Hi,
On Mon, Mar 16, 2015 at 10:29:23AM +0100, Pascal Brand wrote:
Hello,
There are lots of uint64_t in the proposal, and I wonder how it will behaves on 32bits platforms, in terms of performances, ease to use,...
This interface is not intended to be used directly by client code, instead it's supposed to be wrapped in a client lib. I'm trying to follow the guide lines in https://www.kernel.org/doc/Documentation/ioctl/botching-up-ioctls.txt to avoid the need of having one 64-bit and one 32-bit api.
Thanks Jens for the doc. However, it does not really answer: do you know if there are any performance drop using u64 types instead of native type on 32bits platforms? Or we simply don't care?
My best guess would be no (noticable) impact on optimized code. On client side perhaps 1 extra instruction 64-bit per field on a call and on kernel side 0 or 1 extra instructions per 64-bit field.
-- Regards, Jens