From: David Miller <davem@davemloft.net>
To: shemminger@vyatta.com
Cc: ebiederm@xmission.com, tj@kernel.org, mingo@elte.hu,
rusty@rustcorp.com.au, herbert@gondor.apana.org.au,
akpm@linux-foundation.org, hpa@zytor.com, brgerst@gmail.com,
cl@linux-foundation.org, travis@sgi.com,
linux-kernel@vger.kernel.org, steiner@sgi.com, hugh@veritas.com,
netdev@vger.kernel.org, mathieu.desnoyers@polymtl.ca
Subject: Re: [PATCH] percpu: add optimized generic percpu accessors
Date: Wed, 21 Jan 2009 12:34:20 -0800 (PST) [thread overview]
Message-ID: <20090121.123420.145043842.davem@davemloft.net> (raw)
In-Reply-To: <20090121234502.66acbcf9@s6510>
From: Stephen Hemminger <shemminger@vyatta.com>
Date: Wed, 21 Jan 2009 23:45:01 +1100
> This is crap. only a small fraction of these SNMP counters are
> close enough to the hot path to deserve per-cpu treatment.
Only if your router/firewall/webserver isn't hitting that code path
which bumps the counters you think aren't hot path.
It's a micro-DoS waiting to happen if we start trying to split
counters up into groups which matter for hot path processing
(and thus use per-cpu stuff) and those which don't (and thus
use atomics or whatever your idea is).
prev parent reply other threads:[~2009-01-21 20:34 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20090115183942.GA6325@elte.hu>
[not found] ` <20090116001200.GA9137@gondor.apana.org.au>
[not found] ` <20090116001544.GA11073@elte.hu>
2009-01-16 0:18 ` [PATCH] percpu: add optimized generic percpu accessors Herbert Xu
[not found] ` <200901170827.33729.rusty@rustcorp.com.au>
2009-01-16 22:08 ` Ingo Molnar
[not found] ` <200901201328.24605.rusty@rustcorp.com.au>
2009-01-20 6:25 ` Tejun Heo
2009-01-20 10:36 ` Ingo Molnar
[not found] ` <200901271213.18605.rusty@rustcorp.com.au>
2009-01-27 2:24 ` Tejun Heo
2009-01-27 13:13 ` Ingo Molnar
2009-01-27 23:07 ` Tejun Heo
2009-01-28 3:36 ` Tejun Heo
2009-01-28 8:12 ` Tejun Heo
2009-01-27 20:08 ` Christoph Lameter
2009-01-27 21:47 ` David Miller
2009-01-27 22:47 ` Rick Jones
2009-01-28 0:17 ` Luck, Tony
2009-01-28 16:48 ` Christoph Lameter
2009-01-28 17:15 ` Luck, Tony
2009-01-28 16:45 ` Christoph Lameter
2009-01-28 20:47 ` David Miller
2009-01-28 10:38 ` Rusty Russell
2009-01-28 10:56 ` Tejun Heo
2009-01-29 2:06 ` Rusty Russell
2009-01-31 6:11 ` Tejun Heo
2009-01-28 16:50 ` Christoph Lameter
2009-01-28 18:07 ` Mathieu Desnoyers
2009-01-29 18:33 ` Christoph Lameter
2009-01-29 18:48 ` H. Peter Anvin
2009-01-20 10:40 ` Ingo Molnar
2009-01-21 5:52 ` Tejun Heo
2009-01-21 10:05 ` Ingo Molnar
2009-01-21 11:21 ` Eric W. Biederman
2009-01-21 12:45 ` Stephen Hemminger
2009-01-21 14:13 ` Eric W. Biederman
2009-01-21 20:34 ` David Miller [this message]
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