Memory stick read speed is very low

[Noko]

Here's the program I'm using to read file from memory stick:

Code: Select all

#include <pspkernel.h>
#include <pspdebug.h>
#include <pspctrl.h>
#include <stdlib.h>
#include <string.h>
#include <pspiofilemgr.h>
#include <time.h>
#include <sys/time.h>
#include <pspthreadman.h>

PSP_MODULE_INFO&#40;"IOTEST", 0, 1, 1&#41;;
PSP_MAIN_THREAD_ATTR&#40;THREAD_ATTR_USER | THREAD_ATTR_VFPU&#41;;

#define printf	pspDebugScreenPrintf

int main&#40;void&#41;&#123;
	struct timeval now,then;
	char buffer&#91;0x400&#93;;
	SceIoStat stats;
	SceUID f;

	pspDebugScreenInit&#40;&#41;;

	f=sceIoOpen&#40;"bgm15.ogg",PSP_O_RDONLY,0777&#41;;
	gettimeofday&#40;&now, NULL&#41;;
	while&#40;sceIoRead&#40;f,buffer,sizeof&#40;buffer&#41;&#41;&#41;
		;
	gettimeofday&#40;&then, NULL&#41;;
	sceIoClose&#40;f&#41;;
	
	sceIoGetstat&#40;"bgm15.ogg",&stats&#41;;
	
	printf&#40;"took %ldms to read %lldKB",
		&#40;then.tv_sec-now.tv_sec&#41;*1000+&#40;then.tv_usec-now.tv_usec&#41;/1000,stats.st_size/0x400&#41;;
	
	while&#40;1&#41;
		;
&#125;

And the output is ``took 3585ms to read 3364KB''. Now when I copy files from memorystick to my hard drive through USB the speed is roughly 5MB/s, 5 times better. Is something wrong with my code/psp, or is this correct behavior?

[Noko]

Ah, nevermind, I found the solution. Using larger buffer improves speed dramatically.

[willow :--)]

Ah, nevermind, I found the solution. Using larger buffer improves speed dramatically.

Yes. Most of the time, unless your file is really big, you'll want your buffer to be dynamically allocated to be the same size as the file, and read the file in one time.