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 X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 85BCAC55178 for ; Thu, 29 Oct 2020 09:34:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2423D2076B for ; Thu, 29 Oct 2020 09:34:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="jOPkRiY2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726564AbgJ2JeD (ORCPT ); Thu, 29 Oct 2020 05:34:03 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:44461 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725929AbgJ2JeC (ORCPT ); Thu, 29 Oct 2020 05:34:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1603964041; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Vt9IrI+bbNphkz41mmMtwpNk3Dc6tdCm1kauoJydoGY=; b=jOPkRiY2HUDqCriUIzumyYBdWOIQbv01gICEbAQvfQVXVwBULfD1ryyawAlilWE8opSmFq +ZlHOUZp+TPFtSqZmZWa+TBwn12gBtzsvhSR7dU19kDgO55Bevj2CRhByy/oASRoTeCJkz qbQ+/QKgcS1f/0ejlCXoxp6AxLIVLd4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-335-eWboWm2qPCWmrG4GxZMBmg-1; Thu, 29 Oct 2020 05:33:57 -0400 X-MC-Unique: eWboWm2qPCWmrG4GxZMBmg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1472364149; Thu, 29 Oct 2020 09:33:55 +0000 (UTC) Received: from krava (unknown [10.40.193.60]) by smtp.corp.redhat.com (Postfix) with SMTP id 3AEDF5B4A1; Thu, 29 Oct 2020 09:33:44 +0000 (UTC) Date: Thu, 29 Oct 2020 10:33:43 +0100 From: Jiri Olsa To: Andrii Nakryiko Cc: Jiri Olsa , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Networking , bpf , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Daniel Xu , Steven Rostedt , Jesper Brouer , Toke =?iso-8859-1?Q?H=F8iland-J=F8rgensen?= , Viktor Malik Subject: Re: [RFC bpf-next 07/16] kallsyms: Use rb tree for kallsyms name search Message-ID: <20201029093343.GB3027684@krava> References: <20201022082138.2322434-1-jolsa@kernel.org> <20201022082138.2322434-8-jolsa@kernel.org> <20201028182534.GS2900849@krava> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Oct 28, 2020 at 03:40:46PM -0700, Andrii Nakryiko wrote: > On Wed, Oct 28, 2020 at 3:29 PM Jiri Olsa wrote: > > > > On Thu, Oct 22, 2020 at 10:21:29AM +0200, Jiri Olsa wrote: > > > The kallsyms_expand_symbol function showed in several bpf related > > > profiles, because it's doing linear search. > > > > > > Before: > > > > > > Performance counter stats for './src/bpftrace -ve kfunc:__x64_sys_s* \ > > > { printf("test\n"); } i:ms:10 { printf("exit\n"); exit();}' (5 runs): > > > > > > 2,535,458,767 cycles:k ( +- 0.55% ) > > > 940,046,382 cycles:u ( +- 0.27% ) > > > > > > 33.60 +- 3.27 seconds time elapsed ( +- 9.73% ) > > > > > > Loading all the vmlinux symbols in rbtree and and switch to rbtree > > > search in kallsyms_lookup_name function to save few cycles and time. > > > > > > After: > > > > > > Performance counter stats for './src/bpftrace -ve kfunc:__x64_sys_s* \ > > > { printf("test\n"); } i:ms:10 { printf("exit\n"); exit();}' (5 runs): > > > > > > 2,199,433,771 cycles:k ( +- 0.55% ) > > > 936,105,469 cycles:u ( +- 0.37% ) > > > > > > 26.48 +- 3.57 seconds time elapsed ( +- 13.49% ) > > > > > > Each symbol takes 160 bytes, so for my .config I've got about 18 MBs > > > used for 115285 symbols. > > > > > > Signed-off-by: Jiri Olsa > > > > FYI there's init_kprobes dependency on kallsyms_lookup_name in early > > init call, so this won't work as it is :-\ will address this in v2 > > > > also I'll switch to sorted array and bsearch, because kallsyms is not > > dynamically updated > > what about kernel modules then? please check my answer to Alexei, I just answered it there thanks, jirka > > > > > jirka > > > > > --- > > > kernel/kallsyms.c | 95 ++++++++++++++++++++++++++++++++++++++++++----- > > > 1 file changed, 86 insertions(+), 9 deletions(-) > > > > > [...] >