JFFS2 is broken

[Frederic Giasson]

Good news!  

The jitter is now down to 3 seconds. 
In my test I ran JitterTest as a RT task reading I/P from jffs2.

When I run JitterTest with another task running in background which writes
to JFFS2, the jitter is up to 5 seconds.  No more 40 seconds waiting.


Frédéric Giasson





-----Original Message-----
From: Vipin Malik [mailto:vipin at embeddedlinuxworks.com]
Sent: Monday, August 13, 2001 10:40 PM
To: David Woodhouse
Cc: Frederic Giasson; MTD mailing list (E-mail)
Subject: Re: JFFS2 is broken 


At 01:00 AM 8/14/2001 +0100, David Woodhouse wrote:

>vipin at embeddedlinuxworks.com said:
> > David once mentioned that there are some obvious optimizations that
> > can be carried out in the JFFS2 code. Maybe he could list out his
> > favorite ones  and maybe someone could volunteer to tackle them one by
> > one.
>
>I committed the cleanup to jffs2_remove_node_refs_from_ino_list()

Great! Frederic, since you just setup your system to do the jitter tests, 
could you pl run them again (with the new code from CVS) and see what 
difference it made (my own system is busy running the mird db power fail 
tests).

  Also enable profiling and see what else is on the  "CPU hog" list.

The LTT (Linux Trace Toolkit) seems to be an excellent tool to get more 
fine grained performance stats out of the system and
a new version was just released for 2.4.5 (though it may provide us with 
more info that we need/can handle :)

Vipin