On Mon, 2007-10-15 at 12:32 +0200, Detlev Zundel wrote:
Hi Matt,
I'm got an AT91RM9200 and an 16 MB ST Micro NAND flash, partitioned into 3 blocks of 8, 4 and 4 MB. U-boot boots linux from the first 8MB partition, and doesn't go searching in the others unless it's necessary.
The JFFS2 scan for this takes 1:45. I believe I followed all the instructions in the docs for setting up the NAND flash, and other than seeming to be really slow, it seems to operate just fine.
When I use nand write.jffs2 to write the image, it doesn't take nearly this long.
Has anyone else had a similar experience? Is there some configuration or other tip someone might be able to give me as to why this is so slow?
As mentioned several times on this mailing list, this is a "feature" of the data structures used by JFFS2. So as not to repeat myself too much, JFFS2 has to find the "current" data blocks for the files urging it to scan the whole partition.
This is not entierly true. The scaning can be made much faster. There was/is a patch on the ML that improves the scaning speed significantly. Search for subject "jffs2 fsload - SOLVED" Not sure if that patch impl. reduced scanning of empty EBs, scanning all empty space is very time consuming.
Jocke
A simple workaround - also mentioned a few times already - is to use a small partition for what is needed during booting.
Cheers Detlev