MMC (write) speed

Wim De Witte

Using latest kernel, I noticed slow MMC access. Our board supports both eMMC and micro-SD-card memory.

On both memories, an ext4 fs is installed and mounted with default options. I measured write speeds of about 2MBytes/sec on both flash media.

According to the performance guide http://processors.wiki.ti.com/index.php/AM335x-PSP_04.06.00.07_Features_and_Performance_Guide roughly 8MB should be possible.

I merged also following patch: http://arago-project.org/git/projects/?p=linux-am33x.git;a=commit;h=36800bd1ae85fd459f348323c630fd173a18ba4b

In the board setup file I added following capability: MMC_CAP_4_BIT_DATA

Electrical signals are looking fine on a scope.

Kernel log:

[    1.319458] mmc0: host does not support reading read-only switch. assuming write-enable.
[    1.330474] mmc0: new high speed SDHC card at address 1234
[    1.336700] mmcblk0: mmc0:1234 SA04G 3.63 GiB
[    1.344299] mmcblk0: p1 p2 p3 p4
[    1.427307] mmc1: new high speed MMC card at address 0001
[    1.433410] usb 2-1: new high-speed USB device number 2 using musb-hdrc
[    1.440612] mmcblk1: mmc1:0001 HYNIX 1.68 GiB
[    1.445648] mmcblk1boot0: mmc1:0001 HYNIX partition 1 1.00 MiB
[    1.451995] mmcblk1boot1: mmc1:0001 HYNIX partition 2 1.00 MiB
[    1.460449] mmcblk1: p1 p2 p3 p4
[    1.466766] mmcblk1boot1: unknown partition table
[    1.473602] mmcblk1boot0: unknown partition table

Question:

Does anyone have a suggestion to improve (write) speed?

Best regards,

Wim

over 13 years ago

0 Gururaja Hebbar over 13 years ago

TI__Intellectual 2725 points

Few clarifications needed

1. What is the Card type (SDHC Class ?) and manufacturer

2. have you tried with different cards?

3. i believe the cards are mounted in async option

4. The performance figures are for SanDisk "Extreme HIGH speed" cards. They deliver eight times faster than ordinary memory cards

Regards

Gururaja

0 Wim De Witte over 13 years ago in reply to Gururaja Hebbar

Intellectual 300 points

Hi Gururaja,

the device will use eMMC (e-NAND) memory from Hynix H26M21001ECR. The SD card is only used for development.

The datasheet is not very complete about bandwith specification in several modes, I cannot find hard numbers.

fs is indeed in async mode

I shall also use a sandisk for testing and measuring bandwidths.

Regards,

Wim

0 Renjith Thomas over 13 years ago in reply to Wim De Witte

Guru 31670 points

Hi Wim,

We've achieved 13.55MB/sec throughput in OMAP4430 Blaze board before. We've also achieved quite NAND read speeds of 8MB/sec on Netra platform. We've also good experience in driver optimization. If you are seriously looking to improve the throughput please get in touch with us.

renjith.thomas@pathpartnertech.com

0 Gangadhar Gangu over 10 years ago in reply to Renjith Thomas

Expert 1865 points

Hi Renjith Thomas,
Please tell me how to measure emmc read and write speeds. My post - e2e.ti.com/.../409887

Regards,
Gangadhar

0 Gangadhar Gangu over 10 years ago in reply to Gangadhar Gangu

Expert 1865 points

Hi Renjith,
I want LFTB(Linux functional test bench) scripts to measure emmc read/write speed. I searched in TI site. I could not find it. It'll be a great help if you can send me the link to download.

Regards,
Gangadhar

0 Mark Utter over 10 years ago in reply to Gangadhar Gangu

TI__Expert 7155 points

Ganagadhar,

I found this link:
processors.wiki.ti.com/.../Sitara_PSP_Test_Setup

Regards,
Mark

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MMC (write) speed