From: Eric Dumazet <dada1@cosmosbay•com>
To: Benjamin LaHaise <bcrl@lhnet•ca>
Cc: Denys Fedoryschenko <denys@visp•net.lb>, netdev@vger•kernel.org
Subject: Re: regression: unregister_netdev() unusably slow
Date: Mon, 25 May 2009 00:47:39 +0200 [thread overview]
Message-ID: <4A19CE8B.3070302@cosmosbay.com> (raw)
In-Reply-To: <20090524221240.GI24757@kvack.org>
Benjamin LaHaise a écrit :
> On Mon, May 25, 2009 at 12:07:07AM +0200, Eric Dumazet wrote:
>> Maybe your HZ is too low ? Changing to 1000 HZ helps a lot
>
> HZ is set to 1000. I turned off CONFIG_NO_HZ
>
>> Also your hotplug config might do strange things at device removal ?
>
> If it were CPU bound, maybe, but this behaviour is tied to the kernel
> version in use.
>
>> What distro do you use ?
>
> It's an older Fedora 7 install inside kvm on a Fedora 10 host running
> 2.6.30-rc7.
>
OK thanks
I switched HZ from 250 to 1000 and got :
time ip link del vlan.899
real 0m0.011s
user 0m0.000s
sys 0m0.002s
There is a strong dependancy against HZ
BTW, I am using TREE_RCU
# RCU Subsystem
# CONFIG_CLASSIC_RCU is not set
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_TREE_RCU_TRACE=y
# CONFIG_PREEMPT_RCU_TRACE is not set
# CONFIG_RCU_TORTURE_TEST is not set
# CONFIG_RCU_CPU_STALL_DETECTOR is not set
next prev parent reply other threads:[~2009-05-24 22:47 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-24 19:21 regression: unregister_netdev() unusably slow Benjamin LaHaise
2009-05-24 21:23 ` Denys Fedoryschenko
2009-05-24 21:37 ` Benjamin LaHaise
2009-05-24 21:42 ` Eric Dumazet
2009-05-24 21:44 ` Benjamin LaHaise
2009-05-24 22:07 ` Eric Dumazet
2009-05-24 22:12 ` Benjamin LaHaise
2009-05-24 22:47 ` Eric Dumazet [this message]
2009-05-25 0:00 ` Benjamin LaHaise
2009-05-25 5:22 ` Eric Dumazet
2009-05-25 8:04 ` Damien Wyart
2009-05-25 16:21 ` Paul E. McKenney
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