From: Hans de Goede <j.w.r.degoede@hhs.nl>
To: David Miller <davem@davemloft.net>
Cc: andi@firstfloor.org, dada1@cosmosbay.com, davej@redhat.com,
netdev@vger.kernel.org
Subject: Re: cat /proc/net/tcp takes 0.5 seconds on x86_64
Date: Thu, 28 Aug 2008 10:12:13 +0200 [thread overview]
Message-ID: <48B65DDD.6020309@hhs.nl> (raw)
In-Reply-To: <20080828.005909.215643947.davem@davemloft.net>
David Miller wrote:
> From: Andi Kleen <andi@firstfloor.org>
> Date: Thu, 28 Aug 2008 09:45:36 +0200
>
>>> When scanning route cache hash table, we can avoid taking locks for empty
>>> buckets.
>> I'm not sure it's worth it in this case. A rcu_read_lock() is a nop
>> (on non preemptible kernel) to very cheap (non atomic increment/decrement in
>> cached task_struct)
>
> It's not one, it's at least two such increments, plus function calls,
> state checks, etc. since this is rcu_read_lock_bh().
>
I'm very happy to see some progress on this and this leading to even more
optimalizations elsewhere,
Thanks guys!
Regards,
Hans
p.s.
Can I please be removed from the CC, thanks!
next prev parent reply other threads:[~2008-08-28 8:01 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-459782-176318@bugzilla.redhat.com>
[not found] ` <200808261549.m7QFnVUN032543@bz-web1.app.phx.redhat.com>
2008-08-26 16:37 ` cat /proc/net/tcp takes 0.5 seconds on x86_64 Dave Jones
2008-08-26 18:32 ` Eric Dumazet
2008-08-26 19:01 ` Hans de Goede
2008-08-26 20:39 ` Eric Dumazet
2008-08-26 20:58 ` Hans de Goede
2008-08-26 21:27 ` Eric Dumazet
2008-08-27 9:14 ` Hans de Goede
2008-08-27 9:05 ` David Miller
2008-08-27 9:45 ` Hans de Goede
2008-08-27 9:39 ` David Miller
2008-08-27 4:19 ` Herbert Xu
2008-08-27 9:07 ` Hans de Goede
2008-08-27 12:41 ` Andi Kleen
2008-08-27 21:29 ` Trent Piepho
2008-08-27 21:47 ` Andi Kleen
2008-08-27 22:54 ` Andi Kleen
2008-08-27 21:29 ` David Miller
2008-08-27 21:48 ` Stephen Hemminger
2008-08-27 22:09 ` David Miller
2008-08-28 6:20 ` Eric Dumazet
2008-08-28 6:51 ` David Miller
2008-08-28 7:13 ` Eric Dumazet
2008-08-28 7:57 ` David Miller
2008-08-28 9:52 ` Eric Dumazet
2008-08-28 7:26 ` Andi Kleen
2008-08-27 22:34 ` Andi Kleen
2008-08-27 22:39 ` David Miller
2008-08-27 22:57 ` Andi Kleen
2008-08-27 23:07 ` David Miller
2008-08-27 23:09 ` Eric Dumazet
2008-08-27 23:15 ` David Miller
2008-08-27 23:35 ` Andi Kleen
2008-08-27 23:43 ` Eric Dumazet
2008-08-27 23:45 ` David Miller
2008-08-28 0:40 ` Eric Dumazet
2008-08-28 7:45 ` Andi Kleen
2008-08-28 7:59 ` David Miller
2008-08-28 8:12 ` Hans de Goede [this message]
2008-08-28 8:04 ` David Miller
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