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Memory stick read speed is very low

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Noko

Joined: 06 Sep 2008
Posts: 23

Posted: Sat Sep 06, 2008 10:15 pm Post subject: Memory stick read speed is very low

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

Code:

#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("IOTEST", 0, 1, 1);
PSP_MAIN_THREAD_ATTR(THREAD_ATTR_USER | THREAD_ATTR_VFPU);

#define printf pspDebugScreenPrintf

int main(void){
struct timeval now,then;
char buffer[0x400];
SceIoStat stats;
SceUID f;

pspDebugScreenInit();

f=sceIoOpen("bgm15.ogg",PSP_O_RDONLY,0777);
gettimeofday(&now, NULL);
while(sceIoRead(f,buffer,sizeof(buffer)))
   ;
gettimeofday(&then, NULL);
sceIoClose(f);

sceIoGetstat("bgm15.ogg",&stats);

printf("took %ldms to read %lldKB",
   (then.tv_sec-now.tv_sec)*1000+(then.tv_usec-now.tv_usec)/1000,stats.st_size/0x400);

while(1)
   ;
}

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

Joined: 06 Sep 2008
Posts: 23

Posted: Sun Sep 07, 2008 12:51 am Post subject:

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

willow :--)

Joined: 13 Jan 2007
Posts: 126

Posted: Mon Sep 08, 2008 12:15 pm Post subject:

Noko wrote:

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.

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