[RFC PATCH v7 00/37] perf tools: filtering events using eBPF programs

Wang Nan
2015-06-12T05:40:23Z

This is the 7th version which tries to introduce eBPF programs to perf.
It enables 'perf record' to filter events using eBPF programs like:

# perf record --event bpf-file.c sleep 1

and

# perf record --event bpf-file.o sleep 1

This patch series is based on tip/perf/core (028c63b).

Compare with v6 patch, this series totally refactor code for llvm
compiling '.c' into BPF object file using LLVM. Including:

1. A specific file tools/perf/util/llvm-utils.c is introduced for
holding all llvm/clang related work, instead of putting them into
bpf-loader.c.

2. Automatically detect kernel include options by embedded shell
script.

3. Use command line template to generate compiler commands instead of
assemble cmdline with printf, passing variables using environment.
Which enable users to define their own compiler commands.

4. Introduce '[llvm]' section to perf default config.
5 options can be configured, but all of them can be omitted:

[llvm]
# Path to clang. If omit, search it from $PATH.
clang-path = "/path/to/clang"

# Cmdline template. Following line shows its default value.
# Environment variable is used to passing options.
clang-bpf-cmd-template = "$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS -Wno-unused-value -Wno-pointer-sign -working-directory $WORKING_DIR -c $CLANG_SOURCE -target bpf -O2 -o -"

# Option passed to clang, will be passed to cmdline by $CLANG_OPTIONS.
clang-opt = "-Wno-unused-value -Wno-pointer-sign"

# kbuild directory. If not set, use /lib/modules/`uname -r`/build.
# If set to "" deliberately, skip kernel header auto-detector.
kbuild-dir = "/path/to/kernel/build"

# Options passed to 'make' when detecting kernel header options.
kbuild-opts = "ARCH=x86_64"

Command line options '--clang-path' and '--clang-opt' is appended to
'perf record'.

5. LLVM and BPF opening testcase is adding into 'perf test':

# perf test 37
37: Test LLVM searching and compiling : Ok

6. Warning and error messages improvement.

7. Issue clang command suit for newest clang which support
'-target bpf', instead of calling
'clang -emit-llvm | llc -march=bpf' pipe.

Other improvements including:

1. Add ../lib/bpf into TAG_FOLDERS in tools/perf/Makefile.perf.
2. Fix dependency problem: when NO_LIBBPF=1 is set don't compile
libbpf.
3. Suppress misleading messages printed during probing.
4. In perf record, when bpf__probe failed, goto out_symbol_exit instead
of directly return.

In this series:
Patch 1/37 adds a feature check to check version of eBPF API.

Patch 2/37 - 21/37 introduce libbpf, which first parse eBPF object
files then load maps and programs into kernel. These patches are
already received 'Acked-by' from Alexei Starovoitov except patch
5/32, which enables opening a memory-based object file image using
bpf_object__open_buffer().

Patch 22/37 - 37/37 are perf related. Patch 23/37 - 27/37 are
llvm-utils, which does most of new stuffs in this series.
Patch 29/37 use functions defined previously to dynamically
compile scriptlets.

Patch 36/37 suppresses misleading messages printed during probing.

Patch 37/37 adds new options to 'perf record'.

Wang Nan (37):
tools build: Add feature check for eBPF API
bpf tools: Introduce 'bpf' library to tools
bpf tools: Allow caller to set printing function
bpf tools: Open eBPF object file and do basic validation
bpf tools: Read eBPF object from buffer
bpf tools: Check endianess and make libbpf fail early
bpf tools: Iterate over ELF sections to collect information
bpf tools: Collect version and license from ELF sections
bpf tools: Collect map definitions from 'maps' section
bpf tools: Collect symbol table from SHT_SYMTAB section
bpf tools: Collect eBPF programs from their own sections
bpf tools: Collect relocation sections from SHT_REL sections
bpf tools: Record map accessing instructions for each program
bpf tools: Add bpf.c/h for common bpf operations
bpf tools: Create eBPF maps defined in an object file
bpf tools: Relocate eBPF programs
bpf tools: Introduce bpf_load_program() to bpf.c
bpf tools: Load eBPF programs in object files into kernel
bpf tools: Introduce accessors for struct bpf_program
bpf tools: Introduce accessors for struct bpf_object
bpf tools: Link all bpf objects onto a list
perf tools: Make perf depend on libbpf
perf tools: Introduce llvm config options
perf tools: Call clang to compile C source to object code
perf tests: Add LLVM test for eBPF on-the-fly compiling
perf tools: Auto detecting kernel build directory
perf tools: Auto detecting kernel include options
perf record: Enable passing bpf object file to --event
perf record: Compile scriptlets if pass '.c' to --event
perf tools: Parse probe points of eBPF programs during preparation
perf probe: Attach trace_probe_event with perf_probe_event
perf record: Probe at kprobe points
perf record: Load all eBPF object into kernel
perf tools: Add bpf_fd field to evsel and config it
perf tools: Attach eBPF program to perf event
perf tools: Suppress probing messages when probing by BPF loading
perf record: Add clang options for compiling BPF scripts

tools/build/Makefile.feature | 6 +-
tools/build/feature/Makefile | 6 +-
tools/build/feature/test-bpf.c | 18 +
tools/lib/bpf/.gitignore | 2 +
tools/lib/bpf/Build | 1 +
tools/lib/bpf/Makefile | 195 ++++++++
tools/lib/bpf/bpf.c | 84 ++++
tools/lib/bpf/bpf.h | 23 +
tools/lib/bpf/libbpf.c | 1037 +++++++++++++++++++++++++++++++++++++++
tools/lib/bpf/libbpf.h | 85 ++++
tools/perf/MANIFEST | 3 +
tools/perf/Makefile.perf | 19 +-
tools/perf/builtin-probe.c | 2 +-
tools/perf/builtin-record.c | 43 +-
tools/perf/config/Makefile | 19 +-
tools/perf/tests/Build | 1 +
tools/perf/tests/builtin-test.c | 4 +
tools/perf/tests/llvm.c | 85 ++++
tools/perf/tests/make | 4 +-
tools/perf/tests/tests.h | 1 +
tools/perf/util/Build | 2 +
tools/perf/util/bpf-loader.c | 302 ++++++++++++
tools/perf/util/bpf-loader.h | 46 ++
tools/perf/util/config.c | 4 +
tools/perf/util/debug.c | 5 +
tools/perf/util/debug.h | 1 +
tools/perf/util/evlist.c | 51 ++
tools/perf/util/evlist.h | 1 +
tools/perf/util/evsel.c | 17 +
tools/perf/util/evsel.h | 1 +
tools/perf/util/llvm-utils.c | 370 ++++++++++++++
tools/perf/util/llvm-utils.h | 39 ++
tools/perf/util/parse-events.c | 16 +
tools/perf/util/parse-events.h | 2 +
tools/perf/util/parse-events.l | 6 +
tools/perf/util/parse-events.y | 29 +-
tools/perf/util/probe-event.c | 76 +--
tools/perf/util/probe-event.h | 6 +-
38 files changed, 2567 insertions(+), 45 deletions(-)
create mode 100644 tools/build/feature/test-bpf.c
create mode 100644 tools/lib/bpf/.gitignore
create mode 100644 tools/lib/bpf/Build
create mode 100644 tools/lib/bpf/Makefile
create mode 100644 tools/lib/bpf/bpf.c
create mode 100644 tools/lib/bpf/bpf.h
create mode 100644 tools/lib/bpf/libbpf.c
create mode 100644 tools/lib/bpf/libbpf.h
create mode 100644 tools/perf/tests/llvm.c
create mode 100644 tools/perf/util/bpf-loader.c
create mode 100644 tools/perf/util/bpf-loader.h
create mode 100644 tools/perf/util/llvm-utils.c
create mode 100644 tools/perf/util/llvm-utils.h

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1.8.3.4