Re: UIO - interrupt performance

[Bill Gatliff <bgat@billgatliff.com>]

Wolfgang Grandegger wrote:
> Ben Nizette wrote:
>> On Tue, 2008-10-21 at 11:30 +0200, Marco Stornelli wrote:
>>> I could agree, but "the facto" due to UIO license condition, a company
>>> often uses UIO drivers, regardless performance, debug, etc, only as not
>>> to public the code under GPL.
>> It sounds to me like you think that driver authors can sit down and
>> decide whether they want to implement their driver in userspace or
>> kernel space.  For 99% of drivers that's simply not true.  You  *cannot*
>> write userspace drivers for most hardware, the hooks just aren't
>> available.  UIO is Userspace I/O, not a set of general hooks for
>> userspace drivers.
> 
> I known, fortunately it's not that simple or even feasible. Image a
> network driver with I/O multiplexing used by various processes.

Actually, UIO is pretty useful for that when combined with tun/tap.

> That's *not* an option, please read the GPL license conditions. At least
> it's legal gray area. Note that it's not my intention to start a
> discussion on that.

Then I will only contradict you, and not cite my supporting evidence.  :)


b.g.
-- 
Bill Gatliff
bgat@billgatliff.com