UM0851 datasheet(149/245 Pages) STMICROELECTRONICS

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UM0851

Non-volatile memory device drivers

Doc ID 16604 Rev 2

149/245

5.3.6

Serial NOR device driver performance

●

Hardware: ARM926EJS (333 MHz), STMicroelectronics 8 MB M25P64 Serial NOR

Flash.

●

Test Filesystem on the NAND Flash: JFFS2 (for /dev/mtdblock3)

●

Kernel: Linux-2.6.27

Results for JFFS2

Compression is on by default in JFFS2. This causes the writing of data, which is uniform, to

finish in much less time. Therefore compression was disabled from config.

Mount JFFS2 fs and write/read to a file. Sequence is as follows:

mount –t jffs2 /dev/mtdblock3 /mnt

time dd if=/dev/zero of=/mnt/file.bin bs=128K count=8 (Write the file)

umount /mnt

mount –t jffs2 /dev/mtdblock3 /mnt

time dd if=/mnt/file.bin of=/dev/null bs=128K count=8 (Read file back)

umount /mnt

mount –t jffs2 /dev/mtdblock3 /mnt

rm /mnt/file.bin

umount /mnt

10. Repeat for bs = 128K, 256K, 512K, 1024K and count=8, 4,2, 1.

Note:

Please be sure that JFFS2 compression is disabled. To disable it, use the following Linux

configuration parameter: CONFIG_JFFS2_CMODE_NONE.

Table 41.

Results on SPEAr600

Block size in

Kbytes

File size

in MB

Duration

(seconds)

in write

Mega

byte/sec in

write

Duration

(seconds) in

read

Mega byte/sec

in read

2.28

0.438596491

0.12

8.333333333

2.85

0.350877193

0.12

8.333333333

2.27

0.440528634

0.12

8.333333333

2.27

0.440528634

0.12

8.333333333

2.27

0.440528634

0.12

8.333333333

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