I'd like my program to read the cache line size of the CPU it's running on in C++.
I know that this can't be done portably, so I will need a solution for Linux and another for Windows (Solutions for other systems could be usefull to others, so post them if you know them).
For Linux I could read the content of /proc/cpuinfo and parse the line begining with cache_alignment. Maybe there is a better way involving a call to an API.
For Windows I simply have no idea.
在 Win32 上, GetLogicalProcessorInformation
将返回一个SYSTEM_LOGICAL_PROCESSOR_INFORMATION
,其中包含一个CACHE_DESCRIPTOR
,其中包含您需要的信息。
在 Linux 上尝试使用proccpuinfo 库,这是一个独立于体系结构的 C API,用于读取 /proc/cpuinfo
Looks like at least SCO unix ( http://uw714doc.sco.com/en/man/html.3C/sysconf.3C.html ) has _SC_CACHE_LINE for sysconf. Perhaps other platforms have something similar?
On Windows
#include <Windows.h>
#include <iostream>
using std::cout; using std::endl;
int main()
{
SYSTEM_INFO systemInfo;
GetSystemInfo(&systemInfo);
cout << "Page Size Is: " << systemInfo.dwPageSize;
getchar();
}
On Linux
Here is sample code for those who wonder how to to utilize the function in accepted answer:
#include <new>
#include <iostream>
#include <Windows.h>
void ShowCacheSize()
{
using CPUInfo = SYSTEM_LOGICAL_PROCESSOR_INFORMATION;
DWORD len = 0;
CPUInfo* buffer = nullptr;
// Determine required length of a buffer
if ((GetLogicalProcessorInformation(buffer, &len) == FALSE) && (GetLastError() == ERROR_INSUFFICIENT_BUFFER))
{
// Allocate buffer of required size
buffer = new (std::nothrow) CPUInfo[len]{ };
if (buffer == nullptr)
{
std::cout << "Buffer allocation of " << len << " bytes failed" << std::endl;
}
else if (GetLogicalProcessorInformation(buffer, &len) != FALSE)
{
for (DWORD i = 0; i < len; ++i)
{
// This will be true for multiple returned caches, we need just one
if (buffer[i].Relationship == RelationCache)
{
std::cout << "Cache line size is: " << buffer[i].Cache.LineSize << " bytes" << std::endl;
break;
}
}
}
else
{
std::cout << "ERROR: " << GetLastError() << std::endl;
}
delete[] buffer;
}
}
我认为您需要来自ntdll.dll
NtQuerySystemInformation
。
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