The performance of mimalloc is unexpectedly lower than that of the system's built-in allocator.

[litterbug23]

Test Envirment: Windows 10 , MSVC 2017 x86
system malloc: 59000 (ms)
mimalloc 92000 (ms):

#include <mimalloc.h>
#include <ctime>
#include <iostream>
typedef uint32_t u32;
typedef float f32;
u32 getMicrosecondsCPU()
{
	clock_t newClock = clock();
	return (u32)((f32)(newClock) / ((f32)CLOCKS_PER_SEC / 1000000.0));
}

int main(int argc, char** argv) {
	u32 time1= getMicrosecondsCPU();
#pragma omp parallel for num_threads(6) // NEW ADD
		for (int i = 0; i < 1000000; i++)
		{
			//void* pppp = _aligned_malloc(1024, 8);
			//_aligned_free(pppp);
			void* pppp = malloc(1024);
			free(pppp);
		}
		u32 time2 = getMicrosecondsCPU();
		std::cout << "system malloc:" << (time2 - time1) << std::endl;
	}
	{
		u32 time1 = getMicrosecondsCPU();
#pragma omp parallel for num_threads(6) // NEW ADD
		for(int i = 0; i < 1000000; i++)
		{
			void* pppp = mi_malloc(1024);
			mi_free(pppp);
		}
		u32 time2 = getMicrosecondsCPU();
		std::cout <<"mimalloc: " <<  (time2 - time1) << std::endl;
	}
}

[mjp41]

You have chosen a benchmark size just above the threshold for small allocations.

mimalloc/doc/mimalloc-doc.h

Line 253 in 4e50d67

#define MI_SMALL_SIZE_MAX (128*sizeof(void*))

Do you see the same performance with 1024? It would be useful if you submitted your performance numbers with your issue, and removed the dead/commented code from the sample.

If you begin the code with
```C++
and end it with
```
then it will be easier to read.

[litterbug23]

Test Enviroment: windows 10 ,msvc 2017,x86
If a new problem is found, where memory is only allocated but not released, the performance will be even lower. lower 10x
sys malloc: 59000
mimalloc: 534000

I don't know Why? It's very simple test.

	{
		u32 time1 = getMicrosecondsCPU();
#pragma omp parallel for num_threads(6) // NEW ADD
		for(int i = 0; i < 1000000; i++)
		{
			void* pppp = mi_malloc(1024);
		}
		u32 time2 = getMicrosecondsCPU();
		std::cout << (time2 - time1) << std::endl;
	}

[litterbug23]

Test Enviroment: CPU: Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz , Windows 10 19045.3448

Recompile mimalloc x64, is faster than system malloc.

os malloc: 68000
mimalloc: 19000

Recompile mimalloc win32, is slower than system malloc.

os malloc: 59000 (ms)
mimalloc: 92000 (ms):

Why x64 is faster than x86 ?