From: Eric Dumazet <eric.dumazet@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: netdev <netdev@vger.kernel.org>, Tom Herbert <therbert@google.com>
Subject: Re: [PATCH v2 net-next] net: use jump_label to shortcut RPS if not setup
Date: Thu, 17 Nov 2011 22:34:49 +0100 [thread overview]
Message-ID: <1321565689.2444.5.camel@edumazet-laptop> (raw)
In-Reply-To: <1321535606.2751.35.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC>
Le jeudi 17 novembre 2011 à 14:13 +0100, Eric Dumazet a écrit :
> Most machines dont use RPS/RFS, and pay a fair amount of instructions in
> netif_receive_skb() / netif_rx() / get_rps_cpu() just to discover
> RPS/RFS is not setup.
>
> Add a jump_label named rps_needed.
>
> If no device rps_map or global rps_sock_flow_table is setup,
> netif_receive_skb() / netif_rx() do a single instruction instead of many
> ones, including conditional jumps.
>
> jmp +0 (if CONFIG_JUMP_LABEL=y)
>
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
> CC: Tom Herbert <therbert@google.com>
I wonder if we could use this jump_label infrastructure to shortcut
expensive netfilter nf_hook_slow() / nf_iterate on empty
tables/chains...
next prev parent reply other threads:[~2011-11-17 21:34 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-17 13:13 [PATCH v2 net-next] net: use jump_label to shortcut RPS if not setup Eric Dumazet
2011-11-17 21:34 ` Eric Dumazet [this message]
2011-11-17 22:04 ` David Miller
2011-11-17 22:19 ` Eric Dumazet
2011-11-17 22:06 ` David Miller
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