From 47efb30274cbec1bd3c0c980a7ece328df2c16a8 Mon Sep 17 00:00:00 2001
From: Kaixu Xia <xiakaixu@huawei.com>
Date: Thu, 6 Aug 2015 07:02:36 +0000
Subject: samples/bpf: example of get selected PMU counter value
This is a simple example and shows how to use the new ability
to get the selected Hardware PMU counter value.
Signed-off-by: Kaixu Xia <xiakaixu@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
samples/bpf/tracex6_kern.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
create mode 100644 samples/bpf/tracex6_kern.c
(limited to 'samples/bpf/tracex6_kern.c')
diff --git a/samples/bpf/tracex6_kern.c b/samples/bpf/tracex6_kern.c
new file mode 100644
index 000000000000..23d1cffaf249
--- /dev/null
+++ b/samples/bpf/tracex6_kern.c
@@ -0,0 +1,26 @@
+#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 = 32,
+};
+
+SEC("kprobe/sys_write")
+int bpf_prog1(struct pt_regs *ctx)
+{
+ u64 count;
+ u32 key = bpf_get_smp_processor_id();
+ char fmt[] = "CPU-%d %llu\n";
+
+ count = bpf_perf_event_read(&my_map, key);
+ bpf_trace_printk(fmt, sizeof(fmt), key, count);
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
+u32 _version SEC("version") = LINUX_VERSION_CODE;
--
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