From 89dc8d0c38e0df27e580876a1681a55c686a51ff Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Fri, 2 Sep 2022 14:10:46 -0700 Subject: [PATCH] samples/bpf: Reduce syscall overhead in map_perf_test. Make map_perf_test for preallocated and non-preallocated hash map spend more time inside bpf program to focus performance analysis on the speed of update/lookup/delete operations performed by bpf program. It makes 'perf report' of bpf_mem_alloc look like: 11.76% map_perf_test [k] _raw_spin_lock_irqsave 11.26% map_perf_test [k] htab_map_update_elem 9.70% map_perf_test [k] _raw_spin_lock 9.47% map_perf_test [k] htab_map_delete_elem 8.57% map_perf_test [k] memcpy_erms 5.58% map_perf_test [k] alloc_htab_elem 4.09% map_perf_test [k] __htab_map_lookup_elem 3.44% map_perf_test [k] syscall_exit_to_user_mode 3.13% map_perf_test [k] lookup_nulls_elem_raw 3.05% map_perf_test [k] migrate_enable 3.04% map_perf_test [k] memcmp 2.67% map_perf_test [k] unit_free 2.39% map_perf_test [k] lookup_elem_raw Reduce default iteration count as well to make 'map_perf_test' quick enough even on debug kernels. Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Acked-by: Kumar Kartikeya Dwivedi Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220902211058.60789-5-alexei.starovoitov@gmail.com --- samples/bpf/map_perf_test_kern.c | 44 ++++++++++++++++++++------------ samples/bpf/map_perf_test_user.c | 2 +- 2 files changed, 29 insertions(+), 17 deletions(-) diff --git a/samples/bpf/map_perf_test_kern.c b/samples/bpf/map_perf_test_kern.c index 8773f22b6a98..7342c5b2f278 100644 --- a/samples/bpf/map_perf_test_kern.c +++ b/samples/bpf/map_perf_test_kern.c @@ -108,11 +108,14 @@ int stress_hmap(struct pt_regs *ctx) u32 key = bpf_get_current_pid_tgid(); long init_val = 1; long *value; + int i; - bpf_map_update_elem(&hash_map, &key, &init_val, BPF_ANY); - value = bpf_map_lookup_elem(&hash_map, &key); - if (value) - bpf_map_delete_elem(&hash_map, &key); + for (i = 0; i < 10; i++) { + bpf_map_update_elem(&hash_map, &key, &init_val, BPF_ANY); + value = bpf_map_lookup_elem(&hash_map, &key); + if (value) + bpf_map_delete_elem(&hash_map, &key); + } return 0; } @@ -123,11 +126,14 @@ int stress_percpu_hmap(struct pt_regs *ctx) u32 key = bpf_get_current_pid_tgid(); long init_val = 1; long *value; + int i; - bpf_map_update_elem(&percpu_hash_map, &key, &init_val, BPF_ANY); - value = bpf_map_lookup_elem(&percpu_hash_map, &key); - if (value) - bpf_map_delete_elem(&percpu_hash_map, &key); + for (i = 0; i < 10; i++) { + bpf_map_update_elem(&percpu_hash_map, &key, &init_val, BPF_ANY); + value = bpf_map_lookup_elem(&percpu_hash_map, &key); + if (value) + bpf_map_delete_elem(&percpu_hash_map, &key); + } return 0; } @@ -137,11 +143,14 @@ int stress_hmap_alloc(struct pt_regs *ctx) u32 key = bpf_get_current_pid_tgid(); long init_val = 1; long *value; + int i; - bpf_map_update_elem(&hash_map_alloc, &key, &init_val, BPF_ANY); - value = bpf_map_lookup_elem(&hash_map_alloc, &key); - if (value) - bpf_map_delete_elem(&hash_map_alloc, &key); + for (i = 0; i < 10; i++) { + bpf_map_update_elem(&hash_map_alloc, &key, &init_val, BPF_ANY); + value = bpf_map_lookup_elem(&hash_map_alloc, &key); + if (value) + bpf_map_delete_elem(&hash_map_alloc, &key); + } return 0; } @@ -151,11 +160,14 @@ int stress_percpu_hmap_alloc(struct pt_regs *ctx) u32 key = bpf_get_current_pid_tgid(); long init_val = 1; long *value; + int i; - bpf_map_update_elem(&percpu_hash_map_alloc, &key, &init_val, BPF_ANY); - value = bpf_map_lookup_elem(&percpu_hash_map_alloc, &key); - if (value) - bpf_map_delete_elem(&percpu_hash_map_alloc, &key); + for (i = 0; i < 10; i++) { + bpf_map_update_elem(&percpu_hash_map_alloc, &key, &init_val, BPF_ANY); + value = bpf_map_lookup_elem(&percpu_hash_map_alloc, &key); + if (value) + bpf_map_delete_elem(&percpu_hash_map_alloc, &key); + } return 0; } diff --git a/samples/bpf/map_perf_test_user.c b/samples/bpf/map_perf_test_user.c index b6fc174ab1f2..1bb53f4b29e1 100644 --- a/samples/bpf/map_perf_test_user.c +++ b/samples/bpf/map_perf_test_user.c @@ -72,7 +72,7 @@ static int test_flags = ~0; static uint32_t num_map_entries; static uint32_t inner_lru_hash_size; static int lru_hash_lookup_test_entries = 32; -static uint32_t max_cnt = 1000000; +static uint32_t max_cnt = 10000; static int check_test_flags(enum test_type t) {