Marco Pesenti Gritti wrote:
Mitch Bradley wrote:
The processor on OLPC is inherently slower than the processors that
are used in modern laptops. To get ultra low power you have to
sacrifice something. It seems unlikely that we would be able to hide
that inherent speed differential by a kernel change. In the short
term, I don't know of any planned hardware changes that would
substantially increase the performance of file system activity on USB
drives.
Ok, this is the kind of feedback I was looking for. What about the
internal flash? Is it going to be substantially faster than USB drives?
I wouldn't count on it being enough faster to make a huge difference in
the case you are investigating. I expect that the process is mostly
CPU-bound. Somebody correct me if I'm wrong, but the kernel buffer
cache is probably preventing most of those failed opens from having to
re-access the USB hardware.
You could test that easily; just create/mount a tmpfs (RAM-resident)
directory and try your script on it.
I believe that "work smarter" is a key component of the OLPC plan. It
looks like you have found some "low-hanging fruit" that is ripe for
the picking. Improving pygtk to start up in a less "brute force" way
would benefit not only OLPC, but everybody else as well.
Definitely. But it's also important to prioritize the work. The whole
point of this mail is to figure out how critical the "opening a bunch
of files" issues is going to be on the final hardware/kernel.
The current hardware and kernel is a reasonable model for the speed of
the final system. We'll certainly make some improvements to the core
performance of the low-level system, but it won't be an order of
magnitude*. So order of magnitude speedups will have to come from
avoiding unnecessary work, rather than depending on the system to be so
fast that waste doesn't matter.
*I am, however, confident that we can make huge improvements in the
stability.
Thanks,
Marco
_______________________________________________
Sugar mailing list
[email protected]
http://mailman.laptop.org/mailman/listinfo/sugar
