#ifndef GET_CACHE_LINE_SIZE_H_INCLUDED #define GET_CACHE_LINE_SIZE_H_INCLUDED // Author: Nick Strupat // Date: October 29, 2010 // Returns the cache line size (in bytes) of the processor, or 0 on failure #include <stddef.h> size_t cache_line_size(); #if defined(__APPLE__) #include <sys/sysctl.h> size_t cache_line_size() { size_t line_size = 0; size_t sizeof_line_size = sizeof(line_size); sysctlbyname("hw.cachelinesize", &line_size, &sizeof_line_size, 0, 0); return line_size; } #elif defined(_WIN32) #include <stdlib.h> #include <windows.h> size_t cache_line_size() { size_t line_size = 0; DWORD buffer_size = 0; DWORD i = 0; SYSTEM_LOGICAL_PROCESSOR_INFORMATION * buffer = 0; GetLogicalProcessorInformation(0, &buffer_size); buffer = (SYSTEM_LOGICAL_PROCESSOR_INFORMATION *)malloc(buffer_size); GetLogicalProcessorInformation(&buffer[0], &buffer_size); for (i = 0; i != buffer_size / sizeof(SYSTEM_LOGICAL_PROCESSOR_INFORMATION); ++i) { if (buffer[i].Relationship == RelationCache && buffer[i].Cache.Level == 1) { line_size = buffer[i].Cache.LineSize; break; } } free(buffer); return line_size; } #elif defined(linux) #include <stdio.h> size_t cache_line_size() { FILE * p = 0; p = fopen("/sys/devices/system/cpu/cpu0/cache/index0/coherency_line_size", "r"); unsigned int i = 0; if (p) { fscanf(p, "%d", &i); fclose(p); } return i; } #else #error Unrecognized platform #endif #endif
Monday 17 December 2012
Cross-platform function to get your cache line size
I wrote this function for a cache line aligned memory allocator which is for eventual use in my thread pool. It returns the line size (in bytes) of the host machine’s CPU cache, or 0 on failure. You can download it here. The source is below. Feel free to do whatever you want with it.
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