From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [net-next PATCH 0/4] fib_trie: Remove leaf_info structure Date: Fri, 27 Feb 2015 17:06:03 -0500 (EST) Message-ID: <20150227.170603.1872259963520922972.davem@davemloft.net> References: <20150225185658.1747.99188.stgit@ahduyck-vm-fedora20> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, ja@ssi.bg To: alexander.h.duyck@redhat.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:54569 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755191AbbB0WGI (ORCPT ); Fri, 27 Feb 2015 17:06:08 -0500 In-Reply-To: <20150225185658.1747.99188.stgit@ahduyck-vm-fedora20> Sender: netdev-owner@vger.kernel.org List-ID: From: Alexander Duyck Date: Wed, 25 Feb 2015 11:05:55 -0800 > This patch set removes the leaf_info structure from the IPv4 fib_trie. The > general idea is that the leaf_info structure itself only held about 6 > actual bits of data, beyond that it was mostly just waste. As such we can > drop the structure, move the 1 byte representing the prefix/suffix length > into the fib_alias and just link it all into one list. > > My testing shows that this saves somewhere between 4 to 10ns depending on > the type of test performed. I'm suspecting that this represents 1 to 2 L1 > cache misses saved per look-up. > > One side effect of this change is that semantic_match_miss will now only > increment once per leaf instead of once per leaf_info miss. However the > stat is already skewed now that we perform a preliminary check on the leaf > as a part of the look-up. > > I also have gone through and addressed a number of ordering issues in the > first patch since I had misread the behavior of list_add_tail. > > I have since run some additional testing and verified the resulting lists > are in the same order when combining multiple prefix length and tos values > in a single leaf. Series applied, thanks Alexander.