Hi,
On Fri, Mar 23, 2012 at 12:41 PM, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> And I bet they are used wrong there. Again, unless you are in some very
> performance critical section of code, don't use unlikely().
>
> The big thing is that it just is not needed at all. Don't try to be
> smarter than the compiler if you don't need it, _AND_ you haven't
> actually measured it.
Nice answer. I did a quick grep and I found this scary result:
~/devel/v4l-dvb $ grep -r -n "unlikely(" drivers/ | wc -l
5018
I wonder perhaps we could add a check for unlikely in checkpatch script?
Something like: "are you sure about this"?
Also, perhaps this quote from [1] should be somewhere in Documentation:
"How should I use it ?
You should use it only in cases when the likeliest branch is very very
very likely, or when the unlikeliest branch is very very very
unlikely."
[1] http://kernelnewbies.org/FAQ/LikelyUnlikely
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