1 //===-- Timer.cpp ---------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 #include "lldb/Utility/Timer.h"
9 #include "lldb/Utility/Stream.h"
10 #include "llvm/Support/ManagedStatic.h"
11 #include "llvm/Support/Signposts.h"
12
13 #include <algorithm>
14 #include <map>
15 #include <mutex>
16 #include <utility>
17 #include <vector>
18
19 #include <cassert>
20 #include <cinttypes>
21 #include <cstdarg>
22 #include <cstdio>
23
24 using namespace lldb_private;
25
26 #define TIMER_INDENT_AMOUNT 2
27
28 namespace {
29 typedef std::vector<Timer *> TimerStack;
30 static std::atomic<Timer::Category *> g_categories;
31 } // end of anonymous namespace
32
33 /// Allows llvm::Timer to emit signposts when supported.
34 static llvm::ManagedStatic<llvm::SignpostEmitter> Signposts;
35
36 std::atomic<bool> Timer::g_quiet(true);
37 std::atomic<unsigned> Timer::g_display_depth(0);
GetFileMutex()38 static std::mutex &GetFileMutex() {
39 static std::mutex *g_file_mutex_ptr = new std::mutex();
40 return *g_file_mutex_ptr;
41 }
42
GetTimerStackForCurrentThread()43 static TimerStack &GetTimerStackForCurrentThread() {
44 static thread_local TimerStack g_stack;
45 return g_stack;
46 }
47
Category(const char * cat)48 Timer::Category::Category(const char *cat) : m_name(cat) {
49 m_nanos.store(0, std::memory_order_release);
50 m_nanos_total.store(0, std::memory_order_release);
51 m_count.store(0, std::memory_order_release);
52 Category *expected = g_categories;
53 do {
54 m_next = expected;
55 } while (!g_categories.compare_exchange_weak(expected, this));
56 }
57
SetQuiet(bool value)58 void Timer::SetQuiet(bool value) { g_quiet = value; }
59
Timer(Timer::Category & category,const char * format,...)60 Timer::Timer(Timer::Category &category, const char *format, ...)
61 : m_category(category), m_total_start(std::chrono::steady_clock::now()) {
62 Signposts->startInterval(this, m_category.GetName());
63 TimerStack &stack = GetTimerStackForCurrentThread();
64
65 stack.push_back(this);
66 if (!g_quiet && stack.size() <= g_display_depth) {
67 std::lock_guard<std::mutex> lock(GetFileMutex());
68
69 // Indent
70 ::fprintf(stdout, "%*s", int(stack.size() - 1) * TIMER_INDENT_AMOUNT, "");
71 // Print formatted string
72 va_list args;
73 va_start(args, format);
74 ::vfprintf(stdout, format, args);
75 va_end(args);
76
77 // Newline
78 ::fprintf(stdout, "\n");
79 }
80 }
81
~Timer()82 Timer::~Timer() {
83 using namespace std::chrono;
84
85 auto stop_time = steady_clock::now();
86 auto total_dur = stop_time - m_total_start;
87 auto timer_dur = total_dur - m_child_duration;
88
89 Signposts->endInterval(this, m_category.GetName());
90
91 TimerStack &stack = GetTimerStackForCurrentThread();
92 if (!g_quiet && stack.size() <= g_display_depth) {
93 std::lock_guard<std::mutex> lock(GetFileMutex());
94 ::fprintf(stdout, "%*s%.9f sec (%.9f sec)\n",
95 int(stack.size() - 1) * TIMER_INDENT_AMOUNT, "",
96 duration<double>(total_dur).count(),
97 duration<double>(timer_dur).count());
98 }
99
100 assert(stack.back() == this);
101 stack.pop_back();
102 if (!stack.empty())
103 stack.back()->ChildDuration(total_dur);
104
105 // Keep total results for each category so we can dump results.
106 m_category.m_nanos += std::chrono::nanoseconds(timer_dur).count();
107 m_category.m_nanos_total += std::chrono::nanoseconds(total_dur).count();
108 m_category.m_count++;
109 }
110
SetDisplayDepth(uint32_t depth)111 void Timer::SetDisplayDepth(uint32_t depth) { g_display_depth = depth; }
112
113 /* binary function predicate:
114 * - returns whether a person is less than another person
115 */
116 namespace {
117 struct Stats {
118 const char *name;
119 uint64_t nanos;
120 uint64_t nanos_total;
121 uint64_t count;
122 };
123 } // namespace
124
CategoryMapIteratorSortCriterion(const Stats & lhs,const Stats & rhs)125 static bool CategoryMapIteratorSortCriterion(const Stats &lhs,
126 const Stats &rhs) {
127 return lhs.nanos > rhs.nanos;
128 }
129
ResetCategoryTimes()130 void Timer::ResetCategoryTimes() {
131 for (Category *i = g_categories; i; i = i->m_next) {
132 i->m_nanos.store(0, std::memory_order_release);
133 i->m_nanos_total.store(0, std::memory_order_release);
134 i->m_count.store(0, std::memory_order_release);
135 }
136 }
137
DumpCategoryTimes(Stream & s)138 void Timer::DumpCategoryTimes(Stream &s) {
139 std::vector<Stats> sorted;
140 for (Category *i = g_categories; i; i = i->m_next) {
141 uint64_t nanos = i->m_nanos.load(std::memory_order_acquire);
142 if (nanos) {
143 uint64_t nanos_total = i->m_nanos_total.load(std::memory_order_acquire);
144 uint64_t count = i->m_count.load(std::memory_order_acquire);
145 Stats stats{i->m_name, nanos, nanos_total, count};
146 sorted.push_back(stats);
147 }
148 }
149 if (sorted.empty())
150 return; // Later code will break without any elements.
151
152 // Sort by time
153 llvm::sort(sorted, CategoryMapIteratorSortCriterion);
154
155 for (const auto &stats : sorted)
156 s.Printf("%.9f sec (total: %.3fs; child: %.3fs; count: %" PRIu64
157 ") for %s\n",
158 stats.nanos / 1000000000., stats.nanos_total / 1000000000.,
159 (stats.nanos_total - stats.nanos) / 1000000000., stats.count,
160 stats.name);
161 }
162