JFFS2 is broken

Vipin Malik vipin at embeddedlinuxworks.com
Tue Aug 14 13:57:43 EDT 2001

At 01:39 PM 8/14/2001 -0400, Frederic Giasson wrote:
>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.

But what about this other task _writing_ to JFFS2. How long does it block?
Plus is this still your code with liberally sprinkled schedules()?


>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
>   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 :)

More information about the linux-mtd mailing list