/apache/impala/blob/branch-2.9.0/be/src/util/spinlock.h
19
// and modified by Doris
20
21
#pragma once
22
23
#include <sched.h> /* For sched_yield() */
24
25
#include <atomic>
26
27
namespace doris {
28
29
// Lightweight spinlock.
30
class SpinLock {
31
public:
32
44.0k
    SpinLock() : _locked(false) {
33
        // do nothing
34
44.0k
    }
35
36
    // Acquires the lock, spins until the lock becomes available
37
116k
    void lock() {
38
4.42M
        for (int spin_count = 0; !try_lock(); ++spin_count) {
39
4.30M
            if (spin_count < NUM_SPIN_CYCLES) {
40
3.56M
#if (defined(__i386) || defined(__x86_64__))
41
3.56M
                asm volatile("pause\n" : : : "memory");
42
#elif defined(__aarch64__)
43
                asm volatile("yield\n" ::: "memory");
44
#endif
45
3.56M
            } else {
46
738k
                sched_yield();
47
738k
                spin_count = 0;
48
738k
            }
49
4.30M
        }
50
116k
    }
51
52
116k
    void unlock() { _locked.clear(std::memory_order_release); }
53
54
    // Tries to acquire the lock
55
3.23M
    bool try_lock() { return !_locked.test_and_set(std::memory_order_acquire); }
56
57
private:
58
    static const int NUM_SPIN_CYCLES = 70;
59
    std::atomic_flag _locked;
60
};
61
62
} // end namespace doris