1 /*
2 * Copyright (C) 2019 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <memory>
18
19 #include <errno.h>
20 #include <fcntl.h>
21 #include <inttypes.h>
22 #include <signal.h>
23 #include <stdio.h>
24 #include <stdlib.h>
25 #include <string.h>
26 #include <sys/stat.h>
27 #include <sys/types.h>
28 #include <unistd.h>
29
30 namespace {
31
32 constexpr auto kIdleSize = 10000 * 4096;
33 constexpr auto kNoIdleSize = 1000 * 4096;
34
35 static bool interrupted = false;
36
37 volatile unsigned char* __attribute__((noinline)) AllocIdle(size_t bytes);
AllocIdle(size_t bytes)38 volatile unsigned char* __attribute__((noinline)) AllocIdle(size_t bytes) {
39 // This volatile is needed to prevent the compiler from trying to be
40 // helpful and compiling a "useless" malloc + free into a noop.
41 volatile unsigned char* x = static_cast<unsigned char*>(malloc(bytes));
42 if (x) {
43 x[1] = 'x';
44 }
45 return x;
46 }
47
48 volatile unsigned char* __attribute__((noinline)) AllocNoIdle(size_t bytes);
AllocNoIdle(size_t bytes)49 volatile unsigned char* __attribute__((noinline)) AllocNoIdle(size_t bytes) {
50 // This volatile is needed to prevent the compiler from trying to be
51 // helpful and compiling a "useless" malloc + free into a noop.
52 volatile unsigned char* x = static_cast<unsigned char*>(malloc(bytes));
53 if (x) {
54 x[0] = 'x';
55 }
56 return x;
57 }
58
59 class MemoryToucher {
60 public:
61 virtual void Touch(volatile unsigned char* nonidle) = 0;
62 virtual ~MemoryToucher() = default;
63 };
64
65 class ReadDevZeroChunks : public MemoryToucher {
66 public:
ReadDevZeroChunks(size_t chunk_size)67 ReadDevZeroChunks(size_t chunk_size)
68 : chunk_size_(chunk_size), fd_(open("/dev/zero", O_RDONLY)) {
69 if (fd_ == -1) {
70 fprintf(stderr, "Failed to open: %s", strerror(errno));
71 abort();
72 }
73 }
74
75 ~ReadDevZeroChunks() override = default;
76
Touch(volatile unsigned char * nonidle)77 void Touch(volatile unsigned char* nonidle) override {
78 size_t total_rd = 0;
79 while (total_rd < kNoIdleSize) {
80 size_t chunk = chunk_size_;
81 if (chunk > kNoIdleSize - total_rd)
82 chunk = kNoIdleSize - total_rd;
83
84 ssize_t rd =
85 read(fd_, const_cast<unsigned char*>(nonidle) + total_rd, chunk);
86 if (rd == -1) {
87 fprintf(stderr, "Failed to write: %s.", strerror(errno));
88 abort();
89 }
90 total_rd += static_cast<size_t>(rd);
91 }
92 }
93
94 private:
95 size_t chunk_size_;
96 int fd_;
97 };
98
99 class ReadDevZeroChunksAndSleep : public ReadDevZeroChunks {
100 public:
ReadDevZeroChunksAndSleep(size_t chunk_size)101 ReadDevZeroChunksAndSleep(size_t chunk_size)
102 : ReadDevZeroChunks(chunk_size) {}
Touch(volatile unsigned char * nonidle)103 void Touch(volatile unsigned char* nonidle) override {
104 ReadDevZeroChunks::Touch(nonidle);
105 sleep(1);
106 }
107 };
108
109 class SumUp : public MemoryToucher {
110 public:
SumUp()111 SumUp()
112 : sum_(const_cast<volatile uint64_t*>(
113 static_cast<uint64_t*>(malloc(sizeof(uint64_t))))) {}
114 ~SumUp() override = default;
115
Touch(volatile unsigned char * nonidle)116 void Touch(volatile unsigned char* nonidle) override {
117 for (size_t i = 0; i < kNoIdleSize; ++i)
118 *sum_ += nonidle[i];
119 }
120
121 private:
122 volatile uint64_t* sum_;
123 };
124
125 class ReadDevZeroChunksAndSum : public ReadDevZeroChunks {
126 public:
ReadDevZeroChunksAndSum(size_t chunk_size)127 ReadDevZeroChunksAndSum(size_t chunk_size) : ReadDevZeroChunks(chunk_size) {}
Touch(volatile unsigned char * nonidle)128 void Touch(volatile unsigned char* nonidle) override {
129 ReadDevZeroChunks::Touch(nonidle);
130 sum_up_.Touch(nonidle);
131 }
132
133 private:
134 SumUp sum_up_;
135 };
136
137 class AssignValues : public MemoryToucher {
138 public:
139 ~AssignValues() override = default;
140
Touch(volatile unsigned char * nonidle)141 void Touch(volatile unsigned char* nonidle) override {
142 for (size_t i = 0; i < kNoIdleSize; ++i)
143 nonidle[i] = static_cast<unsigned char>(i % 256);
144 }
145 };
146
147 } // namespace
148
main(int argc,char ** argv)149 int main(int argc, char** argv) {
150 volatile auto* idle = AllocIdle(kIdleSize);
151 volatile auto* nonidle = AllocNoIdle(kNoIdleSize);
152
153 printf("Own PID: %" PRIdMAX "\n", static_cast<intmax_t>(getpid()));
154 printf("Idle: %p\n", static_cast<void*>(const_cast<unsigned char*>(idle)));
155 printf("Nonidle: %p\n",
156 static_cast<void*>(const_cast<unsigned char*>(nonidle)));
157
158 for (size_t i = 0; i < kIdleSize; ++i)
159 idle[i] = static_cast<unsigned char>(i % 256);
160 for (size_t i = 0; i < kNoIdleSize; ++i)
161 nonidle[i] = static_cast<unsigned char>(i % 256);
162
163 printf("Allocated everything.\n");
164
165 struct sigaction action = {};
166 action.sa_handler = [](int) { interrupted = true; };
167 if (sigaction(SIGUSR1, &action, nullptr) != 0) {
168 fprintf(stderr, "Failed to register signal handler.\n");
169 abort();
170 }
171
172 if (argc < 2) {
173 fprintf(stderr,
174 "Specifiy one of AssignValues / SumUp / ReadDevZeroChunks\n");
175 abort();
176 }
177
178 std::unique_ptr<MemoryToucher> toucher;
179 if (strcmp(argv[1], "AssignValues") == 0) {
180 toucher.reset(new AssignValues());
181 printf("Using AssignValues.\n");
182 } else if (strcmp(argv[1], "SumUp") == 0) {
183 toucher.reset(new SumUp());
184 printf("Using SumUp.\n");
185 } else if (strcmp(argv[1], "ReadDevZeroChunks") == 0 ||
186 strcmp(argv[1], "ReadDevZeroChunksAndSleep") == 0 ||
187 strcmp(argv[1], "ReadDevZeroChunksAndSum") == 0) {
188 if (argc < 3) {
189 fprintf(stderr, "Specify chunk size.\n");
190 abort();
191 }
192 char* end;
193 long long chunk_arg = strtoll(argv[2], &end, 10);
194 if (*end != '\0' || *argv[2] == '\0') {
195 fprintf(stderr, "Invalid chunk size: %s\n", argv[2]);
196 abort();
197 }
198 if (strcmp(argv[1], "ReadDevZeroChunksAndSleep") == 0) {
199 printf("Using ReadDevZeroChunksAndSleep.\n");
200 toucher.reset(
201 new ReadDevZeroChunksAndSleep(static_cast<size_t>(chunk_arg)));
202 } else if (strcmp(argv[1], "ReadDevZeroChunksAndSum") == 0) {
203 printf("Using ReadDevZeroChunksAndSum.\n");
204 toucher.reset(
205 new ReadDevZeroChunksAndSum(static_cast<size_t>(chunk_arg)));
206 } else {
207 printf("Using ReadDevZeroChunks.\n");
208 toucher.reset(new ReadDevZeroChunks(static_cast<size_t>(chunk_arg)));
209 }
210 } else {
211 fprintf(stderr, "Invalid input.\n");
212 abort();
213 }
214
215 while (true) {
216 bool report = interrupted;
217 if (report) {
218 printf("Waiting to finish touching everything.\n");
219 interrupted = false;
220 sleep(2);
221 }
222
223 toucher->Touch(nonidle);
224
225 if (report)
226 printf("Touched everything.\n");
227 }
228 }
229