1 /*
2 * Copyright (C) 2023 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 <time.h>
18 #include <cstring>
19 #include <iostream>
20 #include <optional>
21 #include <sstream>
22 #include <unordered_map>
23
s2ns(uint64_t s)24 uint64_t s2ns(uint64_t s) {
25 return s * 1000000000ull;
26 }
27
PrintHelpAndExit(const std::string & error_msg="")28 void PrintHelpAndExit(const std::string& error_msg = "") {
29 int exit_error = 0;
30 if (!error_msg.empty()) {
31 std::cout << error_msg << "\n";
32 exit_error = 1;
33 }
34
35 std::cout << "Usage: ClockTime [CLOCK_ID]\n"
36 << "CLOCK_ID can be CLOCK_REALTIME or CLOCK_MONOTONIC \n"
37 << "if omitted, it will obtain the processors's time-stamp counter \n"
38 << "on x86 it will use RDTSC, on arm64 it will use MRS CNTCVT. \n"
39 << "-h, --help Print this help message\n";
40
41 exit(exit_error);
42 }
43
GetTime(int type,uint64_t * ts_ns)44 int GetTime(int type, uint64_t* ts_ns) {
45 struct timespec ts;
46 int res = clock_gettime(type, &ts);
47 if (!res) {
48 *ts_ns = s2ns(ts.tv_sec) + ts.tv_nsec;
49 }
50 return res;
51 }
52
GetCPUTicks()53 uint64_t GetCPUTicks() {
54 #if defined(__x86_64__) || defined(__amd64__)
55 uint32_t hi, lo;
56 asm volatile("rdtsc" : "=a"(lo), "=d"(hi));
57 return ((uint64_t)lo) | (((uint64_t)hi) << 32);
58 #elif defined(__aarch64__)
59 uint64_t vct;
60 asm volatile("mrs %0, cntvct_el0" : "=r"(vct));
61 return vct;
62 #else
63 PrintHelpAndExit("GetCPUTicks() is not supported");
64 return 0;
65 #endif
66 }
67
main(int argc,char * argv[])68 int main(int argc, char* argv[]) {
69 std::unordered_map<std::string, clockid_t> clock_map = {
70 std::make_pair("CLOCK_REALTIME", CLOCK_REALTIME),
71 std::make_pair("CLOCK_MONOTONIC", CLOCK_MONOTONIC)};
72
73 if (argc == 1) {
74 std::cout << GetCPUTicks() << "\n";
75 } else if (argc == 2) {
76 if (!(strcmp(argv[1], "-h") && strcmp(argv[1], "--help"))) {
77 PrintHelpAndExit();
78 }
79
80 uint64_t ts_ns;
81 auto it = clock_map.find(argv[1]);
82 if (it == clock_map.end()) {
83 PrintHelpAndExit("Wrong CLOCK_ID");
84 }
85
86 int res = GetTime(it->second, &ts_ns);
87 if (res) {
88 std::stringstream err_msg("GetTime() got error");
89 err_msg << res;
90 PrintHelpAndExit(err_msg.str());
91 }
92
93 std::cout << ts_ns << "\n";
94 } else {
95 PrintHelpAndExit("Wrong number of arguments");
96 }
97
98 return EXIT_SUCCESS;
99 }
100