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OCM vs DDR vs BRAM read/write speed

Former Member

Hi,

I executed an application that writes 8KB of data on OCM, DDR and BRAM for 2 Mega times (for each memory I wrote 16GB totally). I expected different memory speeds for OCM, DDR and BRAM but to my surprise all of these actions were done at the same time. I am using the memset() function for writing 8KB buffers. Anybody can explain it?

-Mohammad

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    Hi, there is my bare metal code for OCM and DDR Read/Write speed testing on zedboard.

    (0)We need some timer functions to record time
    int timer_read() {
    tint base, a;
    tbase = 0xf8002000;
    ta = REG_READ(base+0x18);
    treturn a;
    }
    double timer_value(int t, double fpclk) {
    t// t in timer units, fpclk in mhz
    t// returns timer value in seconds
    tdouble x;
    tx = ((double) t) * 65536.0 / (fpclk * 1000000.0);
    treturn x;
    }

    (1)Register set
    taddr_value(0xf8000910); // tttttttt slcr.OCM_CFG[RAM_HI] = 1000
    taddr_value(0xf8f00000); //mpcore.SCU_CONTROL_REGISTER[Address_filtering_enable] = 1
    taddr_value(0xf8f00040); //tt      mpcore.Filtering_Start_Address_Register = 0x0010_0000
    taddr_value(0xf8f00044); //ttt    mpcore.Filtering_End_Address_Register = 0xffe0_0000

    (2) prepare a random address offset data (stored in OCM) and write/read function
    tint random_offset[100] = {0x4700, 0x4300, 0x7300, 0x8600, 0x3600, 0x9600, 0x4700, 0x3600, 0x6100, 0x4600, 0x9900, 0x6900, 0x8100, 0x6200, 0x9700, 0x7400, 0x2400, 0x6700, 0x6200, 0x4200, 0x8100, 0x1400, 0x5700, 0x2000, 0x4200, 0x5300, 0x3200, 0x3700, 0x3200, 0x1600, 0x7600, 0x0200, 0x2700, 0x6600, 0x5600, 0x5000, 0x2600, 0x7100, 0x0700, 0x3200, 0x9000, 0x7900, 0x7800, 0x5300, 0x1200, 0x5600, 0x8500, 0x9900, 0x2600, 0x9600, 0x9600, 0x6800, 0x2700, 0x3100, 0x0500, 0x0300, 0x7200, 0x9300, 0x1500, 0x5500, 0x5900, 0x5600, 0x3500, 0x6400, 0x3800, 0x5400, 0x8200, 0x4600, 0x2200, 0x3100, 0x6200, 0x4300, 0x0900, 0x9000, 0x1600, 0x2200, 0x7700, 0x9400, 0x3900, 0x4900, 0x5400, 0x4300, 0x5400, 0x8200, 0x1700, 0x3700, 0x9300, 0x2300, 0x7800, 0x8400, 0x4200, 0x1700, 0x5300, 0x3100, 0x5700, 0x2400, 0x5500, 0x0600, 0x8800, 0x7700};

    Write/read function:
    #define REG_READ(addr)
    tt({int val;int a=addr; asm volatile ("ldr   %0,[%1]
    " : "=r"(val) : "r"(a)); val;})

    #define REG_WRITE(addr,val)
    tt({int v = val; int a = addr; __asm volatile ("str  %1,[%0]
    " :: "r"(a),"r"(v)); v;})


    (3) Test OCM, first prepare address:
    t//store random offset data in OCM block 2
    tint *ocm_data_int = 0x00010000;
    tfor(i = 0; i < 100 ; i++){
    ttocm_data_int[i] = OCM_BASE + random_offset[i];
    ttprint_addr_value(&ocm_data_int[i]);
    t}


    (3-1) Test OCM random write speed
            //random write 1.2GB data
    ttimer_init();
    tfor(j = 0; j<3145728; j++){ //2^20 = 1048576; 2^20 * 3 = 3145728
    ttfor(i=0; i<100; i++){
    tttREG_WRITE( ocm_data_int[i], 0xF0F00F0F);
    ttt//REG_WRITE( &ocm_data_int[i]+4, 0xF0F0000F);
    tt}
    t}
    ti = timer_read();
    ttest_time = timer_value(i, pclk);
    tprintf("     random write speed = %g MB/sr
    ", 1200.0/test_time);

    (3-2) Test OCM random read speed
    t// random read 1.2 GB data
    tint data_int=0;
    ttimer_init();
    tfor(j = 0; j<3145728; j++){ //2^20 = 1048576 (*3 = 3145728)
    ttfor(i=0; i<100; i++){
    tttdata_int = REG_READ(ocm_data_int[i]);
    tt}
    t}
    ti = timer_read();
    ttest_time = timer_value(i, pclk);
    tprintf("     random read speed = %g MB/sr
    ", 1200.0/test_time);


    (4) Test DDR, first we should prepare address as follows:
    tint DDR_BASE = 0x10020000;
    t//store random offset data in OCM block 2
    tfor(i = 0; i < 100 ; i++){
    ttocm_data_int[i] = DDR_BASE + random_offset[i];
    tt//print_addr_value(ocm_data_int[i]);
    t}

    (4-1) Test DDR random write speed
    ttimer_init();
    tfor(j = 0; j<3145728; j++){ //2^20 = 1048576 (*3 = 3145728)
    ttfor(i=0; i<100; i++){
    tttREG_WRITE( ocm_data_int[i], 0xF0F00F0F);
    tt}
    t}
    ti = timer_read();
    ttest_time = timer_value(i, pclk);
    tprintf("     random write speed = %g MB/sr
    ", 1200.0/test_time);

    (4-2) Test DDR random read speed
    ttimer_init();
    tfor(j = 0; j<3145728; j++){ //2^20 = 1048576 (*3 = 3145728)
    ttfor(i=0; i<100; i++){
    tttdata_int = REG_READ(ocm_data_int[i]);
    tt}
    t}
    ti = timer_read();
    tprintf("     random read time counter = %dr
    ", i);
    ttest_time = timer_value(i, pclk);
    tprintf("     random read 1.2GB time = %g secr
    ",  test_time);
    tprintf("     random read speed = %g MB/sr
    ", 1200.0/test_time);


    (5)Then I got the result:

         OCM random write speed = 498.653 MB/s
         OCM random read speed = 497.069 MB/s

         DDR  random write speed = 500.616 MB/s
         DDR  random read speed = 497.799 MB/s

    It seems like that there is not much difference between OCM and DDR for random WRITE/READ speed.

    Or, could you figure out that if there is any other problems?

    Thanks,
    Zeepen

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  • 0

    Hi, there is my bare metal code for OCM and DDR Read/Write speed testing on zedboard.

    (0)We need some timer functions to record time
    int timer_read() {
    tint base, a;
    tbase = 0xf8002000;
    ta = REG_READ(base+0x18);
    treturn a;
    }
    double timer_value(int t, double fpclk) {
    t// t in timer units, fpclk in mhz
    t// returns timer value in seconds
    tdouble x;
    tx = ((double) t) * 65536.0 / (fpclk * 1000000.0);
    treturn x;
    }

    (1)Register set
    taddr_value(0xf8000910); // tttttttt slcr.OCM_CFG[RAM_HI] = 1000
    taddr_value(0xf8f00000); //mpcore.SCU_CONTROL_REGISTER[Address_filtering_enable] = 1
    taddr_value(0xf8f00040); //tt      mpcore.Filtering_Start_Address_Register = 0x0010_0000
    taddr_value(0xf8f00044); //ttt    mpcore.Filtering_End_Address_Register = 0xffe0_0000

    (2) prepare a random address offset data (stored in OCM) and write/read function
    tint random_offset[100] = {0x4700, 0x4300, 0x7300, 0x8600, 0x3600, 0x9600, 0x4700, 0x3600, 0x6100, 0x4600, 0x9900, 0x6900, 0x8100, 0x6200, 0x9700, 0x7400, 0x2400, 0x6700, 0x6200, 0x4200, 0x8100, 0x1400, 0x5700, 0x2000, 0x4200, 0x5300, 0x3200, 0x3700, 0x3200, 0x1600, 0x7600, 0x0200, 0x2700, 0x6600, 0x5600, 0x5000, 0x2600, 0x7100, 0x0700, 0x3200, 0x9000, 0x7900, 0x7800, 0x5300, 0x1200, 0x5600, 0x8500, 0x9900, 0x2600, 0x9600, 0x9600, 0x6800, 0x2700, 0x3100, 0x0500, 0x0300, 0x7200, 0x9300, 0x1500, 0x5500, 0x5900, 0x5600, 0x3500, 0x6400, 0x3800, 0x5400, 0x8200, 0x4600, 0x2200, 0x3100, 0x6200, 0x4300, 0x0900, 0x9000, 0x1600, 0x2200, 0x7700, 0x9400, 0x3900, 0x4900, 0x5400, 0x4300, 0x5400, 0x8200, 0x1700, 0x3700, 0x9300, 0x2300, 0x7800, 0x8400, 0x4200, 0x1700, 0x5300, 0x3100, 0x5700, 0x2400, 0x5500, 0x0600, 0x8800, 0x7700};

    Write/read function:
    #define REG_READ(addr)
    tt({int val;int a=addr; asm volatile ("ldr   %0,[%1]
    " : "=r"(val) : "r"(a)); val;})

    #define REG_WRITE(addr,val)
    tt({int v = val; int a = addr; __asm volatile ("str  %1,[%0]
    " :: "r"(a),"r"(v)); v;})


    (3) Test OCM, first prepare address:
    t//store random offset data in OCM block 2
    tint *ocm_data_int = 0x00010000;
    tfor(i = 0; i < 100 ; i++){
    ttocm_data_int[i] = OCM_BASE + random_offset[i];
    ttprint_addr_value(&ocm_data_int[i]);
    t}


    (3-1) Test OCM random write speed
            //random write 1.2GB data
    ttimer_init();
    tfor(j = 0; j<3145728; j++){ //2^20 = 1048576; 2^20 * 3 = 3145728
    ttfor(i=0; i<100; i++){
    tttREG_WRITE( ocm_data_int[i], 0xF0F00F0F);
    ttt//REG_WRITE( &ocm_data_int[i]+4, 0xF0F0000F);
    tt}
    t}
    ti = timer_read();
    ttest_time = timer_value(i, pclk);
    tprintf("     random write speed = %g MB/sr
    ", 1200.0/test_time);

    (3-2) Test OCM random read speed
    t// random read 1.2 GB data
    tint data_int=0;
    ttimer_init();
    tfor(j = 0; j<3145728; j++){ //2^20 = 1048576 (*3 = 3145728)
    ttfor(i=0; i<100; i++){
    tttdata_int = REG_READ(ocm_data_int[i]);
    tt}
    t}
    ti = timer_read();
    ttest_time = timer_value(i, pclk);
    tprintf("     random read speed = %g MB/sr
    ", 1200.0/test_time);


    (4) Test DDR, first we should prepare address as follows:
    tint DDR_BASE = 0x10020000;
    t//store random offset data in OCM block 2
    tfor(i = 0; i < 100 ; i++){
    ttocm_data_int[i] = DDR_BASE + random_offset[i];
    tt//print_addr_value(ocm_data_int[i]);
    t}

    (4-1) Test DDR random write speed
    ttimer_init();
    tfor(j = 0; j<3145728; j++){ //2^20 = 1048576 (*3 = 3145728)
    ttfor(i=0; i<100; i++){
    tttREG_WRITE( ocm_data_int[i], 0xF0F00F0F);
    tt}
    t}
    ti = timer_read();
    ttest_time = timer_value(i, pclk);
    tprintf("     random write speed = %g MB/sr
    ", 1200.0/test_time);

    (4-2) Test DDR random read speed
    ttimer_init();
    tfor(j = 0; j<3145728; j++){ //2^20 = 1048576 (*3 = 3145728)
    ttfor(i=0; i<100; i++){
    tttdata_int = REG_READ(ocm_data_int[i]);
    tt}
    t}
    ti = timer_read();
    tprintf("     random read time counter = %dr
    ", i);
    ttest_time = timer_value(i, pclk);
    tprintf("     random read 1.2GB time = %g secr
    ",  test_time);
    tprintf("     random read speed = %g MB/sr
    ", 1200.0/test_time);


    (5)Then I got the result:

         OCM random write speed = 498.653 MB/s
         OCM random read speed = 497.069 MB/s

         DDR  random write speed = 500.616 MB/s
         DDR  random read speed = 497.799 MB/s

    It seems like that there is not much difference between OCM and DDR for random WRITE/READ speed.

    Or, could you figure out that if there is any other problems?

    Thanks,
    Zeepen

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