diff options
author | Song Liu <songliubraving@fb.com> | 2020-03-09 20:32:15 +0300 |
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committer | Daniel Borkmann <daniel@iogearbox.net> | 2020-03-10 02:04:07 +0300 |
commit | 47c09d6a9f6794caface4ad50930460b82d7c670 (patch) | |
tree | bc29e8f83ffc3df13df0650e19c884970a6ab406 /tools/bpf/bpftool/skeleton/profiler.h | |
parent | 7b4b73bc8a609fa9655022ed24a7a714bc8c2155 (diff) |
bpftool: Introduce "prog profile" command
With fentry/fexit programs, it is possible to profile BPF program with
hardware counters. Introduce bpftool "prog profile", which measures key
metrics of a BPF program.
bpftool prog profile command creates per-cpu perf events. Then it attaches
fentry/fexit programs to the target BPF program. The fentry program saves
perf event value to a map. The fexit program reads the perf event again,
and calculates the difference, which is the instructions/cycles used by
the target program.
Example input and output:
./bpftool prog profile id 337 duration 3 cycles instructions llc_misses
4228 run_cnt
3403698 cycles (84.08%)
3525294 instructions # 1.04 insn per cycle (84.05%)
13 llc_misses # 3.69 LLC misses per million isns (83.50%)
This command measures cycles and instructions for BPF program with id
337 for 3 seconds. The program has triggered 4228 times. The rest of the
output is similar to perf-stat. In this example, the counters were only
counting ~84% of the time because of time multiplexing of perf counters.
Note that, this approach measures cycles and instructions in very small
increments. So the fentry/fexit programs introduce noticeable errors to
the measurement results.
The fentry/fexit programs are generated with BPF skeletons. Therefore, we
build bpftool twice. The first time _bpftool is built without skeletons.
Then, _bpftool is used to generate the skeletons. The second time, bpftool
is built with skeletons.
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200309173218.2739965-2-songliubraving@fb.com
Diffstat (limited to 'tools/bpf/bpftool/skeleton/profiler.h')
-rw-r--r-- | tools/bpf/bpftool/skeleton/profiler.h | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/tools/bpf/bpftool/skeleton/profiler.h b/tools/bpf/bpftool/skeleton/profiler.h new file mode 100644 index 000000000000..e03b53eae767 --- /dev/null +++ b/tools/bpf/bpftool/skeleton/profiler.h @@ -0,0 +1,47 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ +#ifndef __PROFILER_H +#define __PROFILER_H + +/* useful typedefs from vmlinux.h */ + +typedef signed char __s8; +typedef unsigned char __u8; +typedef short int __s16; +typedef short unsigned int __u16; +typedef int __s32; +typedef unsigned int __u32; +typedef long long int __s64; +typedef long long unsigned int __u64; + +typedef __s8 s8; +typedef __u8 u8; +typedef __s16 s16; +typedef __u16 u16; +typedef __s32 s32; +typedef __u32 u32; +typedef __s64 s64; +typedef __u64 u64; + +enum { + false = 0, + true = 1, +}; + +#ifdef __CHECKER__ +#define __bitwise__ __attribute__((bitwise)) +#else +#define __bitwise__ +#endif +#define __bitwise __bitwise__ + +typedef __u16 __bitwise __le16; +typedef __u16 __bitwise __be16; +typedef __u32 __bitwise __le32; +typedef __u32 __bitwise __be32; +typedef __u64 __bitwise __le64; +typedef __u64 __bitwise __be64; + +typedef __u16 __bitwise __sum16; +typedef __u32 __bitwise __wsum; + +#endif /* __PROFILER_H */ |