From 47c09d6a9f6794caface4ad50930460b82d7c670 Mon Sep 17 00:00:00 2001 From: Song Liu Date: Mon, 9 Mar 2020 10:32:15 -0700 Subject: 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 Signed-off-by: Daniel Borkmann Reviewed-by: Quentin Monnet Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20200309173218.2739965-2-songliubraving@fb.com --- tools/bpf/bpftool/skeleton/profiler.h | 47 +++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 tools/bpf/bpftool/skeleton/profiler.h (limited to 'tools/bpf/bpftool/skeleton/profiler.h') 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 */ -- cgit v1.2.3 From fe4eb069edb7ab845160350d9e67d572c026a4a7 Mon Sep 17 00:00:00 2001 From: Tobias Klauser Date: Thu, 12 Mar 2020 14:03:30 +0100 Subject: bpftool: Use linux/types.h from source tree for profiler build When compiling bpftool on a system where the /usr/include/asm symlink doesn't exist (e.g. on an Ubuntu system without gcc-multilib installed), the build fails with: CLANG skeleton/profiler.bpf.o In file included from skeleton/profiler.bpf.c:4: In file included from /usr/include/linux/bpf.h:11: /usr/include/linux/types.h:5:10: fatal error: 'asm/types.h' file not found #include ^~~~~~~~~~~~~ 1 error generated. make: *** [Makefile:123: skeleton/profiler.bpf.o] Error 1 This indicates that the build is using linux/types.h from system headers instead of source tree headers. To fix this, adjust the clang search path to include the necessary headers from tools/testing/selftests/bpf/include/uapi and tools/include/uapi. Also use __bitwise__ instead of __bitwise in skeleton/profiler.h to avoid clashing with the definition in tools/testing/selftests/bpf/include/uapi/linux/types.h. Signed-off-by: Tobias Klauser Signed-off-by: Daniel Borkmann Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20200312130330.32239-1-tklauser@distanz.ch --- tools/bpf/bpftool/Makefile | 5 ++++- tools/bpf/bpftool/skeleton/profiler.h | 17 ++++++++--------- 2 files changed, 12 insertions(+), 10 deletions(-) (limited to 'tools/bpf/bpftool/skeleton/profiler.h') diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile index 20a90d8450f8..f294f6c1e795 100644 --- a/tools/bpf/bpftool/Makefile +++ b/tools/bpf/bpftool/Makefile @@ -120,7 +120,10 @@ $(OUTPUT)_bpftool: $(_OBJS) $(LIBBPF) $(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(_OBJS) $(LIBS) skeleton/profiler.bpf.o: skeleton/profiler.bpf.c - $(QUIET_CLANG)$(CLANG) -I$(srctree)/tools/lib -g -O2 -target bpf -c $< -o $@ + $(QUIET_CLANG)$(CLANG) \ + -I$(srctree)/tools/include/uapi/ \ + -I$(srctree)/tools/testing/selftests/bpf/include/uapi \ + -I$(srctree)/tools/lib -g -O2 -target bpf -c $< -o $@ profiler.skel.h: $(OUTPUT)_bpftool skeleton/profiler.bpf.o $(QUIET_GEN)$(OUTPUT)./_bpftool gen skeleton skeleton/profiler.bpf.o > $@ diff --git a/tools/bpf/bpftool/skeleton/profiler.h b/tools/bpf/bpftool/skeleton/profiler.h index e03b53eae767..1f767e9510f7 100644 --- a/tools/bpf/bpftool/skeleton/profiler.h +++ b/tools/bpf/bpftool/skeleton/profiler.h @@ -32,16 +32,15 @@ enum { #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__ __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; +typedef __u16 __bitwise__ __sum16; +typedef __u32 __bitwise__ __wsum; #endif /* __PROFILER_H */ -- cgit v1.2.3