From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [PATCH v6] net: batch skb dequeueing from softnet
 input_pkt_queue
Date: Mon, 03 May 2010 07:17:14 +0200
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Cc: Andi Kleen <andi@firstfloor.org>,
	David Miller <davem@davemloft.net>, hadi@cyberus.ca,
	xiaosuo@gmail.com, therbert@google.com, shemminger@vyatta.com,
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To: Arjan van de Ven <arjan@infradead.org>
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Le dimanche 02 mai 2010 =C3=A0 20:50 -0700, Arjan van de Ven a =C3=A9cr=
it :

> we effectively do that. The thing is that C2 is so low cost normally
> that it's still worth it even at 20k wakeups...
>=20
> this is where the bios tells us how "heavy" the states are....
> and 64 usec... is just not very much.

Maybe its low cost, (apparently, it is, since I can reach ~900.000 ipis
on my 16 cores machine) but multiply this by 16 or 32 or 64 cpus, and
clockevents_notify() cost appears to be a killer, all cpus compete on a
single lock.

Maybe this notifier could use RCU ?