From mboxrd@z Thu Jan  1 00:00:00 1970
From: Daniel Borkmann <daniel@iogearbox.net>
Subject: Re: [PATCH bpf-next v2 1/1] bpf, lpm: make longest_prefix_match()
 faster
Date: Thu, 22 Nov 2018 11:10:06 +0100
Message-ID: <e04fcc91-c8cd-ef94-82b2-d9c07cf43519@iogearbox.net>
References: <20181122053952.18244-1-edumazet@google.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Cc: netdev <netdev@vger.kernel.org>,
        Eric Dumazet <eric.dumazet@gmail.com>,
        Vlad Dumitrescu <vladum@google.com>
To: Eric Dumazet <edumazet@google.com>,
        Alexei Starovoitov <ast@kernel.org>
Return-path: <netdev-owner@vger.kernel.org>
Received: from www62.your-server.de ([213.133.104.62]:57554 "EHLO
        www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S2393869AbeKVUs5 (ORCPT
        <rfc822;netdev@vger.kernel.org>); Thu, 22 Nov 2018 15:48:57 -0500
In-Reply-To: <20181122053952.18244-1-edumazet@google.com>
Content-Language: en-US
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

On 11/22/2018 06:39 AM, Eric Dumazet wrote:
> At LPC 2018 in Vancouver, Vlad Dumitrescu mentioned that longest_prefix_match()
> has a high cost [1].
> 
> One reason for that cost is a loop handling one byte at a time.
> 
> We can handle more bytes at a time, if enough attention is paid
> to endianness.
> 
> I was able to remove ~55 % of longest_prefix_match() cpu costs.
> 
> [1] https://linuxplumbersconf.org/event/2/contributions/88/attachments/76/87/lpc-bpf-2018-shaping.pdf
> 
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Vlad Dumitrescu <vladum@google.com>
> Cc: Alexei Starovoitov <ast@kernel.org>
> Cc: Daniel Borkmann <daniel@iogearbox.net>

Looks good, applied to bpf-next, thanks!