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samples/bpf: add lpm-trie benchmark

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Extend the map_perf_test_{user,kern}.c infrastructure to stress test
lpm-trie lookups. We hook into the kprobe on sys_gettid() and measure
the latency depending on trie size and lookup count.

On my Intel Haswell i7-6400U, a single gettid() syscall with an empty
bpf program takes roughly 6.5us on my system. Lookups in empty tries
take ~1.8us on first try, ~0.9us on retries. Lookups in tries with 8192
entries take ~7.1us (on the first _and_ any subsequent try).

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Daniel Mack <daniel@zonque.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Herrmann 2017-01-21 17:26:13 +01:00 committed by David S. Miller
parent 4d3381f5a3
commit b8a943e294
2 changed files with 79 additions and 0 deletions
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30
samples/bpf/map_perf_test_kern.c
View File

@ -57,6 +57,14 @@ struct bpf_map_def SEC("maps") percpu_hash_map_alloc = {
.map_flags = BPF_F_NO_PREALLOC,
};
struct bpf_map_def SEC("maps") lpm_trie_map_alloc = {
.type = BPF_MAP_TYPE_LPM_TRIE,
.key_size = 8,
.value_size = sizeof(long),
.max_entries = 10000,
.map_flags = BPF_F_NO_PREALLOC,
};
SEC("kprobe/sys_getuid")
int stress_hmap(struct pt_regs *ctx)
{
@ -135,5 +143,27 @@ int stress_percpu_lru_hmap_alloc(struct pt_regs *ctx)
return 0;
}
SEC("kprobe/sys_gettid")
int stress_lpm_trie_map_alloc(struct pt_regs *ctx)
{
union {
u32 b32[2];
u8 b8[8];
} key;
unsigned int i;
key.b32[0] = 32;
key.b8[4] = 192;
key.b8[5] = 168;
key.b8[6] = 0;
key.b8[7] = 1;
#pragma clang loop unroll(full)
for (i = 0; i < 32; ++i)
bpf_map_lookup_elem(&lpm_trie_map_alloc, &key);
return 0;
}
char _license[] SEC("license") = "GPL";
u32 _version SEC("version") = LINUX_VERSION_CODE;

49
samples/bpf/map_perf_test_user.c
View File

@ -37,6 +37,7 @@ static __u64 time_get_ns(void)
#define PERCPU_HASH_KMALLOC (1 << 3)
#define LRU_HASH_PREALLOC (1 << 4)
#define PERCPU_LRU_HASH_PREALLOC (1 << 5)
#define LPM_KMALLOC (1 << 6)
static int test_flags = ~0;
@ -112,6 +113,18 @@ static void test_percpu_hash_kmalloc(int cpu)
cpu, MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
}
static void test_lpm_kmalloc(int cpu)
{
__u64 start_time;
int i;
start_time = time_get_ns();
for (i = 0; i < MAX_CNT; i++)
syscall(__NR_gettid);
printf("%d:lpm_perf kmalloc %lld events per sec\n",
cpu, MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
}
static void loop(int cpu)
{
cpu_set_t cpuset;
@ -137,6 +150,9 @@ static void loop(int cpu)
if (test_flags & PERCPU_LRU_HASH_PREALLOC)
test_percpu_lru_hash_prealloc(cpu);
if (test_flags & LPM_KMALLOC)
test_lpm_kmalloc(cpu);
}
static void run_perf_test(int tasks)
@ -162,6 +178,37 @@ static void run_perf_test(int tasks)
}
}
static void fill_lpm_trie(void)
{
struct bpf_lpm_trie_key *key;
unsigned long value = 0;
unsigned int i;
int r;
key = alloca(sizeof(*key) + 4);
key->prefixlen = 32;
for (i = 0; i < 512; ++i) {
key->prefixlen = rand() % 33;
key->data[0] = rand() & 0xff;
key->data[1] = rand() & 0xff;
key->data[2] = rand() & 0xff;
key->data[3] = rand() & 0xff;
r = bpf_map_update_elem(map_fd[6], key, &value, 0);
assert(!r);
}
key->prefixlen = 32;
key->data[0] = 192;
key->data[1] = 168;
key->data[2] = 0;
key->data[3] = 1;
value = 128;
r = bpf_map_update_elem(map_fd[6], key, &value, 0);
assert(!r);
}
int main(int argc, char **argv)
{
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
@ -182,6 +229,8 @@ int main(int argc, char **argv)
return 1;
}
fill_lpm_trie();
run_perf_test(num_cpu);
return 0;