Re: General performance of NAND operations i.e mount and ls

[Artem Bityutskiy <dedekind@infradead.org>]

On Thu, 2007-09-06 at 10:44 +0200, Konstantin Kletschke wrote:
> > Well, JFFS2 scans on mount, so no wonder it is that long. Summary should
> > improves the situation - do you have it enabled?
> 
> Summary is enabled in Kernel but I created the files with flash_eraseall
> and mounted the block device as jffs2 and copied the files onto it in
> system. So no summaryze, is that right?

Yup, summaries are there then.

> > I do not think you may make JFFS2 work faster on such big flash with
> > such big files, at least it will be difficult and would require core
> > jffs2 changes.
> 
> Okay, I wanted to check if the time is okay for 520MHz core with 104MHz
> Bus and 8Bit flash. If this is the case my Hardware driver is okay.
> There is no urge to improve this stat() time and fragtree building at
> the moment. If it takes so long and the driver is okay it wioll take so
> long (arguing with boss and customers :-)).

Try to measure raw R/W, e.g with dd. But beware dd will fail at the
first met bad block. Something like:

Read: dd if=/dev/mtd4 of=/dev/null bs=4096 count=512
Write: dd if=/dev/zero of=/dev/mtd4 bs=4096 count=512

It'll print raw R/W speed.  But beware dd will fail at the first bad
block, so yo may have to play with count= or skip= for read and seek=
for write to find a large enough contiguous area without bad blocks.

-- 
Best regards,
Artem Bityutskiy (Битюцкий Артём)