1. Mx6ul core module uses serial NAND FLASH read / write test (III)

The following is already in Iot-6ULX/EVB-6ULX The verification on the platform passed ,Iot-6ULX/EVB-6ULX Introduce the following ：

 

 2 Nand Flash Read and write test

test Nand Flash/eMMC Reading and writing speed , Mainly used dd Instructions . Instructions ：

dd Used to copy , Copy a file in a block of a specified size . from if（input file） File read out , writes of（output file） Specified file ,bs Is the size of each write block ,count Is the number of read-write blocks ."if=/dev/zero" Do not produce IO, That is, data can be output continuously , So it can be used to test pure write speed .

2.1 Nand Flash Write speed test

Nand Flash The root file system contains multiple directories , We need to select one of these directories to test . You can execute the following instructions to view the directories contained in the root directory .

[email protected] ~# cd /                         // Go to the root directory

roo[email protected] /# pwd                         // View the current directory

[email protected] /# ls                            // Displays the files and directories in the current directory

                                                              Contents under the root directory  

As you can see from the above figure , The root directory contains several subdirectories . among ,root The directory is the default directory when the system logs in （ Home directory ）. During the test , We enter root Test under the directory .

[email protected] /# cd /root                   // Enter root Catalog

[email protected] ~# pwd                      // View the current directory

                                                              Enter into root Under the table of contents

Use dd Command to root Write data to directory , And generate largefile file , File size is 80 MiB, Test write speed .

[email protected] ~# dd if=/dev/zero of=./largefile bs=8k count=10240 conv=fdatasync

                                                         Nand Flash Write speed test

From the information displayed on the terminal , The size of the file written is 80MiB, Speed is 36.2MB/s.

1.2.2 Nand Flash Read speed test

explain ： because Linux Kernel mechanism of , Generally, there is no need to release the used cache. these cache Content can increase the reading and writing speed of files .

The test process is to be able to test from Nand Flash Accurate speed of reading data in , So you need to clear the cache first .

Execute the following instructions , Clear cache ：

[email protected] ~# sh -c "sync && echo 3 > /proc/sys/vm/drop_caches"       // Clear page cache , Catalog entries and inode

                                                                          Clear cache

Again using dd The instruction reads with dd Instructions written largefile file , Test the reading speed ：

[email protected] ~# dd if=./largefile of=/dev/null bs=8k

                                                       Nand Flash Read speed test

From the information displayed on the terminal , The read file size is 80MiB, Speed is 33.6MB/s.

After the test is completed , Delete the test file with instructions ：

[email protected] ~# ls -alh largefile              // see largefile file

[email protected] ~# rm largefile                 // remove largefile file

                                                              Delete test file