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=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 D4C4EC55ABD for ; Mon, 16 Nov 2020 19:16:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B1D622263 for ; Mon, 16 Nov 2020 19:16:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="ny/CgSxS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728990AbgKPTPs (ORCPT ); Mon, 16 Nov 2020 14:15:48 -0500 Received: from mail.kernel.org ([198.145.29.99]:57194 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728923AbgKPTPs (ORCPT ); Mon, 16 Nov 2020 14:15:48 -0500 Received: from quaco.ghostprotocols.net (unknown [179.97.37.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0D9942225B; Mon, 16 Nov 2020 19:15:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605554147; bh=NJspIPyHbhGJHM9+8unhyJLFO+kXAoaHYACkRxRivns=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ny/CgSxSA/pEVuvIDnh4DpYWwwXPPQMx/oTynUzL+aJRGQkhVeMwrk9cQ4PiUATI/ qiBu6y2iqE8iMAyx219M1Y21AyQPc447BTwIFH6vygn/28hFoGnXnNWeQ24tK7XiZ/ EBJgSwHyDCQArLYTTPZGqktt3JYCdrccGfzZnCnA= Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id C82C440E29; Mon, 16 Nov 2020 16:15:44 -0300 (-03) Date: Mon, 16 Nov 2020 16:15:44 -0300 From: Arnaldo Carvalho de Melo To: Jiri Olsa Cc: Andrii Nakryiko , Jiri Olsa , dwarves@vger.kernel.org, bpf , Alexei Starovoitov , Andrii Nakryiko , Yonghong Song , Hao Luo Subject: Re: [PATCH 2/2] btf_encoder: Fix function generation Message-ID: <20201116191544.GA614220@kernel.org> References: <20201113151222.852011-1-jolsa@kernel.org> <20201113151222.852011-3-jolsa@kernel.org> <20201113212907.GD842058@krava> <20201116135016.GA509215@kernel.org> <20201116182145.GF1081385@krava> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201116182145.GF1081385@krava> X-Url: http://acmel.wordpress.com Precedence: bulk List-ID: X-Mailing-List: dwarves@vger.kernel.org Em Mon, Nov 16, 2020 at 07:21:45PM +0100, Jiri Olsa escreveu: > On Mon, Nov 16, 2020 at 10:50:16AM -0300, Arnaldo Carvalho de Melo wrote: > > Em Fri, Nov 13, 2020 at 01:43:47PM -0800, Andrii Nakryiko escreveu: > > > On Fri, Nov 13, 2020 at 1:29 PM Jiri Olsa wrote: > > > > > > On Fri, Nov 13, 2020 at 12:56:40PM -0800, Andrii Nakryiko wrote: > > > > > On Fri, Nov 13, 2020 at 7:13 AM Jiri Olsa wrote: > > > > > > > > Current conditions for picking up function records break > > > > > > BTF data on some gcc versions. > > > > > > > > Some function records can appear with no arguments but with > > > > > > declaration tag set, so moving the 'fn->declaration' in front > > > > > > of other checks. > > > > > > > > Then checking if argument names are present and finally checking > > > > > > ftrace filter if it's present. If ftrace filter is not available, > > > > > > using the external tag to filter out non external functions. > > > > > > > > Signed-off-by: Jiri Olsa > > > > > > > I tested locally, all seems to work fine. Left few suggestions below, > > > > > but those could be done in follow ups (or argued to not be done). > > > > > > > Acked-by: Andrii Nakryiko > > > > > > > BTW, for some stats. > > > > > > > BEFORE allowing static funcs: > > > > > > Nowhere in the last patchkit comments is some explanation for the > > inclusion of static functions :-\ After the first patch in the last > > series I get: > > > > $ llvm-objcopy --remove-section=.BTF vmlinux > > $ readelf -SW vmlinux | grep BTF > > $ pahole -J vmlinux > > $ bpftool btf dump file ./vmlinux | grep 'FUNC '| cut -d\' -f2 | sort > before.bpftool > > $ cp vmlinux vmlinux.before.all > > $ wc -l before.bpftool > > 28829 before.bpftool > > I think you see the original number of functions, because without > the 'not merged' kernel patch, that added the special init section, > pahole will fail to detect vmlinux and fall back to checking dwarf > declarations Indeed, I moved the verbose/force setting to the beggining of the encoder and: ------------ Found 352 per-CPU variables! vmlinux not detected, falling back to dwarf data File vmlinux: search cu '/home/acme/git/linux/arch/x86/kernel/head_64.S' for percpu global variables. ----------------- Now I have to read that code to figure out what that "vmlinux not detected, falling back to dwarf data" message means, as vmlinux is where DWARF data is, so what is that isn't being "detected", /me checks... - Arnaldo > there's a verbose message for the fall back, but it is not displayed > at the moment ;-) with the fix below you should see it: > > $ LLVM_OBJCOPY=objcopy ./pahole -V -J vmlinux >out > $ cat out | grep 'vmlinux not detected' > vmlinux not detected, falling back to dwarf data > > I'll check on the verbose setup and send full patch, > I did not expect it would not get printed, sry > > so the new numebr ~41k functions is together static functions > and init functions > > jirka > > > --- > diff --git a/btf_encoder.c b/btf_encoder.c > index 9b93e9963727..7efd26de5815 100644 > --- a/btf_encoder.c > +++ b/btf_encoder.c > @@ -584,6 +584,8 @@ int cu__encode_btf(struct cu *cu, int verbose, bool force, > struct tag *pos; > int err = 0; > > + btf_elf__verbose = verbose; > + > if (btfe && strcmp(btfe->filename, cu->filename)) { > err = btf_encoder__encode(); > if (err) > @@ -623,7 +625,6 @@ int cu__encode_btf(struct cu *cu, int verbose, bool force, > } > } > > - btf_elf__verbose = verbose; > btf_elf__force = force; > type_id_off = btf__get_nr_types(btfe->btf); > > diff --git a/lib/bpf b/lib/bpf > --- a/lib/bpf > +++ b/lib/bpf > @@ -1 +1 @@ > -Subproject commit ff797cc905d9c5fe9acab92d2da127342b20f80f > +Subproject commit ff797cc905d9c5fe9acab92d2da127342b20f80f-dirty > -- - Arnaldo