[RFC PATCH v8 00/49] perf tools: filtering events using eBPF programs

From: Wang Nan
Date: Wed Jun 24 2015 - 08:33:19 EST

This is the 8th version which tries to introduce eBPF programs to perf.

Since version 7 is still being reviewed, this series keeps patch 1/49
to 37/49 identical to what they are in v7 except a small modification
in patch 36/48, which prints more debug information when silent is set,
and some context to rebase them onto newest tip/perf/core (a9a3cd9).

The core stuffs in this series resides in 38/49 - 49/49, which allow
users to access kernel data through parameters of eBPF programs. Now
it is possible to write eBPF programs like this:

SEC("get_superblock=journal_get_superblock journal->j_errno")
int get_superblock(struct pt_regs *ctx, int err, int j_errno)
{
char fmt[] = "j_errno=%lx\n";
bpf_trace_printk(fmt, sizeof(fmt), j_errno);
if (j_errno)
return 1;
return 0;
}

Where, 'j_errno' in that function will be dereferenced according to
dwarf information by prologue generated by perf. 'err' indicates the
successfulness of the dereferencing.

He Kuang posted 2 series on that idea it a month ago:

http://lkml.kernel.org/r/1432456091-73384-1-git-send-email-hekuang@xxxxxxxxxx

This series totally rewrite its code, the interface is also changed.

In addition, this series of patches supports setting BPF program to
multiple probing points and generate different prologue for all of them
if necessary. Using glob matching is also allowed. In the above
example, there will be two journal_get_superblock() functions in kernel
if we compile both jbd and jbd2. That BPF function tracks both of them.

In this series:
Patch 01/49 - 37/49 are identical to v7 series, except context
adjustments and a small improvement in 36/49.

Patch 38/49 - 43/49 are preparation. Where 39/49 gives libbpf the
ability to load multiple instances. New interfaces
are introduced for it.

Patch 44/49 - 47/49 introduce bpf-prologue.c into perf, whcih generates
prologue according to argument list of pevs. Core
functions are in 46/49. Its commit message
describes the detail of prologue generation.

Patch 48/49 groups similar prologue together and only create one BPF
program instance for events which can share prologue.

Patch 49/49 adds '--vmlinux' to 'perf record' to allow it access dwarf
information.

He Kuang (4):
perf tools: Move linux/filter.h to tools/include
perf tools: Introduce arch_get_reg_info() for x86
perf tools: Add prologue for BPF programs for fetching arguments
perf record: Support custom vmlinux path

Wang Nan (45):
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
bpf tools: Load instructions buffer using load_program()
bpf tools: Load a program with different instance using preprocessor
perf tools: Fix probe-event.h include
perf probe: Reset tev->args and tev->nargs when failure
perf tools: Iterater over tev instead of pev in bpf__for_each_program
perf tools: Add BPF_PROLOGUE config options for further patches
perf tools: Generate prologue for BPF programs
perf tools: Use same BPF program if arguments are identical

tools/build/Makefile.feature | 6 +-
tools/build/feature/Makefile | 6 +-
tools/build/feature/test-bpf.c | 18 +
tools/include/linux/filter.h | 237 +++++++
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 | 1173 +++++++++++++++++++++++++++++++++
tools/lib/bpf/libbpf.h | 107 +++
tools/perf/MANIFEST | 4 +
tools/perf/Makefile.perf | 19 +-
tools/perf/arch/x86/Makefile | 1 +
tools/perf/arch/x86/util/Build | 2 +
tools/perf/arch/x86/util/dwarf-regs.c | 104 ++-
tools/perf/builtin-probe.c | 2 +-
tools/perf/builtin-record.c | 47 +-
tools/perf/config/Makefile | 31 +-
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 | 3 +
tools/perf/util/bpf-loader.c | 556 ++++++++++++++++
tools/perf/util/bpf-loader.h | 46 ++
tools/perf/util/bpf-prologue.c | 425 ++++++++++++
tools/perf/util/bpf-prologue.h | 19 +
tools/perf/util/config.c | 4 +
tools/perf/util/debug.c | 5 +
tools/perf/util/debug.h | 1 +
tools/perf/util/evlist.c | 41 ++
tools/perf/util/evlist.h | 1 +
tools/perf/util/evsel.c | 17 +
tools/perf/util/evsel.h | 1 +
tools/perf/util/include/dwarf-regs.h | 7 +
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 | 81 ++-
tools/perf/util/probe-event.h | 7 +-
tools/perf/util/probe-finder.c | 4 +
46 files changed, 3761 insertions(+), 76 deletions(-)
create mode 100644 tools/build/feature/test-bpf.c
create mode 100644 tools/include/linux/filter.h
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/bpf-prologue.c
create mode 100644 tools/perf/util/bpf-prologue.h
create mode 100644 tools/perf/util/llvm-utils.c
create mode 100644 tools/perf/util/llvm-utils.h

--
1.8.3.4

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