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linux/samples/bpf/trace_output_kern.c
Alexei Starovoitov 39111695b1 samples: bpf: add bpf_perf_event_output example
Performance test and example of bpf_perf_event_output().
kprobe is attached to sys_write() and trivial bpf program streams
pid+cookie into userspace via PERF_COUNT_SW_BPF_OUTPUT event.

Usage:
$ sudo ./bld_x64/samples/bpf/trace_output
recv 2968913 events per sec

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-10-22 06:42:15 -07:00

32 lines
642 B
C

#include <linux/ptrace.h>
#include <linux/version.h>
#include <uapi/linux/bpf.h>
#include "bpf_helpers.h"
struct bpf_map_def SEC("maps") my_map = {
.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
.key_size = sizeof(int),
.value_size = sizeof(u32),
.max_entries = 2,
};
SEC("kprobe/sys_write")
int bpf_prog1(struct pt_regs *ctx)
{
struct S {
u64 pid;
u64 cookie;
} data;
memset(&data, 0, sizeof(data));
data.pid = bpf_get_current_pid_tgid();
data.cookie = 0x12345678;
bpf_perf_event_output(ctx, &my_map, 0, &data, sizeof(data));
return 0;
}
char _license[] SEC("license") = "GPL";
u32 _version SEC("version") = LINUX_VERSION_CODE;