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add back /proc/cpuinfo as a fallback for some platforms (#1918)

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dominic 2025-02-05 12:21:47 +00:00 committed by GitHub
parent c35af58b61
commit 2e16afc3fd
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1 changed files with 50 additions and 1 deletions
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51
src/sysinfo.cc
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@ -508,6 +508,55 @@ int GetNumCPUsImpl() {
hardware_threads.max_hthreads = 1;
}
return hardware_threads.max_hthreads;
#else
// Fallback for platforms (such as WASM) that aren't covered above.
int num_cpus = 0;
int max_id = -1;
std::ifstream f("/proc/cpuinfo");
if (!f.is_open()) {
std::cerr << "Failed to open /proc/cpuinfo\n";
return -1;
}
#if defined(__alpha__)
const std::string Key = "cpus detected";
#else
const std::string Key = "processor";
#endif
std::string ln;
while (std::getline(f, ln)) {
if (ln.empty()) continue;
std::size_t split_idx = ln.find(':');
std::string value;
#if defined(__s390__)
// s390 has another format in /proc/cpuinfo
// it needs to be parsed differently
if (split_idx != std::string::npos)
value = ln.substr(Key.size() + 1, split_idx - Key.size() - 1);
#else
if (split_idx != std::string::npos) value = ln.substr(split_idx + 1);
#endif
if (ln.size() >= Key.size() && ln.compare(0, Key.size(), Key) == 0) {
num_cpus++;
if (!value.empty()) {
const int cur_id = benchmark::stoi(value);
max_id = std::max(cur_id, max_id);
}
}
}
if (f.bad()) {
PrintErrorAndDie("Failure reading /proc/cpuinfo");
}
if (!f.eof()) {
PrintErrorAndDie("Failed to read to end of /proc/cpuinfo");
}
f.close();
if ((max_id + 1) != num_cpus) {
fprintf(stderr,
"CPU ID assignments in /proc/cpuinfo seem messed up."
" This is usually caused by a bad BIOS.\n");
}
return num_cpus;
#endif
BENCHMARK_UNREACHABLE();
}
@ -516,7 +565,7 @@ int GetNumCPUs() {
int num_cpus = GetNumCPUsImpl();
if (num_cpus < 1) {
std::cerr << "Unable to extract number of CPUs.\n";
/* There is at least one CPU which we run on. */
// There must be at least one CPU on which we're running.
num_cpus = 1;
}
return num_cpus;