[PATCH bpf-next 5/5] selftests/bpf: add benchmark for uprobe vs. user_prog

[Song Liu]

Add a benchmark to compare performance of
  1) uprobe;
  2) user program w/o args;
  3) user program w/ args;
  4) user program w/ args on random cpu.

Sample output:

./test_progs -t uprobe_vs_user_prog -v
test_uprobe_vs_user_prog:PASS:uprobe_vs_user_prog__open_and_load 0 nsec
test_uprobe_vs_user_prog:PASS:get_base_addr 0 nsec
test_uprobe_vs_user_prog:PASS:attach_uprobe 0 nsec
run_perf_test:PASS:uprobe 0 nsec
Each uprobe uses 1419 nanoseconds
run_perf_test:PASS:user_prog_no_args 0 nsec
Each user_prog_no_args uses 313 nanoseconds
run_perf_test:PASS:user_prog_with_args 0 nsec
Each user_prog_with_args uses 335 nanoseconds
run_perf_test:PASS:user_prog_with_args_on_cpu 0 nsec
Each user_prog_with_args_on_cpu uses 2821 nanoseconds
Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Song Liu <songliubraving@xxxxxx>
---
 .../bpf/prog_tests/uprobe_vs_user_prog.c      | 101 ++++++++++++++++++
 .../selftests/bpf/progs/uprobe_vs_user_prog.c |  21 ++++
 2 files changed, 122 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/uprobe_vs_user_prog.c
 create mode 100644 tools/testing/selftests/bpf/progs/uprobe_vs_user_prog.c

diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_vs_user_prog.c b/tools/testing/selftests/bpf/prog_tests/uprobe_vs_user_prog.c
new file mode 100644
index 0000000000000..dadd7b56e69ec
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/uprobe_vs_user_prog.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include "uprobe_vs_user_prog.skel.h"
+
+#define REPEAT_CNT 10000ULL
+
+static int duration;
+
+static noinline void uprobe_target(void)
+{
+	asm ("");
+}
+
+struct bpf_prog_test_run_attr attr;
+
+static void call_user_prog(void)
+{
+	bpf_prog_test_run_xattr(&attr);
+}
+
+static int numcpu;
+
+static void call_user_prog_on_cpu(void)
+{
+	static int cpu = 0;
+
+	attr.cpu_plus = cpu + 1;
+	bpf_prog_test_run_xattr(&attr);
+	cpu = (cpu + 1) % numcpu;
+}
+
+typedef void (__run_func)(void);
+
+static void run_perf_test(struct uprobe_vs_user_prog *skel,
+			  __run_func func, const char *name)
+{
+	__u64 start_time, total_time;
+	int i;
+
+	skel->bss->sum = 0;
+
+	start_time = time_get_ns();
+	for (i = 0; i < REPEAT_CNT; i++)
+		func();
+	total_time = time_get_ns() - start_time;
+
+	CHECK(skel->bss->sum != REPEAT_CNT, name,
+	      "missed %llu times\n", REPEAT_CNT - skel->bss->sum);
+	printf("Each %s uses %llu nanoseconds\n", name, total_time / REPEAT_CNT);
+}
+
+void test_uprobe_vs_user_prog(void)
+{
+	struct bpf_user_prog_args args = {};
+	struct uprobe_vs_user_prog *skel;
+	struct bpf_link *uprobe_link;
+	size_t uprobe_offset;
+	ssize_t base_addr;
+
+	skel = uprobe_vs_user_prog__open_and_load();
+
+	if (CHECK(!skel, "uprobe_vs_user_prog__open_and_load",
+		  "skeleton open_and_laod failed\n"))
+		return;
+
+	base_addr = get_base_addr();
+	if (CHECK(base_addr < 0, "get_base_addr",
+		  "failed to find base addr: %zd", base_addr))
+		return;
+	uprobe_offset = (size_t)&uprobe_target - base_addr;
+	uprobe_link = bpf_program__attach_uprobe(skel->progs.handle_uprobe,
+						 false /* retprobe */,
+						 0 /* self pid */,
+						 "/proc/self/exe",
+						 uprobe_offset);
+
+	if (CHECK(IS_ERR(uprobe_link), "attach_uprobe",
+		  "err %ld\n", PTR_ERR(uprobe_link)))
+		goto cleanup;
+	skel->links.handle_uprobe = uprobe_link;
+
+	run_perf_test(skel, uprobe_target, "uprobe");
+
+	attr.prog_fd = bpf_program__fd(skel->progs.user_prog);
+	run_perf_test(skel, call_user_prog, "user_prog_no_args");
+
+	attr.data_size_in = sizeof(args);
+	attr.data_in = &args;
+	run_perf_test(skel, call_user_prog, "user_prog_with_args");
+
+	numcpu = libbpf_num_possible_cpus();
+
+	if (numcpu <= 0)
+		goto cleanup;
+
+	run_perf_test(skel, call_user_prog_on_cpu,
+		      "user_prog_with_args_on_cpu");
+
+cleanup:
+	uprobe_vs_user_prog__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/uprobe_vs_user_prog.c b/tools/testing/selftests/bpf/progs/uprobe_vs_user_prog.c
new file mode 100644
index 0000000000000..8b327b7cee30d
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/uprobe_vs_user_prog.c
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2017 Facebook
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+volatile __u64 sum = 0;
+
+SEC("uprobe/func")
+int handle_uprobe(struct pt_regs *ctx)
+{
+	sum++;
+	return 0;
+}
+
+SEC("user")
+int user_prog(struct pt_regs *ctx)
+{
+	sum++;
+	return 0;
+}
-- 
2.24.1