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Fixed processor count detection on Windows #1674

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Merged
jhasse merged 6 commits into from
Jan 1, 2021
Merged

Fixed processor count detection on Windows #1674

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de64856
Fixed processor count detection on Windows when multiple processor gr…
Nov 12, 2019
48a8a7a
Use symbolic constant as suggested in code review
cameron314 Nov 13, 2019
9d502da
Removed unnecessary #ifdef following code review
Nov 13, 2019
546e27c
Style changes following code review
Nov 20, 2019
9e1e51a
Tweaks following code review
cameron314 Jun 10, 2020
4b07ca3
Added preprocessor if to clarify processor count workaround code is o…
cameron314 Dec 31, 2020
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29 changes: 29 additions & 0 deletions src/util.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -481,6 +481,35 @@ string StripAnsiEscapeCodes(const string& in) {

int GetProcessorCount() {
#ifdef _WIN32
#ifndef _WIN64
// Need to use GetLogicalProcessorInformationEx to get real core count on
// machines with >64 cores. See https://stackoverflow.com/a/31209344/21475
DWORD len = 0;
if (!GetLogicalProcessorInformationEx(RelationProcessorCore, nullptr, &len)
&& GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
std::vector<char> buf(len);
int cores = 0;
if (GetLogicalProcessorInformationEx(RelationProcessorCore,
reinterpret_cast<PSYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX>(
buf.data()), &len)) {
for (DWORD i = 0; i < len; ) {
auto info = reinterpret_cast<PSYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX>(
buf.data() + i);
if (info->Relationship == RelationProcessorCore &&
info->Processor.GroupCount == 1) {
for (KAFFINITY core_mask = info->Processor.GroupMask[0].Mask;
core_mask; core_mask >>= 1) {
cores += (core_mask & 1);
}
}
i += info->Size;
}
if (cores != 0) {
return cores;
}
}
}
#endif
return GetActiveProcessorCount(ALL_PROCESSOR_GROUPS);
#else
#ifdef CPU_COUNT
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