samples/bpf: add tests for more perf event types

$ trace_event

tests attaching BPF program to HW_CPU_CYCLES, SW_CPU_CLOCK, HW_CACHE_L1D and other events.
It runs 'dd' in the background while bpf program collects user and kernel
stack trace on counter overflow.
User space expects to see sys_read and sys_write in the kernel stack.

$ tracex6

tests reading of various perf counters from BPF program.

Both tests were refactored to increase coverage and be more accurate.

Signed-off-by: Teng Qin <qinteng@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 21 insertions, 7 deletions

diff --git a/samples/bpf/tracex6_kern.c b/samples/bpf/tracex6_kern.c
index be479c4af9e2..e7d180305974 100644
--- a/samples/bpf/tracex6_kern.c
+++ b/samples/bpf/tracex6_kern.c
@@ -3,22 +3,36 @@
 #include <uapi/linux/bpf.h>
 #include "bpf_helpers.h"
 
-struct bpf_map_def SEC("maps") my_map = {
+struct bpf_map_def SEC("maps") counters = {
 	.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
 	.key_size = sizeof(int),
 	.value_size = sizeof(u32),
-	.max_entries = 32,
+	.max_entries = 64,
+};
+struct bpf_map_def SEC("maps") values = {
+	.type = BPF_MAP_TYPE_HASH,
+	.key_size = sizeof(int),
+	.value_size = sizeof(u64),
+	.max_entries = 64,
 };
 
-SEC("kprobe/sys_write")
+SEC("kprobe/htab_map_get_next_key")
 int bpf_prog1(struct pt_regs *ctx)
 {
-	u64 count;
 	u32 key = bpf_get_smp_processor_id();
-	char fmt[] = "CPU-%d   %llu\n";
+	u64 count, *val;
+	s64 error;
+
+	count = bpf_perf_event_read(&counters, key);
+	error = (s64)count;
+	if (error <= -2 && error >= -22)
+		return 0;
 
-	count = bpf_perf_event_read(&my_map, key);
-	bpf_trace_printk(fmt, sizeof(fmt), key, count);
+	val = bpf_map_lookup_elem(&values, &key);
+	if (val)
+		*val = count;
+	else
+		bpf_map_update_elem(&values, &key, &count, BPF_NOEXIST);
 
 	return 0;
 }