From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 78919CCA47C for ; Thu, 23 Jun 2022 18:08:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233882AbiFWSIt (ORCPT ); Thu, 23 Jun 2022 14:08:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47626 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236665AbiFWSIO (ORCPT ); Thu, 23 Jun 2022 14:08:14 -0400 Received: from mail.netfilter.org (mail.netfilter.org [217.70.188.207]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 2727CBB01D for ; Thu, 23 Jun 2022 10:19:41 -0700 (PDT) Date: Thu, 23 Jun 2022 19:19:36 +0200 From: Pablo Neira Ayuso To: Phil Sutter , netfilter-devel@vger.kernel.org Subject: Re: [PATCH nft 2/2,v2] intervals: Do not sort cached set elements over and over again Message-ID: References: <20220616090446.275985-1-pablo@netfilter.org> <20220616090446.275985-2-pablo@netfilter.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org On Thu, Jun 23, 2022 at 06:25:35PM +0200, Phil Sutter wrote: > On Thu, Jun 23, 2022 at 06:17:16PM +0200, Pablo Neira Ayuso wrote: > > On Thu, Jun 23, 2022 at 06:05:20PM +0200, Phil Sutter wrote: > > > On Thu, Jun 16, 2022 at 11:04:46AM +0200, Pablo Neira Ayuso wrote: > > > > From: Phil Sutter > > > > > > > > When adding element(s) to a non-empty set, code merged the two lists and > > > > sorted the result. With many individual 'add element' commands this > > > > causes substantial overhead. Make use of the fact that > > > > existing_set->init is sorted already, sort only the list of new elements > > > > and use list_splice_sorted() to merge the two sorted lists. > > > > > > > > Add set_sort_splice() and use it for set element overlap detection and > > > > automerge. > > > > > > > > A test case adding ~25k elements in individual commands completes in > > > > about 1/4th of the time with this patch applied. > > > > > > > > Joint work with Pablo. > > > > > > > > Fixes: 3da9643fb9ff9 ("intervals: add support to automerge with kernel elements") > > > > Signed-off-by: Phil Sutter > > > > Signed-off-by: Pablo Neira Ayuso > > > > > > Thanks for picking it up, I missed the automerge code being very > > > similar. > > > > > > I worked on a patch to move the whole set adjustment to a separate step > > > after evaluating commands, but it's a bit larger effort as it requires > > > to combine overlap detection, auto merge and element deletion. With > > > simple appending new elements in eval phase and reacting upon > > > EXPR_F_KERNEL and EXPR_F_REMOVE flags, I guess it's possible to update > > > the whole set in one go. > > > > You mean, appending if they come in order as in your test ruleset? Not > > sure what you are suggesting. > > It was merely loud thinking - combining repeated 'add element' commands > is fine with me for avoiding the problem. I have an alternative in mind > where added elements are appended to the set without EXPR_F_KERNEL and > removed ones also with EXPR_F_REMOVE. So after nft_evaluate() one could > do all the overlap detection / auto merging / element removing once for > each changed set. I have pushed out this coalesce approach to tackle this regression. Feel free to revisit this approach.