Commit 843bd2b3 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'bpf-Improve-LRU-map-lookup-performance' 



Martin KaFai Lau says:

====================
bpf: Improve LRU map lookup performance

This patchset improves the lookup performance of the LRU map.
Please see individual patch for details.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 08daaec7 bb9b9f88

kernel/bpf/bpf_lru_list.h

+2 −1
Original line number Diff line number Diff line
@@ -69,6 +69,7 @@ static inline void bpf_lru_node_set_ref(struct bpf_lru_node *node) 
	/* ref is an approximation on access frequency.  It does not

	 * have to be very accurate.  Hence, no protection is used.

	 */

	if (!node->ref)

		node->ref = 1;

}

kernel/bpf/hashtab.c

+24 −0
Original line number Diff line number Diff line
@@ -514,6 +514,29 @@ static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key) 
	return NULL;

}



static u32 htab_lru_map_gen_lookup(struct bpf_map *map,

				   struct bpf_insn *insn_buf)

{

	struct bpf_insn *insn = insn_buf;

	const int ret = BPF_REG_0;

	const int ref_reg = BPF_REG_1;



	*insn++ = BPF_EMIT_CALL((u64 (*)(u64, u64, u64, u64, u64))__htab_map_lookup_elem);

	*insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 4);

	*insn++ = BPF_LDX_MEM(BPF_B, ref_reg, ret,

			      offsetof(struct htab_elem, lru_node) +

			      offsetof(struct bpf_lru_node, ref));

	*insn++ = BPF_JMP_IMM(BPF_JNE, ref_reg, 0, 1);

	*insn++ = BPF_ST_MEM(BPF_B, ret,

			     offsetof(struct htab_elem, lru_node) +

			     offsetof(struct bpf_lru_node, ref),

			     1);

	*insn++ = BPF_ALU64_IMM(BPF_ADD, ret,

				offsetof(struct htab_elem, key) +

				round_up(map->key_size, 8));

	return insn - insn_buf;

}



/* It is called from the bpf_lru_list when the LRU needs to delete

 * older elements from the htab.

 */
@@ -1137,6 +1160,7 @@ const struct bpf_map_ops htab_lru_map_ops = { 
	.map_lookup_elem = htab_lru_map_lookup_elem,

	.map_update_elem = htab_lru_map_update_elem,

	.map_delete_elem = htab_lru_map_delete_elem,

	.map_gen_lookup = htab_lru_map_gen_lookup,

};



/* Called from eBPF program */

samples/bpf/map_perf_test_kern.c

+38 −6
Original line number Diff line number Diff line
@@ -88,6 +88,13 @@ struct bpf_map_def SEC("maps") array_map = { 
	.max_entries = MAX_ENTRIES,

};



struct bpf_map_def SEC("maps") lru_hash_lookup_map = {

	.type = BPF_MAP_TYPE_LRU_HASH,

	.key_size = sizeof(u32),

	.value_size = sizeof(long),

	.max_entries = MAX_ENTRIES,

};



SEC("kprobe/sys_getuid")

int stress_hmap(struct pt_regs *ctx)

{
@@ -148,12 +155,23 @@ int stress_percpu_hmap_alloc(struct pt_regs *ctx) 
SEC("kprobe/sys_connect")

int stress_lru_hmap_alloc(struct pt_regs *ctx)

{

	char fmt[] = "Failed at stress_lru_hmap_alloc. ret:%dn";

	union {

		u16 dst6[8];

		struct {

			u16 magic0;

			u16 magic1;

			u16 tcase;

			u16 unused16;

			u32 unused32;

			u32 key;

		};

	} test_params;

	struct sockaddr_in6 *in6;

	u16 test_case, dst6[8];

	u16 test_case;

	int addrlen, ret;

	char fmt[] = "Failed at stress_lru_hmap_alloc. ret:%d\n";

	long val = 1;

	u32 key = bpf_get_prandom_u32();

	u32 key = 0;



	in6 = (struct sockaddr_in6 *)PT_REGS_PARM2(ctx);

	addrlen = (int)PT_REGS_PARM3(ctx);
@@ -161,14 +179,18 @@ int stress_lru_hmap_alloc(struct pt_regs *ctx) 
	if (addrlen != sizeof(*in6))

		return 0;



	ret = bpf_probe_read(dst6, sizeof(dst6), &in6->sin6_addr);

	ret = bpf_probe_read(test_params.dst6, sizeof(test_params.dst6),

			     &in6->sin6_addr);

	if (ret)

		goto done;



	if (dst6[0] != 0xdead || dst6[1] != 0xbeef)

	if (test_params.magic0 != 0xdead ||

	    test_params.magic1 != 0xbeef)

		return 0;



	test_case = dst6[7];

	test_case = test_params.tcase;

	if (test_case != 3)

		key = bpf_get_prandom_u32();



	if (test_case == 0) {

		ret = bpf_map_update_elem(&lru_hash_map, &key, &val, BPF_ANY);
@@ -188,6 +210,16 @@ int stress_lru_hmap_alloc(struct pt_regs *ctx) 


		ret = bpf_map_update_elem(nolocal_lru_map, &key, &val,

					  BPF_ANY);

	} else if (test_case == 3) {

		u32 i;



		key = test_params.key;



#pragma clang loop unroll(full)

		for (i = 0; i < 32; i++) {

			bpf_map_lookup_elem(&lru_hash_lookup_map, &key);

			key++;

		}

	} else {

		ret = -EINVAL;

	}

samples/bpf/map_perf_test_user.c

+74 −3
Original line number Diff line number Diff line
@@ -46,6 +46,7 @@ enum test_type { 
	HASH_LOOKUP,

	ARRAY_LOOKUP,

	INNER_LRU_HASH_PREALLOC,

	LRU_HASH_LOOKUP,

	NR_TESTS,

};
@@ -60,6 +61,7 @@ const char *test_map_names[NR_TESTS] = { 
	[HASH_LOOKUP] = "hash_map",

	[ARRAY_LOOKUP] = "array_map",

	[INNER_LRU_HASH_PREALLOC] = "inner_lru_hash_map",

	[LRU_HASH_LOOKUP] = "lru_hash_lookup_map",

};



static int test_flags = ~0;
@@ -67,6 +69,8 @@ static uint32_t num_map_entries; 
static uint32_t inner_lru_hash_size;

static int inner_lru_hash_idx = -1;

static int array_of_lru_hashs_idx = -1;

static int lru_hash_lookup_idx = -1;

static int lru_hash_lookup_test_entries = 32;

static uint32_t max_cnt = 1000000;



static int check_test_flags(enum test_type t)
@@ -86,6 +90,32 @@ static void test_hash_prealloc(int cpu) 
	       cpu, max_cnt * 1000000000ll / (time_get_ns() - start_time));

}



static int pre_test_lru_hash_lookup(int tasks)

{

	int fd = map_fd[lru_hash_lookup_idx];

	uint32_t key;

	long val = 1;

	int ret;



	if (num_map_entries > lru_hash_lookup_test_entries)

		lru_hash_lookup_test_entries = num_map_entries;



	/* Populate the lru_hash_map for LRU_HASH_LOOKUP perf test.

	 *

	 * It is fine that the user requests for a map with

	 * num_map_entries < 32 and some of the later lru hash lookup

	 * may return not found.  For LRU map, we are not interested

	 * in such small map performance.

	 */

	for (key = 0; key < lru_hash_lookup_test_entries; key++) {

		ret = bpf_map_update_elem(fd, &key, &val, BPF_NOEXIST);

		if (ret)

			return ret;

	}



	return 0;

}



static void do_test_lru(enum test_type test, int cpu)

{

	static int inner_lru_map_fds[MAX_NR_CPUS];
@@ -135,13 +165,17 @@ static void do_test_lru(enum test_type test, int cpu) 


	if (test == LRU_HASH_PREALLOC) {

		test_name = "lru_hash_map_perf";

		in6.sin6_addr.s6_addr16[7] = 0;

		in6.sin6_addr.s6_addr16[2] = 0;

	} else if (test == NOCOMMON_LRU_HASH_PREALLOC) {

		test_name = "nocommon_lru_hash_map_perf";

		in6.sin6_addr.s6_addr16[7] = 1;

		in6.sin6_addr.s6_addr16[2] = 1;

	} else if (test == INNER_LRU_HASH_PREALLOC) {

		test_name = "inner_lru_hash_map_perf";

		in6.sin6_addr.s6_addr16[7] = 2;

		in6.sin6_addr.s6_addr16[2] = 2;

	} else if (test == LRU_HASH_LOOKUP) {

		test_name = "lru_hash_lookup_perf";

		in6.sin6_addr.s6_addr16[2] = 3;

		in6.sin6_addr.s6_addr32[3] = 0;

	} else {

		assert(0);

	}
@@ -150,6 +184,11 @@ static void do_test_lru(enum test_type test, int cpu) 
	for (i = 0; i < max_cnt; i++) {

		ret = connect(-1, (const struct sockaddr *)&in6, sizeof(in6));

		assert(ret == -1 && errno == EBADF);

		if (in6.sin6_addr.s6_addr32[3] <

		    lru_hash_lookup_test_entries - 32)

			in6.sin6_addr.s6_addr32[3] += 32;

		else

			in6.sin6_addr.s6_addr32[3] = 0;

	}

	printf("%d:%s pre-alloc %lld events per sec\n",

	       cpu, test_name,
@@ -171,6 +210,11 @@ static void test_inner_lru_hash_prealloc(int cpu) 
	do_test_lru(INNER_LRU_HASH_PREALLOC, cpu);

}



static void test_lru_hash_lookup(int cpu)

{

	do_test_lru(LRU_HASH_LOOKUP, cpu);

}



static void test_percpu_hash_prealloc(int cpu)

{

	__u64 start_time;
@@ -243,6 +287,11 @@ static void test_array_lookup(int cpu) 
	       cpu, max_cnt * 1000000000ll * 64 / (time_get_ns() - start_time));

}



typedef int (*pre_test_func)(int tasks);

const pre_test_func pre_test_funcs[] = {

	[LRU_HASH_LOOKUP] = pre_test_lru_hash_lookup,

};



typedef void (*test_func)(int cpu);

const test_func test_funcs[] = {

	[HASH_PREALLOC] = test_hash_prealloc,
@@ -255,8 +304,25 @@ const test_func test_funcs[] = { 
	[HASH_LOOKUP] = test_hash_lookup,

	[ARRAY_LOOKUP] = test_array_lookup,

	[INNER_LRU_HASH_PREALLOC] = test_inner_lru_hash_prealloc,

	[LRU_HASH_LOOKUP] = test_lru_hash_lookup,

};



static int pre_test(int tasks)

{

	int i;



	for (i = 0; i < NR_TESTS; i++) {

		if (pre_test_funcs[i] && check_test_flags(i)) {

			int ret = pre_test_funcs[i](tasks);



			if (ret)

				return ret;

		}

	}



	return 0;

}



static void loop(int cpu)

{

	cpu_set_t cpuset;
@@ -277,6 +343,8 @@ static void run_perf_test(int tasks) 
	pid_t pid[tasks];

	int i;



	assert(!pre_test(tasks));



	for (i = 0; i < tasks; i++) {

		pid[i] = fork();

		if (pid[i] == 0) {
@@ -344,6 +412,9 @@ static void fixup_map(struct bpf_map_data *map, int idx) 
		array_of_lru_hashs_idx = idx;

	}



	if (!strcmp("lru_hash_lookup_map", map->name))

		lru_hash_lookup_idx = idx;



	if (num_map_entries <= 0)

		return;