From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: Scalability of interface creation and deletion
Date: Sat, 07 May 2011 20:42:29 +0200
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Here is my trace here for one device deletion on one 8 core machine

[  800.447012] synchronize_rcu() in 15787 us
[  800.455013] synchronize_rcu() in 7682 us
[  800.464019] rcu_barrier() in 8487 us

Not that bad.

$ grep RCU .config
# RCU Subsystem
CONFIG_TREE_RCU=y
# CONFIG_PREEMPT_RCU is not set
CONFIG_RCU_TRACE=y
CONFIG_RCU_FANOUT=32
# CONFIG_RCU_FANOUT_EXACT is not set
# CONFIG_RCU_FAST_NO_HZ is not set
CONFIG_TREE_RCU_TRACE=y