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linux-next/samples/bpf/sampleip_kern.c
Brendan Gregg 72874418e4 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>
2016-09-02 10:46:45 -07:00

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914 B
C

/* 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";