jffs2

[Kári Davíðsson]

Hi,

> -----Original Message-----
> From: Vipin Malik [mailto:vipin.malik at daniel.com]
> Sent: 1. júní 2001 14:56
> To: Kári Davíðsson
> Cc: linux-mtd at lists.infradead.org
> Subject: Re: jffs2
> 
> 
> Kári Davíðsson wrote:
> 
> > Are there any known issues of running programs from a jffs2 
> partition?
> 
> Not that I know of.
> 
> 
> > I am attempting to run a program from a jffs2 partition (not root
> > partition which is mounted on /dev/ram)
> 
> Interesting choice of mount dir names (why "ram"?) :)

Well that is the initrd. I am limited in flash and I found that
compressing
a e2fs and mount it through the initrd mechanism gives me more space in
the
flash for a jffs2 partition that keeps the stuff I need to write to
flash 
during operation of board (logs, frequently changing configuration
files,
upgradable programs and drivers, etc).

> 
> 
> > and the program seem to be running extremely slow and what 
> is worse it
> > seem to block the kernel at the
> > same time, i.e. I can not ping the board nor telnet to it.
> 
> Not being able to ping it is bad. Not being able to telnet to it may
> depend on how much CPU resources are available
> to run the telnet daemon.

Yes, actually I found out it was a combination of two "bugs", one was
that I was running a very big (unstriped C++ program) in the range of
3.5 MB from the jffs2 partition, so I guess just uncompressing that kind
of file
takes its time. The second bug was another driver that disables
interrupts, was hanging.....

> 
> >
> >
> > If I wait long enough I get output from the program on the 
> console but
> > everything is very very slow.....
> >
> 
> What processor are you using? How big is your JFFS2 partition 

The processor is mpc823 running at 50Mhz, no powerhorse but a resonable
CPU for the things we are dooing.

> and what is

The jffs2 partition is 1.75 MB.

> this program that you are running doing?

Data acquizition.

>
> Remember that JFFS2 needs to go GC when the fs gets full (or 
> near full if
> the background GC task is running). If your program

How full is "near full" for the jffs2?

> is reading/writing from/to the JFFS2 fs it will get blocked. Are you
> generating a lot of data to the JFFS2 fs?

After I striped the executable, it is around 350kb everything is running
much better.

> 
> Vipin

Thanks,

K.D.