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Re: JFFS2 (NAND) mount time improvment

On Wed, Aug 18, 2004 at 11:37:33PM +0200, ext Ferenc Havasi wrote:
> We tried to modify only jffs2_scan_eraseblock to read less NAND page 
> than before.

I tried this patch on a test board running Omap 1710 @ 192 MHz and 
with 1 Gbit NAND flash, using internal HW nand flash controller on
Omap. I use 2.6.9-rc1-omap1 kernel, patched with CVS September 7th snapshot
and then applied Ferenc's patch.

The raw read speed using dd through /dev/mtd is about 1.8MiB/s.  Reading 
the whole 122MiB partition takes about 68s using dd bs=2k.  The fs is 35% 
full and with plain 2.6.9-rc1-omap1 the mount time is 20s.

After applying Ferenc's patch I created the filesystem image 

  mkfs.jffs2 -e 128 -l -n  -d foo -o bar

I then flashed the test partition with the image just created, rebooted the 
board with kernel that contained the new scan code and mounted the test 
partition.  The mount increased from 20s to 82s.  This is even more
than to read the whole device through dd.

Something is wrong. Did I use correct options to create the image? There
does not seem to be flash page size option anymore. I don't use
cleanmarker in the image as the flasher will write it to the first
OOB of each erase block.

I thins the next logical thing to do is to try to profile, where
the time is spent and what might cause qudruple times increase in mount

Jarkko Lavinen

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