On Sun, Oct 27, 2013 at 08:30:08AM -0400, Tejun Heo wrote:
>On Mon, Oct 21, 2013 at 04:58:11PM +0800, Wei Yang wrote:
>> When a cpu belongs to a new group, there is no cpu has the same group id.
>> This
>> means it can be assigned a new group id without checking with every others.
>>
>> This patch does this optimiztion.
>
>Does this actually matter? If so, it'd probably make a lot more sense
>to start inner loop at @cpu + 1 so that it becomes O(N).
One of the worst case in my mind:
CPU: 0 1 2 3 4 ...
Group: 0 1 2 3 4 ...
(sounds it is impossible in the real world)
Every time, when we encounter a new CPU and try to assign it to a group, we
found it belongs to a new group. The original logic will iterate on all old
CPUs again, while the new logic could skip this and assign it to a new group.
Again, this is a tiny change, which doesn't matters a lot.
BTW, I don't get your point for "start inner loop at @cpu+1".
The original logic is:
loop 1: 0 - nr_cpus
loop 2: 0 - (cpu - 1)
If you found one better approach to improve the logic, I believe all the users
will appreciate your efforts :-)
Thanks for your review and comments again ~
>
>Thanks.
>
>--
>tejun
--
Richard Yang
Help you, Help me
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
