Re: [pyusb-users] Optimizing read/write speed

[wander.lairson <wan...@gm...>]

2011/5/11 Emmanuel BOUAZIZ <ebo...@ne...>:
> Hi Wander,
>
> thank you for your answer.
>
> I tried your patch and got no improvement.
>
> get_endpoint_type() on line 603 is now called with an interface number instead of an Interface object and passes that
> parameter to get_interface(), so the slow get_interface() call is made on line 183 instead of line 602.
>
> (get_interface() gets slow when it calls find_descriptor() which calls desc_iter())
>
> I don't see how to suppress the call to get_interface() in get_endpoint_type() as you need the bAlternateSetting attribute.
>
> Note that the solution of calling read() and write() with the Interface (which is easy to retrieve once for all) object
> instead of the interface number works fine so it's not a major issue.
>
> Also, when you reach line 609, you need to call fn() with intf instead of intf.bInterfaceNumber now.
>
Yes, you are right, I haven't realized that. It seems that to keep
things easy we can't run away of this kind of trade off..

Wander