Hi,
I’m confused when I use memcpy() in pandaboard android. The test code is very simple, as below:
#define PER_COPY_SIZE (1024*1024*4)
int main(int argc, char *argv[ ]){
char *src;
char *dst;
char *p;
src=(char *)malloc(PER_COPY_SIZE);
dst=(char*)malloc(PER_COPY_SIZE);
p=src;
#if 1
for(int i=0; i<PER_COPY_SIZE; i++){
*p++=i%255;
}
#endif
for(int j=0; j<1000; j++){
memcpy(dst, src, PER_COPY_SIZE);
}
free(src);
free(dst);
return 0;
}
It copies 4M byte data from source to dest repeatedly and takes 12 seconds. But when I get rid of the part of code in red color, it takes only 4 seconds. Why does the writing to source firstly has influence the memcpy( ) time so greatly?
Thanks & Best Regards!
牟刚
Actions Semiconductor Co.,Ltd
Tel: +86-756-3392353 ext.3103 Fax: +86-756-3392251
Email: mugang(a)actions-semi.com HTTP://www.actions-semi.com
________________________________
发件人: 牟刚
发送时间: 2012年10月30日 16:04
收件人: 'linaro-android(a)lists.linaro.org'
主题: pandaboard GPU driver
Hi，
I want compile pandaboard GPU driver myself and get the library, such as “libEGL_POWERVR_SGX540_120.so”, “libIMGegl.so” and so on. How can I get the GPU driver source code and compile environment?
Thanks & Best Regards!
牟刚
Actions Semiconductor Co.,Ltd
Tel: +86-756-3392353 ext.3103 Fax: +86-756-3392251
Email: mugang(a)actions-semi.com HTTP://www.actions-semi.com
