[Techteam] weekend 10/10

Tomeu Vizoso tomeu at tomeuvizoso.net
Wed Oct 15 05:00:08 EDT 2008

On Wed, Oct 15, 2008 at 3:11 AM, Deepak Saxena <dsaxena at laptop.org> wrote:
> On Oct 10 2008, at 11:44, Tomeu Vizoso was caught saying:
>> - when the filesystem gets less empty, the jffs2 gc thread has to work
>> a lot and steals a considerable amount of cpu to the rest of the
>> software. Try filling your nand to leave "just" 200MB free and monitor
>> while you use Sugar which processes take cpu in a ssh session, you'll
>> see the gc thread pretty active there and the other processes will
>> spend quite a bit of time in the kernel as well.
> Note that UBIFS (and any flash fs by that matter) has the same issues;
> however UBI should peform better as we fill up. We'll know more once we
> start running some tests and gathering data.

Sounds good, I hope UBI will perform much better as AFAIK the plan has
been that the machine would have always the flash mostly full. Old
stuff would be removed as new stuff gets added.

>> - most of the files that the user will save during the use of Sugar
>> will be already compressed (png, jpeg, pdf, zip, ogg, etc) and we are
>> compressing and decompressing them again and again. We cannot waste
>> cpu like that.
> If the majority of the files in /home are going to be pre-compressed,
> can we just mount /home with no compression at all?

Sounds pretty good to me.



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