Re: [RFC PATCH v6 00/32] perf tools: filtering events using eBPF programs
From: Wangnan (F)
Date: Tue Jun 09 2015 - 19:46:18 EST
On 2015/6/9 21:59, Arnaldo Carvalho de Melo wrote:
Em Tue, Jun 09, 2015 at 05:50:04AM +0000, Wang Nan escreveu:
This is the 6th 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
Thanks for doing this, comments below for this 00/32 file:
and
# perf record --event bpf-file.o sleep 1
This patch series is based on tip/perf/core (a3d8654).
Compared with v5 patch, this series allows user to pass BPF
scriptlet source code file directly, instead of requiring user to
pre-compile it into an ELF object. Which is done mainly by patch 24/32.
In addition, to help users setup LLVM, [bpf] perf config section is
appended. 4 command line options are also appended to 'perf record'
for setting pathes and options of clang and llc. Which is done by patch
25/32 and 32/32.
Other improvements:
1. Adjust context.
2. Get rid of 'trailing whitespace' and 'space before tab in indent'
problems.
3. Error messages are improved when BPF API checking fail.
In this series:
Patch 1/32 adds a feature check to check version of eBPF API.
Patch 2/32 - 21/32 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 22/32 - 32/32 are perf related. Patch 24, 25 and 32 are new to
support dynamical compiling.
Here is an example shows the using of dynamic compiling:
# perf record --event lock_page.c ls /
Added new event:
perf_bpf_probe:lock_page (on __lock_page)
You can now use it in all perf tools, such as:
Can we suppress these messages? They are misleading, because we will not
be able to " use it in all perf tools", since they will be removed right
after this ' perf record' session ends.
They may have value as debugging aid, so that we see what probes are
being put in place, etc, but for the default case they are just annoying
scrolling.
Sure. I don't want to alert API of add_perf_probe_events() and
__add_probe_trace_events(),
so in next version I'd like to introduce a new field in probe_conf to
control these output.
perf record -e perf_bpf_probe:lock_page -aR sleep 1
Added new event:
perf_bpf_probe:lock_page_ret (on __lock_page%return)
You can now use it in all perf tools, such as:
perf record -e perf_bpf_probe:lock_page_ret -aR sleep 1
Added new event:
perf_bpf_probe:unlock_page (on unlock_page)
You can now use it in all perf tools, such as:
perf record -e perf_bpf_probe:unlock_page -aR sleep 1
bin boot dev etc home init lib lib64 linuxrc media mnt proc root run sbin sys tmp usr var
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.002 MB perf.data ]
Removed event: perf_bpf_probe:lock_page
Removed event: perf_bpf_probe:lock_page_ret
Removed event: perf_bpf_probe:unlock_page
Ditto for this.
Where lock_page.c can be found from:
http://lkml.kernel.org/r/557025A2.6090903@xxxxxxxxxx
I'll try applying the patches and running this script, perhaps it would
be a good idea to have some /examples/ directory under som of the
tools/ directory, so that everything that is needed to test this is in
the source tree.
We need to at some point, best if right now, to make 'perf test' have an
entry for this, is this in this patchkit?
Will append. Tow parts: 1. testing llvm compiling BPF source code; 2.
loading it into kernel.
I.e. plain running 'perf test' will tell us if all this works fine, now
and everytime somebody with all the needed bits runs 'perf test'.
Thanks for the hard work!
- Arnaldo
Wang Nan (32):
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 record: Enable passing bpf object file to --event
perf record: Compile scriptlets if pass '.c' to --event
perf tools: Add 'bpf.' config section to perf default config
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 record: Add LLVM 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 | 17 +-
tools/perf/builtin-probe.c | 2 +-
tools/perf/builtin-record.c | 40 +-
tools/perf/config/Makefile | 19 +-
tools/perf/tests/make | 4 +-
tools/perf/util/Build | 1 +
tools/perf/util/bpf-loader.c | 477 ++++++++++++++++++
tools/perf/util/bpf-loader.h | 54 +++
tools/perf/util/config.c | 3 +
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/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 | 57 ++-
tools/perf/util/probe-event.h | 5 +-
32 files changed, 2229 insertions(+), 39 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/util/bpf-loader.c
create mode 100644 tools/perf/util/bpf-loader.h
--
1.8.3.4
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