[PATCH 8/9] sample/bpf: sockex1: user percpu array map
From: Ming Lei <tom.leiming@gmail.com>
Date: 2016-01-11 15:58:34
Also in:
lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
It is demonstrated the expensive atomic operations can be removed in eBPF prog. Signed-off-by: Ming Lei <tom.leiming@gmail.com> --- samples/bpf/sockex1_kern.c | 7 ++++--- samples/bpf/sockex1_user.c | 20 ++++++++++++++++---- 2 files changed, 20 insertions(+), 7 deletions(-)
diff --git a/samples/bpf/sockex1_kern.c b/samples/bpf/sockex1_kern.c
index ed18e9a..400518a 100644
--- a/samples/bpf/sockex1_kern.c
+++ b/samples/bpf/sockex1_kern.c@@ -5,7 +5,7 @@ #include "bpf_helpers.h" struct bpf_map_def SEC("maps") my_map = { - .type = BPF_MAP_TYPE_ARRAY, + .type = BPF_MAP_TYPE_ARRAY_PERCPU, .key_size = sizeof(u32), .value_size = sizeof(long), .max_entries = 256,
@@ -16,13 +16,14 @@ int bpf_prog1(struct __sk_buff *skb) { int index = load_byte(skb, ETH_HLEN + offsetof(struct iphdr, protocol)); long *value; + unsigned cpu = bpf_get_smp_processor_id(); if (skb->pkt_type != PACKET_OUTGOING) return 0; - value = bpf_map_lookup_elem(&my_map, &index); + value = bpf_map_lookup_elem_percpu(&my_map, &index, cpu); if (value) - __sync_fetch_and_add(value, skb->len); + *value += skb->len; return 0; }
diff --git a/samples/bpf/sockex1_user.c b/samples/bpf/sockex1_user.c
index 678ce46..8572e81 100644
--- a/samples/bpf/sockex1_user.c
+++ b/samples/bpf/sockex1_user.c@@ -6,6 +6,14 @@ #include <unistd.h> #include <arpa/inet.h> +static int handle_one_cpu(unsigned cpu, void *val_cpu, void *val) +{ + long long *cnt = val; + + *cnt += *(long *)val_cpu; + return 0; +} + int main(int ac, char **argv) { char filename[256];
@@ -28,17 +36,21 @@ int main(int ac, char **argv) (void) f; for (i = 0; i < 5; i++) { - long long tcp_cnt, udp_cnt, icmp_cnt; + long cnt_percpu; + long long tcp_cnt = 0, udp_cnt = 0, icmp_cnt = 0; int key; key = IPPROTO_TCP; - assert(bpf_lookup_elem(map_fd[0], &key, &tcp_cnt) == 0); + assert(bpf_lookup_elem_allcpu(map_fd[0], &key, + &cnt_percpu, &tcp_cnt, handle_one_cpu) == 0); key = IPPROTO_UDP; - assert(bpf_lookup_elem(map_fd[0], &key, &udp_cnt) == 0); + assert(bpf_lookup_elem_allcpu(map_fd[0], &key, + &cnt_percpu, &udp_cnt, handle_one_cpu) == 0); key = IPPROTO_ICMP; - assert(bpf_lookup_elem(map_fd[0], &key, &icmp_cnt) == 0); + assert(bpf_lookup_elem_allcpu(map_fd[0], &key, + &cnt_percpu, &icmp_cnt, handle_one_cpu) == 0); printf("TCP %lld UDP %lld ICMP %lld bytes\n", tcp_cnt, udp_cnt, icmp_cnt);
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1.9.1