Messages in this thread | | | Date | Thu, 13 Oct 2011 16:12:21 -0400 (EDT) | Subject | Re: [PATCH v7 0/8] Request for inclusion: tcp memory buffers | From | David Miller <> |
| |
From: Glauber Costa <glommer@parallels.com> Date: Fri, 14 Oct 2011 00:05:58 +0400
> Also, I kind of dispute the affirmation that !cgroup will encompass > the majority of users, since cgroups is being enabled by default by > most vendors. All systemd based systems use it extensively, for > instance.
I will definitely advise people against this, since the cost of having this on by default is absolutely non-trivial.
People keep asking every few releases "where the heck has my performance gone" and it's because of creeping features like this. This socket cgroup feature is a prime example of where that kind of stuff comes from.
I really get irritated when people go "oh, it's just one indirect function call" and "oh, it's just one more pointer in struct sock"
We work really hard to _remove_ elements from structures and make them smaller, and to remove expensive operations from the fast paths.
It might take someone weeks if not months to find a way to make a patch which compensates for the extra overhead your patches are adding.
And I don't think you fully appreciate that.
| |