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>
diff --git a/samples/bpf/sampleip_kern.c b/samples/bpf/sampleip_kern.c
new file mode 100644
index 0000000..774a681
--- /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";