From 56b11a2126bf2f422831ecf6112b87a4485b221b Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Fri, 11 Aug 2023 12:19:48 -0300 Subject: perf bpf: Remove support for embedding clang for compiling BPF events (-e foo.c) This never was in the default build for perf, is difficult to maintain as it uses clang/llvm internals so ditch it, keeping, for now, the external compilation of .c BPF into .o bytecode and its subsequent loading, that is also going to be removed, do it separately to help bisection and to properly document what is being removed and why. Committer notes: Extracted from a larger patch and removed some leftovers, namely deleting these now unused feature tests: tools/build/feature/test-clang.cpp tools/build/feature/test-cxx.cpp tools/build/feature/test-llvm-version.cpp tools/build/feature/test-llvm.cpp Testing the use of BPF events after applying this patch: To use the external clang/llvm toolchain to compile a .c event and then use libbpf to load it, to get the syscalls:sys_enter_open* tracepoints and read the filename pointer, putting it into the ring buffer right after the usual tracepoint payload for 'perf trace' to then print it: [root@quaco ~]# perf trace -e /home/acme/git/perf-tools-next/tools/perf/examples/bpf/augmented_raw_syscalls.c,open* --max-events=10 0.000 systemd-oomd/959 openat(dfd: CWD, filename: "/proc/meminfo", flags: RDONLY|CLOEXEC) = 12 0.083 abrt-dump-jour/1453 openat(dfd: CWD, filename: "/var/log/journal/d6a97235307247e09f13f326fb607e3c/system.journal", flags: RDONLY|CLOEXEC|NONBLOCK) = 4 0.063 abrt-dump-jour/1454 openat(dfd: CWD, filename: "/var/log/journal/d6a97235307247e09f13f326fb607e3c/system.journal", flags: RDONLY|CLOEXEC|NONBLOCK) = 4 0.082 abrt-dump-jour/1455 openat(dfd: CWD, filename: "/var/log/journal/d6a97235307247e09f13f326fb607e3c/system.journal", flags: RDONLY|CLOEXEC|NONBLOCK) = 4 250.124 systemd-oomd/959 openat(dfd: CWD, filename: "/proc/meminfo", flags: RDONLY|CLOEXEC) = 12 250.521 systemd-oomd/959 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/memory.pressure", flags: RDONLY|CLOEXEC) = 12 251.047 systemd-oomd/959 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/memory.current", flags: RDONLY|CLOEXEC) = 12 251.162 systemd-oomd/959 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/memory.min", flags: RDONLY|CLOEXEC) = 12 251.242 systemd-oomd/959 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/memory.low", flags: RDONLY|CLOEXEC) = 12 251.353 systemd-oomd/959 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/memory.swap.current", flags: RDONLY|CLOEXEC) = 12 [root@quaco ~]# Same thing, but with a prebuilt .o BPF bytecode: [root@quaco ~]# perf trace -e /home/acme/git/perf-tools-next/tools/perf/examples/bpf/augmented_raw_syscalls.o,open* --max-events=10 0.000 systemd-oomd/959 openat(dfd: CWD, filename: "/proc/meminfo", flags: RDONLY|CLOEXEC) = 12 0.083 abrt-dump-jour/1453 openat(dfd: CWD, filename: "/var/log/journal/d6a97235307247e09f13f326fb607e3c/system.journal", flags: RDONLY|CLOEXEC|NONBLOCK) = 4 0.083 abrt-dump-jour/1455 openat(dfd: CWD, filename: "/var/log/journal/d6a97235307247e09f13f326fb607e3c/system.journal", flags: RDONLY|CLOEXEC|NONBLOCK) = 4 0.062 abrt-dump-jour/1454 openat(dfd: CWD, filename: "/var/log/journal/d6a97235307247e09f13f326fb607e3c/system.journal", flags: RDONLY|CLOEXEC|NONBLOCK) = 4 249.985 systemd-oomd/959 openat(dfd: CWD, filename: "/proc/meminfo", flags: RDONLY|CLOEXEC) = 12 466.763 thermald/1234 openat(dfd: CWD, filename: "/sys/class/powercap/intel-rapl/intel-rapl:0/intel-rapl:0:2/energy_uj") = 13 467.145 thermald/1234 openat(dfd: CWD, filename: "/sys/class/powercap/intel-rapl/intel-rapl:0/energy_uj") = 13 467.311 thermald/1234 openat(dfd: CWD, filename: "/sys/class/thermal/thermal_zone2/temp") = 13 500.040 cgroupify/24006 openat(dfd: 4, filename: ".", flags: RDONLY|CLOEXEC|DIRECTORY|NONBLOCK) = 5 500.295 cgroupify/24006 openat(dfd: 4, filename: "24616/cgroup.procs") = 5 [root@quaco ~]# Signed-off-by: Ian Rogers Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Andrii Nakryiko Cc: Anshuman Khandual Cc: Athira Rajeev Cc: Brendan Gregg Cc: Carsten Haitzler Cc: Eduard Zingerman Cc: Fangrui Song Cc: He Kuang Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Leo Yan Cc: Madhavan Srinivasan Cc: Mark Rutland Cc: Namhyung Kim Cc: Nathan Chancellor Cc: "Naveen N. Rao" Cc: Nick Desaulniers Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Rob Herring Cc: Tiezhu Yang Cc: Tom Rix Cc: Wang Nan Cc: Wang ShaoBo Cc: Yang Jihong Cc: Yonghong Song Cc: YueHaibing Link: https://lore.kernel.org/lkml/ZNZWsAXg2px1sm2h@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/c++/clang-test.cpp | 67 -------------------------------------- 1 file changed, 67 deletions(-) delete mode 100644 tools/perf/util/c++/clang-test.cpp (limited to 'tools/perf/util/c++/clang-test.cpp') diff --git a/tools/perf/util/c++/clang-test.cpp b/tools/perf/util/c++/clang-test.cpp deleted file mode 100644 index a4683ca53697..000000000000 --- a/tools/perf/util/c++/clang-test.cpp +++ /dev/null @@ -1,67 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -#include "clang.h" -#include "clang-c.h" -extern "C" { -#include "../util.h" -} -#include "llvm/IR/Function.h" -#include "llvm/IR/LLVMContext.h" - -#include -#include - -class perf_clang_scope { -public: - explicit perf_clang_scope() {perf_clang__init();} - ~perf_clang_scope() {perf_clang__cleanup();} -}; - -static std::unique_ptr -__test__clang_to_IR(void) -{ - unsigned int kernel_version; - - if (fetch_kernel_version(&kernel_version, NULL, 0)) - return std::unique_ptr(nullptr); - - std::string cflag_kver("-DLINUX_VERSION_CODE=" + - std::to_string(kernel_version)); - - std::unique_ptr M = - perf::getModuleFromSource({cflag_kver.c_str()}, - "perf-test.c", - test_llvm__bpf_base_prog); - return M; -} - -extern "C" { -int test__clang_to_IR(struct test_suite *test __maybe_unused, - int subtest __maybe_unused) -{ - perf_clang_scope _scope; - - auto M = __test__clang_to_IR(); - if (!M) - return -1; - for (llvm::Function& F : *M) - if (F.getName() == "bpf_func__SyS_epoll_pwait") - return 0; - return -1; -} - -int test__clang_to_obj(struct test_suite *test __maybe_unused, - int subtest __maybe_unused) -{ - perf_clang_scope _scope; - - auto M = __test__clang_to_IR(); - if (!M) - return -1; - - auto Buffer = perf::getBPFObjectFromModule(&*M); - if (!Buffer) - return -1; - return 0; -} - -} -- cgit