NAND read speeds on Linux 2.6.37

Ah well, looks like that's a "no". I'll keep an eye on the Git to see if the situation gets improved.

Ralph

Just wondering if there was any news on NAND read speed?

Thanks,
Ralph

Hi, isn't NAND polled prefetch the mode that's been used all along anyway?

Ralph

Oops, yes I see it was.

Update: NAND_OMAP_PREFETCH_POLLED now gives me 5MB/s. No big improvement but I suppose it's a start.

Thanks,

Ralph

The running system is am3517 500Mhz. and boot from SD card.

The Linux kernel is 2.6.37. 

I do some nand flash test by below command.

insmod /lib/modules/2.6.37-g01739e0-dirty/kernel/drivers/mtd/tests/mtd_speedtest.ko dev=5

Modified the file  /drivers/mtd/nand/omap2.c for different combination test.

        pdata->ecc_opt          = OMAP_ECC_HAMMING_CODE_HW;
//        pdata->ecc_opt          = OMAP_ECC_HAMMING_CODE_DEFAULT;
        pdata->xfer_type        = NAND_OMAP_PREFETCH_DMA;
//        pdata->xfer_type        = NAND_OMAP_POLLED;

It's weird  result  that the throughput is (SW ECC & DMA) > (HW ECC & PIO) > (HW ECC & DMA) .

Does anyone know why?

The detail test result is as below.

==================================================

HW ECC & DMA

[  119.938293] mtd_speedtest: MTD device: 5
[  119.942382] mtd_speedtest: MTD device size 382205952, eraseblock size 131072, page size 2048, count of eraseblocks 2916, pages per eraseblock 64, OOB size 64
[  119.961608] mtd_speedtest: scanning for bad eraseblocks
[  120.174682] mtd_speedtest: scanned 2916 eraseblocks, 0 are bad
[  124.238769] mtd_speedtest: testing eraseblock write speed
[  266.683654] mtd_speedtest: eraseblock write speed is 2598 KiB/s
[  266.689819] mtd_speedtest: testing eraseblock read speed
[  385.300231] mtd_speedtest: eraseblock read speed is 3121 KiB/s
[  389.364654] mtd_speedtest: testing page write speed
[  535.661804] mtd_speedtest: page write speed is 2530 KiB/s
[  535.667510] mtd_speedtest: testing page read speed
[  657.929687] mtd_speedtest: page read speed is 3028 KiB/s
[  661.993621] mtd_speedtest: testing 2 page write speed
[  806.135772] mtd_speedtest: 2 page write speed is 2568 KiB/s
[  806.141571] mtd_speedtest: testing 2 page read speed
[  926.559906] mtd_speedtest: 2 page read speed is 3074 KiB/s
[  926.565673] mtd_speedtest: Testing erase speed
[  930.628692] mtd_speedtest: erase speed is 91236 KiB/s
[  930.633941] mtd_speedtest: finished

==================================================

HW ECC & PIO

[   45.429870] mtd_speedtest: scanning for bad eraseblocks
[   45.643524] mtd_speedtest: scanned 2916 eraseblocks, 0 are bad
[   49.707214] mtd_speedtest: testing eraseblock write speed
[  189.160034] mtd_speedtest: eraseblock write speed is 2654 KiB/s
[  189.166229] mtd_speedtest: testing eraseblock read speed
[  277.977264] mtd_speedtest: eraseblock read speed is 4168 KiB/s
[  282.040924] mtd_speedtest: testing page write speed
[  424.620880] mtd_speedtest: page write speed is 2596 KiB/s
[  424.626525] mtd_speedtest: testing page read speed
[  516.346130] mtd_speedtest: page read speed is 4036 KiB/s
[  520.408782] mtd_speedtest: testing 2 page write speed
[  661.321777] mtd_speedtest: 2 page write speed is 2627 KiB/s
[  661.327667] mtd_speedtest: testing 2 page read speed
[  751.591369] mtd_speedtest: 2 page read speed is 4101 KiB/s
[  751.597076] mtd_speedtest: Testing erase speed
[  755.660064] mtd_speedtest: erase speed is 91236 KiB/s
[  755.665313] mtd_speedtest: finished

==================================================

SW ECC & DMA
[  119.329681] mtd_speedtest: MTD device: 5
[  119.333770] mtd_speedtest: MTD device size 382205952, eraseblock size 131072, page size 2048, count of eraseblocks 2916, pages per eraseblock 64, OOB size 64
[  119.352996] mtd_speedtest: scanning for bad eraseblocks
[  119.566314] mtd_speedtest: scanned 2916 eraseblocks, 0 are bad
[  123.631713] mtd_speedtest: testing eraseblock write speed
[  207.163970] mtd_speedtest: eraseblock write speed is 4432 KiB/s
[  207.170196] mtd_speedtest: testing eraseblock read speed
[  265.946350] mtd_speedtest: eraseblock read speed is 6298 KiB/s
[  270.013580] mtd_speedtest: testing page write speed
[  357.244201] mtd_speedtest: page write speed is 4244 KiB/s
[  357.249816] mtd_speedtest: testing page read speed
[  419.498687] mtd_speedtest: page read speed is 5947 KiB/s
[  423.562957] mtd_speedtest: testing 2 page write speed
[  508.785797] mtd_speedtest: 2 page write speed is 4344 KiB/s
[  508.791595] mtd_speedtest: testing 2 page read speed
[  569.252227] mtd_speedtest: 2 page read speed is 6123 KiB/s
[  569.258026] mtd_speedtest: Testing erase speed
[  573.321228] mtd_speedtest: erase speed is 91191 KiB/s
[  573.326477] mtd_speedtest: finished
[  573.330139] =================================================

Juan,

Have you also changed the "arch/arm/mach-omap2/board-flash.c" while updating the xfer type and ecc scheme. This file mentions these parameters in the "board_nand_init" function.

Regards,

Parth

Dear Parth,

Thanks much for your reply.

I don't change the board_nand_init().

Should I assign it again if equal am3517?

void
__init board_nand_init(struct mtd_partition *nand_parts,
                        u8 nr_parts, u8 cs, int nand_type)
{
        board_nand_data.cs              = cs; 
        board_nand_data.parts           = nand_parts;
        board_nand_data.nr_parts        = nr_parts;
        board_nand_data.devsize         = nand_type;

        board_nand_data.gpmc_irq = OMAP_GPMC_IRQ_BASE + cs; 

        if(cpu_is_omap3630())
                board_nand_data.ecc_opt = OMAP_ECC_HAMMING_CODE_HW;

        if (cpu_is_omap3517() || cpu_is_omap3505())
                board_nand_data.gpmc_t = NULL;

        if (cpu_is_ti81xx()) {
                board_nand_data.ecc_opt = OMAP_ECC_HAMMING_CODE_HW;
                board_nand_data.xfer_type = NAND_OMAP_POLLED;

                if (cpu_is_ti814x())
                        board_nand_data.gpmc_t = NULL;
        }

        gpmc_nand_init(&board_nand_data);
}

Juan,

Yes, i recommend you to add "board_nand_data.ecc_opt" and "board_nand_data.xfer_type" options inside "if (cpu_is_omap3517() || cpu_is_omap3505())".

Regards,

Parth

Dear Parth,

Thanks for your suggestion.

But the result is the same. 

Is there any possible?

        if (cpu_is_omap3517() || cpu_is_omap3505())
        {
                board_nand_data.ecc_opt = OMAP_ECC_HAMMING_CODE_HW;
//              board_nand_data.xfer_type = NAND_OMAP_POLLED;
                board_nand_data.xfer_type = NAND_OMAP_PREFETCH_DMA;
                board_nand_data.gpmc_t = NULL;
                printk("===================am3517\n");
        }

regards,

Ted

Dear Parth,

Do you have the test results for comparison?

Thanks very much.

regards,

Ted

Juan,

I do not support DMA xfer type and hence I have not done the comparison so far. We have tested "NAND_OMAP_PREFETCH_POLLED" which marginally increases performance as compared to "NAND_OMAP_POLLED".

Regards,

Parth

Dear Parth,

Thanks much for your information.

Do you use hw ecc or sw ecc?

How is the nand flash throughput that you test?

Thanks,

regards,

Ted

hi i tried as per your command dd if=/dev/mtd7ro of=/dev/null bs=1M count=100

but i am not able to see the speed n bytes copied.

is there ny other command available or how can i measure the read write performance for NAND in linux when linux as well as filesystem is flashed in NAND