The test program run result: $ ./test_maps ... measure_lookup: max_entries 1000000, batch 10, time 342 measure_lookup: max_entries 1000000, batch 1000, time 295 measure_lookup: max_entries 1000000, batch 1000000, time 270 measure_lookup: max_entries 1000000, no batching, time 1346 measure_lookup_delete: max_entries 1000000, batch 10, time 433 measure_lookup_delete: max_entries 1000000, batch 1000, time 363 measure_lookup_delete: max_entries 1000000, batch 1000000, time 357 measure_lookup_delete: max_entries 1000000, not batch, time 1894 measure_delete: max_entries 1000000, batch, time 220 measure_delete: max_entries 1000000, not batch, time 1289 test_map_batch_perf:PASS ...
The test is running on a qemu VM environment. The time unit is millisecond. A simple hash table with 1M elements is created. For lookup and lookup_and_deletion, since buffer allocation is needed to hold the lookup results, three different batch sizes (10, 1000, and 1M) are tried. The performance without batching is also measured. A batch size of 10 can already improves performance dramatically, more than 70%, and increasing batch size may continue to improve performance, but with diminishing returns. For delete, the batch API provides a mechanism to delete all elements in the map, which is used here. The deletion of the whole map improves performance by 80% compared to non-batch mechanism. Signed-off-by: Yonghong Song <[email protected]> --- .../selftests/bpf/map_tests/map_batch_perf.c | 242 ++++++++++++++++++ 1 file changed, 242 insertions(+) create mode 100644 tools/testing/selftests/bpf/map_tests/map_batch_perf.c diff --git a/tools/testing/selftests/bpf/map_tests/map_batch_perf.c b/tools/testing/selftests/bpf/map_tests/map_batch_perf.c new file mode 100644 index 000000000000..42d95651e1ac --- /dev/null +++ b/tools/testing/selftests/bpf/map_tests/map_batch_perf.c @@ -0,0 +1,242 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2019 Facebook */ +#include <stdio.h> +#include <errno.h> +#include <string.h> +#include <sys/time.h> + +#include <bpf/bpf.h> +#include <bpf/libbpf.h> + +#include <test_maps.h> + +/* Test map batch performance. + * Test three common scenarios: + * - batched lookup + * - batched lookup and delete + * - batched deletion + */ +static void map_batch_update(int map_fd, __u32 max_entries, int *keys, + int *values) +{ + int i, err; + + for (i = 0; i < max_entries; i++) { + keys[i] = i + 1; + values[i] = i + 2; + } + + err = bpf_map_update_batch(map_fd, keys, values, &max_entries, 0, 0); + CHECK(err, "bpf_map_update_batch()", "error:%s\n", strerror(errno)); +} + +static unsigned long util_gettime(void) +{ + struct timeval tv; + + gettimeofday(&tv, NULL); + return (tv.tv_sec * 1000) + (tv.tv_usec / 1000); +} + +static void measure_lookup(int map_fd, __u32 max_entries, int *keys, + int *values) +{ + __u32 batches[3] = {10, 1000}; + int err, key, value, option; + unsigned long start, end; + void *p_key, *p_next_key; + __u32 count, total; + + map_batch_update(map_fd, max_entries, keys, values); + + /* batched */ + batches[2] = max_entries; + for (option = 0; option < 3; option++) { + p_key = NULL; + p_next_key = &key; + count = batches[option]; + start = util_gettime(); + total = 0; + + while (true) { + err = bpf_map_lookup_batch(map_fd, p_key, &p_next_key, + keys, values, &count, 0, 0); + CHECK(err, "bpf_map_lookup_batch()", "error: %s\n", + strerror(errno)); + + total += count; + if (!p_next_key) + break; + + if (!p_key) + p_key = p_next_key; + } + + end = util_gettime(); + CHECK(total != max_entries, + "checking total", "total %u, max_entries %u\n", + total, max_entries); + printf("%s: max_entries %u, batch %u, time %ld\n", __func__, + max_entries, batches[option], end - start); + } + + /* not batched */ + start = util_gettime(); + p_key = NULL; + p_next_key = &key; + while (!bpf_map_get_next_key(map_fd, p_key, p_next_key)) { + err = bpf_map_lookup_elem(map_fd, p_next_key, &value); + CHECK(err, "bpf_map_lookup_elem()", "error: %s\n", + strerror(errno)); + p_key = p_next_key; + } + end = util_gettime(); + printf("%s: max_entries %u, no batching, time %ld\n", __func__, + max_entries, end - start); +} + +static void measure_lookup_delete(int map_fd, __u32 max_entries, int *keys, + int *values) +{ + int err, key, next_key, value, option; + __u32 batches[3] = {10, 1000}; + unsigned long start, end; + void *p_key, *p_next_key; + __u32 count, total; + + /* batched */ + batches[2] = max_entries; + for (option = 0; option < 3; option++) { + map_batch_update(map_fd, max_entries, keys, values); + p_key = NULL; + p_next_key = &key; + count = batches[option]; + start = util_gettime(); + total = 0; + + while (true) { + err = bpf_map_lookup_and_delete_batch(map_fd, p_key, + &p_next_key, keys, values, &count, 0, 0); + CHECK(err, "bpf_map_lookup_and_delete_batch()", + "error: %s\n", strerror(errno)); + + total += count; + if (!p_next_key) + break; + + if (!p_key) + p_key = p_next_key; + } + + end = util_gettime(); + CHECK(total != max_entries, + "checking total", "total %u, max_entries %u\n", + total, max_entries); + printf("%s: max_entries %u, batch %u, time %ld\n", __func__, + max_entries, batches[option], end - start); + } + + /* not batched */ + map_batch_update(map_fd, max_entries, keys, values); + start = util_gettime(); + p_key = NULL; + p_next_key = &key; + err = bpf_map_get_next_key(map_fd, p_key, p_next_key); + CHECK(err, "bpf_map_get_next_key()", "error: %s\n", strerror(errno)); + err = bpf_map_lookup_elem(map_fd, p_next_key, &value); + CHECK(err, "bpf_map_lookup_elem()", "error: %s\n", strerror(errno)); + + p_key = p_next_key; + p_next_key = &next_key; + while (!bpf_map_get_next_key(map_fd, p_key, p_next_key)) { + err = bpf_map_delete_elem(map_fd, p_key); + CHECK(err, "bpf_map_delete_elem()", "error: %s\n", + strerror(errno)); + + err = bpf_map_lookup_elem(map_fd, p_next_key, &value); + CHECK(err, "bpf_map_lookup_elem()", "error: %s\n", + strerror(errno)); + + p_key = p_next_key; + p_next_key = (p_next_key == &key) ? &next_key : &key; + } + err = bpf_map_delete_elem(map_fd, p_key); + CHECK(err, "bpf_map_delete_elem()", "error: %s\n", + strerror(errno)); + end = util_gettime(); + printf("%s: max_entries %u, not batch, time %ld\n", __func__, + max_entries, end - start); +} + +static void measure_delete(int map_fd, __u32 max_entries, int *keys, + int *values) +{ + unsigned long start, end; + void *p_key, *p_next_key; + int err, key, next_key; + __u32 count; + + /* batched */ + map_batch_update(map_fd, max_entries, keys, values); + count = 0; + p_next_key = &key; + start = util_gettime(); + err = bpf_map_delete_batch(map_fd, NULL, NULL, NULL, &count, 0, 0); + end = util_gettime(); + CHECK(err, "bpf_map_delete_batch()", "error: %s\n", strerror(errno)); + CHECK(count != max_entries, "bpf_map_delete_batch()", + "count = %u, max_entries = %u\n", count, max_entries); + + printf("%s: max_entries %u, batch, time %ld\n", __func__, + max_entries, end - start); + + map_batch_update(map_fd, max_entries, keys, values); + p_key = NULL; + p_next_key = &key; + start = util_gettime(); + err = bpf_map_get_next_key(map_fd, p_key, p_next_key); + CHECK(err, "bpf_map_get_next_key()", "error: %s\n", strerror(errno)); + + p_key = p_next_key; + p_next_key = &next_key; + while (!bpf_map_get_next_key(map_fd, p_key, p_next_key)) { + err = bpf_map_delete_elem(map_fd, p_key); + CHECK(err, "bpf_map_delete_elem()", "error: %s\n", + strerror(errno)); + p_key = p_next_key; + p_next_key = (p_next_key == &key) ? &next_key : &key; + } + err = bpf_map_delete_elem(map_fd, p_key); + CHECK(err, "bpf_map_delete_elem()", "error: %s\n", + strerror(errno)); + end = util_gettime(); + printf("%s: max_entries %u, not batch, time %ld\n", __func__, + max_entries, end - start); +} + +void test_map_batch_perf(void) +{ + struct bpf_create_map_attr xattr = { + .name = "hash_map", + .map_type = BPF_MAP_TYPE_HASH, + .key_size = sizeof(int), + .value_size = sizeof(int), + }; + const __u32 max_entries = 1000000; // 1M entries for the hash table + int map_fd, *keys, *values; + + xattr.max_entries = max_entries; + map_fd = bpf_create_map_xattr(&xattr); + CHECK(map_fd == -1, + "bpf_create_map_xattr()", "error:%s\n", strerror(errno)); + + keys = malloc(max_entries * sizeof(int)); + values = malloc(max_entries * sizeof(int)); + CHECK(!keys || !values, "malloc()", "error:%s\n", strerror(errno)); + + measure_lookup(map_fd, max_entries, keys, values); + measure_lookup_delete(map_fd, max_entries, keys, values); + measure_delete(map_fd, max_entries, keys, values); + + printf("%s:PASS\n", __func__); +} -- 2.17.1
