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author | Brendan Gregg <bgregg@netflix.com> | 2016-09-01 18:37:26 -0700 |
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committer | David S. Miller <davem@davemloft.net> | 2016-09-02 10:46:45 -0700 |
commit | 72874418e4b9e2673c26a810b0ae9f418b573ee3 (patch) | |
tree | ce7e1ec61c8c12ef2b02ac5bb67b6ed8d2023f64 /samples/bpf/sampleip_kern.c | |
parent | 1c47910ef80135ac89e4d0b471d123572cee5535 (diff) | |
download | linux-72874418e4b9e2673c26a810b0ae9f418b573ee3.tar.bz2 |
samples/bpf: add sampleip example
sample instruction pointer and frequency count in a BPF map
Signed-off-by: Brendan Gregg <bgregg@netflix.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'samples/bpf/sampleip_kern.c')
-rw-r--r-- | samples/bpf/sampleip_kern.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/samples/bpf/sampleip_kern.c b/samples/bpf/sampleip_kern.c new file mode 100644 index 000000000000..774a681f374a --- /dev/null +++ b/samples/bpf/sampleip_kern.c @@ -0,0 +1,38 @@ +/* Copyright 2016 Netflix, Inc. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + */ +#include <linux/version.h> +#include <linux/ptrace.h> +#include <uapi/linux/bpf.h> +#include <uapi/linux/bpf_perf_event.h> +#include "bpf_helpers.h" + +#define MAX_IPS 8192 + +struct bpf_map_def SEC("maps") ip_map = { + .type = BPF_MAP_TYPE_HASH, + .key_size = sizeof(u64), + .value_size = sizeof(u32), + .max_entries = MAX_IPS, +}; + +SEC("perf_event") +int do_sample(struct bpf_perf_event_data *ctx) +{ + u64 ip; + u32 *value, init_val = 1; + + ip = ctx->regs.ip; + value = bpf_map_lookup_elem(&ip_map, &ip); + if (value) + *value += 1; + else + /* E2BIG not tested for this example only */ + bpf_map_update_elem(&ip_map, &ip, &init_val, BPF_NOEXIST); + + return 0; +} +char _license[] SEC("license") = "GPL"; |