diff options
author | Alexei Starovoitov <ast@fb.com> | 2017-03-15 18:26:44 -0700 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2017-03-16 20:44:12 -0700 |
commit | 95ff141e52f84f476fcde50560f42d4f118539c0 (patch) | |
tree | f35cf082e9d34087212bff37049f505389b38d57 /samples/bpf/map_perf_test_user.c | |
parent | 9015d2f5953590e8273392b44c2b0f864350b427 (diff) |
samples/bpf: add map_lookup microbenchmark
$ map_perf_test 128
speed of HASH bpf_map_lookup_elem() in lookups per second
w/o JIT w/JIT
before 46M 58M
after 42M 74M
perf report
before:
54.23% map_perf_test [kernel.kallsyms] [k] __htab_map_lookup_elem
14.24% map_perf_test [kernel.kallsyms] [k] lookup_elem_raw
8.84% map_perf_test [kernel.kallsyms] [k] htab_map_lookup_elem
5.93% map_perf_test [kernel.kallsyms] [k] bpf_map_lookup_elem
2.30% map_perf_test [kernel.kallsyms] [k] bpf_prog_da4fc6a3f41761a2
1.49% map_perf_test [kernel.kallsyms] [k] kprobe_ftrace_handler
after:
60.03% map_perf_test [kernel.kallsyms] [k] __htab_map_lookup_elem
18.07% map_perf_test [kernel.kallsyms] [k] lookup_elem_raw
2.91% map_perf_test [kernel.kallsyms] [k] bpf_prog_da4fc6a3f41761a2
1.94% map_perf_test [kernel.kallsyms] [k] _einittext
1.90% map_perf_test [kernel.kallsyms] [k] __audit_syscall_exit
1.72% map_perf_test [kernel.kallsyms] [k] kprobe_ftrace_handler
Notice that bpf_map_lookup_elem() and htab_map_lookup_elem() are trivial
functions, yet they take sizeable amount of cpu time.
htab_map_gen_lookup() removes bpf_map_lookup_elem() and converts
htab_map_lookup_elem() into three BPF insns which causing cpu time
for bpf_prog_da4fc6a3f41761a2() slightly increase.
$ map_perf_test 256
speed of ARRAY bpf_map_lookup_elem() in lookups per second
w/o JIT w/JIT
before 97M 174M
after 64M 280M
before:
37.33% map_perf_test [kernel.kallsyms] [k] array_map_lookup_elem
13.95% map_perf_test [kernel.kallsyms] [k] bpf_map_lookup_elem
6.54% map_perf_test [kernel.kallsyms] [k] bpf_prog_da4fc6a3f41761a2
4.57% map_perf_test [kernel.kallsyms] [k] kprobe_ftrace_handler
after:
32.86% map_perf_test [kernel.kallsyms] [k] bpf_prog_da4fc6a3f41761a2
6.54% map_perf_test [kernel.kallsyms] [k] kprobe_ftrace_handler
array_map_gen_lookup() removes calls to array_map_lookup_elem()
and bpf_map_lookup_elem() and replaces them with 7 bpf insns.
The performance without JIT is slower, since executing extra insns
in the interpreter is slower than running native C code,
but with JIT the performance gains are obvious,
since native C->x86 code is replaced with fewer bpf->x86 instructions.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'samples/bpf/map_perf_test_user.c')
-rw-r--r-- | samples/bpf/map_perf_test_user.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/samples/bpf/map_perf_test_user.c b/samples/bpf/map_perf_test_user.c index 680260a91f50..e29ff318a793 100644 --- a/samples/bpf/map_perf_test_user.c +++ b/samples/bpf/map_perf_test_user.c @@ -38,6 +38,8 @@ static __u64 time_get_ns(void) #define LRU_HASH_PREALLOC (1 << 4) #define PERCPU_LRU_HASH_PREALLOC (1 << 5) #define LPM_KMALLOC (1 << 6) +#define HASH_LOOKUP (1 << 7) +#define ARRAY_LOOKUP (1 << 8) static int test_flags = ~0; @@ -125,6 +127,30 @@ static void test_lpm_kmalloc(int cpu) cpu, MAX_CNT * 1000000000ll / (time_get_ns() - start_time)); } +static void test_hash_lookup(int cpu) +{ + __u64 start_time; + int i; + + start_time = time_get_ns(); + for (i = 0; i < MAX_CNT; i++) + syscall(__NR_getpgid, 0); + printf("%d:hash_lookup %lld lookups per sec\n", + cpu, MAX_CNT * 1000000000ll * 64 / (time_get_ns() - start_time)); +} + +static void test_array_lookup(int cpu) +{ + __u64 start_time; + int i; + + start_time = time_get_ns(); + for (i = 0; i < MAX_CNT; i++) + syscall(__NR_getpgrp, 0); + printf("%d:array_lookup %lld lookups per sec\n", + cpu, MAX_CNT * 1000000000ll * 64 / (time_get_ns() - start_time)); +} + static void loop(int cpu) { cpu_set_t cpuset; @@ -153,6 +179,12 @@ static void loop(int cpu) if (test_flags & LPM_KMALLOC) test_lpm_kmalloc(cpu); + + if (test_flags & HASH_LOOKUP) + test_hash_lookup(cpu); + + if (test_flags & ARRAY_LOOKUP) + test_array_lookup(cpu); } static void run_perf_test(int tasks) |