Difference between revisions of "Rockpi4/hardware/emmc"

Revision as of 03:36, 15 May 2019

    ROCK Pi 4 >  Hardware >  eMMC Module

Introduction

ROCK Pi 4 doesn't come with on board storage, it uses the eMMC module instead. The benefits of eMMC module is the user can choose the storage as they need, it reduces the main board SKU for us. Also, pluggable eMMC module makes switching OS possible.

eMMC module

Note: the green PCB and black PCB are the same, just color difference.

The eMMC socket on ROCK Pi 4 uses two B2B connector to mount the eMMC module, the connector model is GB042 Series, one connector(34pin) for eMMC signal, the other(30pin) is for mount purpose only. This pinout of the 34pin is compatible with Odroid(Thanks Odroid for sharing their pinout).

• on ROCK Pi 4: GB042-34S-H10 (socket-34pin) + GB042-30S-H10 (socket-30pin)
• on eMMC module: GB042-34P-H10 (Plug-34pin) + GB042-30P-H10 (Plug-30pin)

The eMMC chip we use is branded as Foresee, by Longsys, a Shenzhen embedded storage company, who acquired Lexar Brand in 2017.

• Download Foresee eMMC chip test report

Benchmarks

Below is the test we did on different brand eMMC chips.

dd

   dd if=/dev/zero of=/dev/mmcblk1 bs=1G count=1 oflag=direct 
   dd if=/dev/mmcblk1 of=/dev/null bs=1G count=1

result:

|      | brand    | read    | write    |
| ---- | -------- | ------- | -------- |
| 8G   | Sandisk  | 270MB/s | 39.4MB/s |
| 16G  | Sandisk  | 230MB/s | 79.6MB/s |
| 16G  | Kingston | 160MB/s | 50.1MB/s |
| 16G  | Foresee  | 189MB/s | 74.4MB/s |
| 16G  | Foresee  | 241MB/s | 79.5MB/s |
| 32G  | Sandisk  | 263MB/s | 139MB/s  |
| 32G  | Samsung  | 263MB/s | 78.3MB/s |
| 32G  | Kingston | 152MB/s | 87.2MB/s |
| 64G  | Sandisk  | 207MB/s | 100MB/s  |
| 64G  | Foresee  | 215MB/s | 148MB/s  |
| 64G  | Foresee  | 194MB/s | 148MB/s  |
| 128G | Toshiba  | 217MB/s | 143MB/s  |

fio

1M Seq

   fio --name=write --ioengine=libaio --iodepth=4 --rw=write --bs=1M --direct=1 --size=2G --numjobs=30 --runtime=60 --group_reporting --filename=/dev/mmcblk1
   
   fio --name=read --ioengine=libaio --iodepth=4 --rw=read --bs=1M --direct=1 --size=2G --numjobs=30 --runtime=60 --group_reporting --filename=/dev/mmcblk1

4K random

   fio --name=randwrite --ioengine=libaio --iodepth=4 --rw=randwrite --bs=4K --direct=1 --size=2G --numjobs=30 --runtime=60 --group_reporting --filename=/dev/mmcblk1
   
   fio --name=randread --ioengine=libaio --iodepth=4 --rw=randread --bs=4K --direct=1 --size=2G --numjobs=30 --runtime=60 --group_reporting --filename=/dev/mmcblk1

result:

• Check full result at Github.

eMMC2sd adapter

With eMMC2sd adapter board, the user can write the image from PC with uSD card reader.