Messages in this thread | | | From | Duncan Sands <> | Subject | Re: [linux-usb-devel] [PATCH 1/9] USB usbfs: take a reference to the usb device | Date | Sun, 18 Apr 2004 16:08:21 +0200 |
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Hi Oliver,
> Multiple interfaces are uncommon. Devices with several interfaces bound > to usbfs are uncommoner. Concurrent use is still uncommoner. You are > slowing the common case.
The slowdown is probably negligeable though. The speedup may be big for the rare cases where it matters (though I doubt anyone is ever going to care one way or the other).
> > > > (2) push the acquisition of dev->serialize down to the lower levels > > > > as they are fixed up. > > > > > > Why? > > > > Efficiency. The main reason is that the copy to/from user calls are > > inside the locked region :) As for the other places where the lock could > > be dropped, I guess measurement is required to see if it gains anything. > > OK. I see. But IMHO usbfs is not written for speed anyway, so don't > worry too much.
I'm not worrying! It's more a matter of hygiene :)
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