From 3a5795b83d578cc542a92c94399946258cf1a2af Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Fri, 14 Apr 2017 10:30:30 -0700 Subject: bpf: lru: Add map-in-map LRU example This patch adds a map-in-map LRU example. If we know only a subset of cores will use the LRU, we can allocate a common LRU list per targeting core and store it into an array-of-hashs. It allows using the common LRU map with map-update performance comparable to the BPF_F_NO_COMMON_LRU map but without wasting memory on the unused cores that we know they will never access the LRU map. BPF_F_NO_COMMON_LRU: > map_perf_test 32 8 10000000 10000000 | awk '{sum += $3}END{print sum}' 9234314 (9.23M/s) map-in-map LRU: > map_perf_test 512 8 1260000 80000000 | awk '{sum += $3}END{print sum}' 9962743 (9.96M/s) Notes that the max_entries for the map-in-map LRU test is 1260000 which is the max_entries for each inner LRU map. 8 processes have been started, so 8 * 1260000 = 10080000 (~10M) which is close to what is used in the BPF_F_NO_COMMON_LRU test. Signed-off-by: Martin KaFai Lau Signed-off-by: David S. Miller --- samples/bpf/map_perf_test_kern.c | 34 +++++++++++++++++++++++++++++++--- 1 file changed, 31 insertions(+), 3 deletions(-) (limited to 'samples/bpf/map_perf_test_kern.c') diff --git a/samples/bpf/map_perf_test_kern.c b/samples/bpf/map_perf_test_kern.c index 404ed53b8a53..245165817fbe 100644 --- a/samples/bpf/map_perf_test_kern.c +++ b/samples/bpf/map_perf_test_kern.c @@ -11,6 +11,7 @@ #include "bpf_helpers.h" #define MAX_ENTRIES 1000 +#define MAX_NR_CPUS 1024 struct bpf_map_def SEC("maps") hash_map = { .type = BPF_MAP_TYPE_HASH, @@ -34,6 +35,19 @@ struct bpf_map_def SEC("maps") nocommon_lru_hash_map = { .map_flags = BPF_F_NO_COMMON_LRU, }; +struct bpf_map_def SEC("maps") inner_lru_hash_map = { + .type = BPF_MAP_TYPE_LRU_HASH, + .key_size = sizeof(u32), + .value_size = sizeof(long), + .max_entries = MAX_ENTRIES, +}; + +struct bpf_map_def SEC("maps") array_of_lru_hashs = { + .type = BPF_MAP_TYPE_ARRAY_OF_MAPS, + .key_size = sizeof(u32), + .max_entries = MAX_NR_CPUS, +}; + struct bpf_map_def SEC("maps") percpu_hash_map = { .type = BPF_MAP_TYPE_PERCPU_HASH, .key_size = sizeof(u32), @@ -154,13 +168,27 @@ int stress_lru_hmap_alloc(struct pt_regs *ctx) test_case = dst6[7]; - if (test_case == 0) + if (test_case == 0) { ret = bpf_map_update_elem(&lru_hash_map, &key, &val, BPF_ANY); - else if (test_case == 1) + } else if (test_case == 1) { ret = bpf_map_update_elem(&nocommon_lru_hash_map, &key, &val, BPF_ANY); - else + } else if (test_case == 2) { + void *nolocal_lru_map; + int cpu = bpf_get_smp_processor_id(); + + nolocal_lru_map = bpf_map_lookup_elem(&array_of_lru_hashs, + &cpu); + if (!nolocal_lru_map) { + ret = -ENOENT; + goto done; + } + + ret = bpf_map_update_elem(nolocal_lru_map, &key, &val, + BPF_ANY); + } else { ret = -EINVAL; + } done: if (ret) -- cgit v1.2.3