mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-25 00:52:02 +00:00
100 lines
3.6 KiB
C++
100 lines
3.6 KiB
C++
/************************* dispatch_example.cpp ****************************
|
|
| Author: Agner Fog
|
|
| Date created: 2012-05-30
|
|
| Last modified: 2014-07-23
|
|
| Version: 1.14
|
|
| Project: vector classes
|
|
| Description:
|
|
| Example of CPU dispatching.
|
|
|
|
|
| # Example of compiling this with GCC compiler:
|
|
| # Compile dispatch_example.cpp five times for different instruction sets:
|
|
| g++ -O3 -msse2 -c dispatch_example.cpp -od2.o
|
|
| g++ -O3 -msse4.1 -c dispatch_example.cpp -od5.o
|
|
| g++ -O3 -mavx -c dispatch_example.cpp -od7.o
|
|
| g++ -O3 -mavx2 -c dispatch_example.cpp -od8.o
|
|
| g++ -O3 -mavx512f -c dispatch_example.cpp -od9.o
|
|
| g++ -O3 -msse2 -otest instrset_detect.cpp d2.o d5.o d7.o d8.o d9.o
|
|
| ./test
|
|
|
|
|
| (c) Copyright 2012 - 2014 GNU General Public License http://www.gnu.org/licenses
|
|
\*****************************************************************************/
|
|
|
|
#include <stdio.h>
|
|
|
|
#define MAX_VECTOR_SIZE 512
|
|
#include "vectorclass.h"
|
|
|
|
|
|
// define function type (change this to fit your purpose. Should not contain vector types)
|
|
typedef float MyFuncType(float*);
|
|
|
|
// function prototypes for each version
|
|
MyFuncType myfunc, myfunc_SSE2, myfunc_SSE41, myfunc_AVX, myfunc_AVX2, myfunc_AVX512, myfunc_dispatch;
|
|
|
|
// Define function name depending on which instruction set we compile for
|
|
#if INSTRSET == 2 // SSE2
|
|
#define FUNCNAME myfunc_SSE2
|
|
#elif INSTRSET == 5 // SSE4.1
|
|
#define FUNCNAME myfunc_SSE41
|
|
#elif INSTRSET == 7 // AVX
|
|
#define FUNCNAME myfunc_AVX
|
|
#elif INSTRSET == 8 // AVX2
|
|
#define FUNCNAME myfunc_AVX2
|
|
#elif INSTRSET == 9 // AVX512
|
|
#define FUNCNAME myfunc_AVX512
|
|
#endif
|
|
|
|
// specific version of the function. Compile once for each version
|
|
float FUNCNAME (float * f) {
|
|
Vec16f a; // vector of 16 floats
|
|
a.load(f); // load array into vector
|
|
return horizontal_add(a); // return sum of 16 elements
|
|
}
|
|
|
|
|
|
#if INSTRSET == 2
|
|
// make dispatcher in only the lowest of the compiled versions
|
|
|
|
// Function pointer initially points to the dispatcher.
|
|
// After first call it points to the selected version
|
|
MyFuncType * myfunc_pointer = &myfunc_dispatch; // function pointer
|
|
|
|
// Dispatcher
|
|
float myfunc_dispatch(float * f) {
|
|
int iset = instrset_detect(); // Detect supported instruction set
|
|
if (iset >= 9) myfunc_pointer = &myfunc_AVX512; // AVX512 version
|
|
else if (iset >= 8) myfunc_pointer = &myfunc_AVX2; // AVX2 version
|
|
else if (iset >= 7) myfunc_pointer = &myfunc_AVX; // AVX version
|
|
else if (iset >= 5) myfunc_pointer = &myfunc_SSE41; // SSE4.1 version
|
|
else if (iset >= 2) myfunc_pointer = &myfunc_SSE2; // SSE2 version
|
|
else {
|
|
// Error: lowest instruction set not supported (put your own error message here:)
|
|
fprintf(stderr, "\nError: Instruction set SSE2 not supported on this computer");
|
|
return 0.f;
|
|
}
|
|
// continue in dispatched version
|
|
return (*myfunc_pointer)(f);
|
|
}
|
|
|
|
|
|
// Entry to dispatched function call
|
|
inline float myfunc(float * f) {
|
|
return (*myfunc_pointer)(f); // go to dispatched version
|
|
}
|
|
|
|
|
|
// Example: main calls myfunc
|
|
int main(int argc, char* argv[])
|
|
{
|
|
float a[16]={1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16}; // array of 16 floats
|
|
|
|
float sum = myfunc(a); // call function with dispatching
|
|
|
|
printf("\nsum = %8.3f \n", sum); // print result
|
|
return 0;
|
|
}
|
|
|
|
#endif // INSTRSET == 2
|
|
|