Re: [PATCH v7 0/8] Request for inclusion: tcp memory buffers
[Posted December 6, 2011 by corbet]
| From: |
| David Miller <davem-AT-davemloft.net> |
| To: |
| glommer-AT-parallels.com |
| Subject: |
| Re: [PATCH v7 0/8] Request for inclusion: tcp memory buffers |
| Date: |
| Thu, 13 Oct 2011 16:12:21 -0400 (EDT) |
| Message-ID: |
| <20111013.161221.1969725742975317077.davem@davemloft.net> |
| Cc: |
| linux-kernel-AT-vger.kernel.org, akpm-AT-linux-foundation.org,
lizf-AT-cn.fujitsu.com, kamezawa.hiroyu-AT-jp.fujitsu.com,
ebiederm-AT-xmission.com, paul-AT-paulmenage.org, gthelen-AT-google.com,
netdev-AT-vger.kernel.org, linux-mm-AT-kvack.org, kirill-AT-shutemov.name,
avagin-AT-parallels.com, devel-AT-openvz.org |
| Archive‑link: | |
Article |
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.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
