From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 150622746A; Fri, 6 Jun 2025 19:04:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749236695; cv=none; b=UpUiuIdTmyaBW/mkFQYQ1GJoS0ip4lehoTFund7SqJwxuTpIXVUDQZt3wmak+S6eGgThzwoXnmeuT12stuU7JB+Ij+zSSz02oRWkOn2UreX//GkOohnW1fZHJfBVh59aAphyMJZeKX1fH5+nMPLrppSPErp9/B0scjfaPvM/FUk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749236695; c=relaxed/simple; bh=fuYqdoV1jvKU3tUKFTnTsNAh6QOQSVphydcsDKTi/LQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=gO9yUxRk5KJ4w0l5LlMQqZSnfEscjsVflHIfKN5d3Yrh62cEHlSeoJnaNzM3/T2MSwOxKQO4TjqZ7iO58ctcBsG6+lzscImPnLHvVZECXvC5k3GvcHrm6Zvq5dnTeNRNvuXxUeRCib+4Z28xI+9WeXmL0Ia1zB3iZIW7jf24ex8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GIjkbpRy; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GIjkbpRy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 87DD0C4CEEB; Fri, 6 Jun 2025 19:04:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1749236694; bh=fuYqdoV1jvKU3tUKFTnTsNAh6QOQSVphydcsDKTi/LQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=GIjkbpRyH44Mlt7GAnAgaOAIRy4YqXVlLPyuoVWVvX6QHHsLAwoMb+ZYgdpLWu/RD mplKgMnNVeZrWGOyXae6f34CJGx03x4xZDU4+b6+62FMvLAW6Y9PYF+TR780QTFmpu ElB1/EOBJpmqs0nPQYHs3mJ/BlteV9moMfLKVQ5ivTWSj4aaundU3qGIgpMce2FiLK VtBCar1apDUTvlccIvzLiW6c//Peg8571g/tinuHpTtBB6P0ryRkKFjjMdzoQ2tmPL tWuzbm5GdhoqEpfT/Uz+M+hAxpYMG7yhXghzjF2i+eaFWiMJ9SlPBPEbHMMqwFk9QP tiNyMi/Q+54Dg== Date: Fri, 6 Jun 2025 12:04:52 -0700 From: Namhyung Kim To: Blake Jones Cc: Arnaldo Carvalho de Melo , Ian Rogers , Jiri Olsa , Peter Zijlstra , Ingo Molnar , Mark Rutland , Alexander Shishkin , Adrian Hunter , Kan Liang , Steven Rostedt , Tomas Glozar , James Clark , Leo Yan , Guilherme Amadio , Yang Jihong , Charlie Jenkins , Chun-Tse Shao , Aditya Gupta , Athira Rajeev , Zhongqiu Han , Andi Kleen , Dmitry Vyukov , Yujie Liu , Graham Woodward , Yicong Yang , Ben Gainey , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, bpf@vger.kernel.org Subject: Re: [PATCH v2 1/4] perf: detect support for libbpf's emit_strings option Message-ID: References: <20250605233934.1881839-1-blakejones@google.com> <20250605233934.1881839-2-blakejones@google.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250605233934.1881839-2-blakejones@google.com> On Thu, Jun 05, 2025 at 04:39:31PM -0700, Blake Jones wrote: > This creates a config option that detects libbpf's ability to display > character arrays as strings, which was just added to the BPF tree > (https://git.kernel.org/bpf/bpf-next/c/87c9c79a02b4). > > To test this change, I built perf (from later in this patch set) with: > > - static libbpf (default, using source from kernel tree) > - dynamic libbpf (LIBBPF_DYNAMIC=1 LIBBPF_INCLUDE=/usr/local/include) > > For both the static and dynamic versions, I used headers with and without > the ".emit_strings" option. > > I verified that of the four resulting binaries, the two with > ".emit_strings" would successfully record BPF_METADATA events, and the two > without wouldn't. All four binaries would successfully display > BPF_METADATA events, because the relevant bit of libbpf code is only used > during "perf record". > > Signed-off-by: Blake Jones > --- > tools/build/Makefile.feature | 1 + > tools/build/feature/Makefile | 4 ++++ > tools/build/feature/test-libbpf-strings.c | 10 ++++++++++ > tools/perf/Documentation/perf-check.txt | 1 + > tools/perf/Makefile.config | 12 ++++++++++++ > tools/perf/builtin-check.c | 1 + > 6 files changed, 29 insertions(+) > create mode 100644 tools/build/feature/test-libbpf-strings.c > > diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature > index 57bd995ce6af..541ea3cc53e9 100644 > --- a/tools/build/Makefile.feature > +++ b/tools/build/Makefile.feature > @@ -126,6 +126,7 @@ FEATURE_TESTS_EXTRA := \ > llvm \ > clang \ > libbpf \ > + libbpf-strings \ > libbpf-btf__load_from_kernel_by_id \ > libbpf-bpf_prog_load \ > libbpf-bpf_object__next_program \ Please check out tmp.perf-tools-next branch which made some changes in the area. Thanks, Namhyung > diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile > index b8b5fb183dd4..327bb501fd2b 100644 > --- a/tools/build/feature/Makefile > +++ b/tools/build/feature/Makefile > @@ -59,6 +59,7 @@ FILES= \ > test-lzma.bin \ > test-bpf.bin \ > test-libbpf.bin \ > + test-libbpf-strings.bin \ > test-get_cpuid.bin \ > test-sdt.bin \ > test-cxx.bin \ > @@ -360,6 +361,9 @@ $(OUTPUT)test-libbpf-bpf_program__set_insns.bin: > $(OUTPUT)test-libbpf-btf__raw_data.bin: > $(BUILD) -lbpf > > +$(OUTPUT)test-libbpf-strings.bin: > + $(BUILD) > + > $(OUTPUT)test-sdt.bin: > $(BUILD) > > diff --git a/tools/build/feature/test-libbpf-strings.c b/tools/build/feature/test-libbpf-strings.c > new file mode 100644 > index 000000000000..83e6c45f5c85 > --- /dev/null > +++ b/tools/build/feature/test-libbpf-strings.c > @@ -0,0 +1,10 @@ > +// SPDX-License-Identifier: GPL-2.0 > +#include > + > +int main(void) > +{ > + struct btf_dump_type_data_opts opts; > + > + opts.emit_strings = 0; > + return opts.emit_strings; > +} > diff --git a/tools/perf/Documentation/perf-check.txt b/tools/perf/Documentation/perf-check.txt > index a764a4629220..799982d8d868 100644 > --- a/tools/perf/Documentation/perf-check.txt > +++ b/tools/perf/Documentation/perf-check.txt > @@ -52,6 +52,7 @@ feature:: > dwarf-unwind / HAVE_DWARF_UNWIND_SUPPORT > auxtrace / HAVE_AUXTRACE_SUPPORT > libbfd / HAVE_LIBBFD_SUPPORT > + libbpf-strings / HAVE_LIBBPF_STRINGS_SUPPORT > libcapstone / HAVE_LIBCAPSTONE_SUPPORT > libcrypto / HAVE_LIBCRYPTO_SUPPORT > libdw-dwarf-unwind / HAVE_LIBDW_SUPPORT > diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config > index d1ea7bf44964..647ade45e4e5 100644 > --- a/tools/perf/Makefile.config > +++ b/tools/perf/Makefile.config > @@ -595,8 +595,20 @@ ifndef NO_LIBELF > LIBBPF_STATIC := 1 > $(call detected,CONFIG_LIBBPF) > CFLAGS += -DHAVE_LIBBPF_SUPPORT > + ifneq ($(OUTPUT),) > + LIBBPF_INCLUDE = $(abspath $(OUTPUT))/libbpf/include > + else > + LIBBPF_INCLUDE = $(CURDIR)/libbpf/include > + endif > endif > endif > + > + FEATURE_CHECK_CFLAGS-libbpf-strings="-I$(LIBBPF_INCLUDE)" > + $(call feature_check,libbpf-strings) > + ifeq ($(feature-libbpf-strings), 1) > + $(call detected,CONFIG_LIBBPF_STRINGS) > + CFLAGS += -DHAVE_LIBBPF_STRINGS_SUPPORT > + endif > endif > endif # NO_LIBBPF > endif # NO_LIBELF > diff --git a/tools/perf/builtin-check.c b/tools/perf/builtin-check.c > index 9a509cb3bb9a..f4827f0ddb47 100644 > --- a/tools/perf/builtin-check.c > +++ b/tools/perf/builtin-check.c > @@ -43,6 +43,7 @@ struct feature_status supported_features[] = { > FEATURE_STATUS("dwarf-unwind", HAVE_DWARF_UNWIND_SUPPORT), > FEATURE_STATUS("auxtrace", HAVE_AUXTRACE_SUPPORT), > FEATURE_STATUS_TIP("libbfd", HAVE_LIBBFD_SUPPORT, "Deprecated, license incompatibility, use BUILD_NONDISTRO=1 and install binutils-dev[el]"), > + FEATURE_STATUS("libbpf-strings", HAVE_LIBBPF_STRINGS_SUPPORT), > FEATURE_STATUS("libcapstone", HAVE_LIBCAPSTONE_SUPPORT), > FEATURE_STATUS("libcrypto", HAVE_LIBCRYPTO_SUPPORT), > FEATURE_STATUS("libdw-dwarf-unwind", HAVE_LIBDW_SUPPORT), > -- > 2.50.0.rc0.604.gd4ff7b7c86-goog >