diff mbox series

[v7,bpf-next,3/3] bpf: add selftest for BPF_ENABLE_STATS

Message ID 20200429035841.3959159-4-songliubraving@fb.com
State Changes Requested
Delegated to: BPF Maintainers
Headers show
Series bpf: sharing bpf runtime stats with | expand

Commit Message

Song Liu April 29, 2020, 3:58 a.m. UTC 
Add test for BPF_ENABLE_STATS, which should enable run_time_ns stats.

~/selftests/bpf# ./test_progs -t enable_stats  -v
test_enable_stats:PASS:skel_open_and_load 0 nsec
test_enable_stats:PASS:get_stats_fd 0 nsec
test_enable_stats:PASS:attach_raw_tp 0 nsec
test_enable_stats:PASS:get_prog_info 0 nsec
test_enable_stats:PASS:check_stats_enabled 0 nsec
test_enable_stats:PASS:map_lookup_elem 0 nsec
test_enable_stats:PASS:check_run_cnt_valid 0 nsec
Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Song Liu <songliubraving@fb.com>
---
 .../selftests/bpf/prog_tests/enable_stats.c   | 58 +++++++++++++++++++
 .../selftests/bpf/progs/test_enable_stats.c   | 18 ++++++
 2 files changed, 76 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/enable_stats.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_enable_stats.c

Comments

Alexei Starovoitov April 29, 2020, 4:57 a.m. UTC | #1 
On Tue, Apr 28, 2020 at 08:58:41PM -0700, Song Liu wrote:
> +
> +	skel = test_enable_stats__open_and_load();
> +	if (CHECK(!skel, "skel_open_and_load", "skeleton open/load failed\n"))
> +		return;
> +
> +	stats_fd = bpf_enable_stats(BPF_STATS_RUNTIME_CNT);

Just realized that the name is wrong.
The stats are enabling run_cnt and run_time_ns.
runtime_cnt sounds like 'snark' from 'The Hunting of the Snark' :)
May be BPF_STATS_RUN_TIME ?

> +	if (CHECK(stats_fd < 0, "get_stats_fd", "failed %d\n", errno)) {
> +		test_enable_stats__destroy(skel);
> +		return;
> +	}
> +
> +	err = test_enable_stats__attach(skel);
> +	if (CHECK(err, "attach_raw_tp", "err %d\n", err))
> +		goto cleanup;
> +
> +	/* generate 100 sys_enter */
> +	for (i = 0; i < 100; i++)
> +		usleep(1);
> +
> +	test_enable_stats__detach(skel);
> +
> +	prog_fd = bpf_program__fd(skel->progs.test_enable_stats);
> +	memset(&info, 0, info_len);
> +	err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
> +	if (CHECK(err, "get_prog_info",
> +		  "failed to get bpf_prog_info for fd %d\n", prog_fd))
> +		goto cleanup;
> +	if (CHECK(info.run_time_ns == 0, "check_stats_enabled",
> +		  "failed to enable run_time_ns stats\n"))
> +		goto cleanup;
> +
> +	bss_fd = bpf_map__fd(skel->maps.bss);
> +	err = bpf_map_lookup_elem(bss_fd, &zero, &count);

'count' is a global var. It's accessible directly via skeleton.
No need for map_lookup.
Even after __detach(skel) the global data is still valid.

> +	if (CHECK(err, "map_lookup_elem",
> +		  "failed map_lookup_elem for fd %d\n", bss_fd))
> +		goto cleanup;
> +
> +	CHECK(info.run_cnt != count, "check_run_cnt_valid",
> +	      "invalid run_cnt stats\n");

what happens if there are other syscalls during for(i<100) loop?
The count will still match, right?
Then why 100 ? and why usleep() at all?
test_enable_stats__attach() will generate at least one syscall.

> +
> +cleanup:
> +	test_enable_stats__destroy(skel);
> +	close(stats_fd);

May be close(stats_fd) first.
Then test_enable_stats__attach(skel); again.
Generate few more syscalls and check that 'count' incrementing,
but info.run_cnt doesnt ?
That check assumes that sysctl is off. Overkill?
Song Liu April 29, 2020, 5:32 a.m. UTC | #2 
> On Apr 28, 2020, at 9:57 PM, Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
> 
> On Tue, Apr 28, 2020 at 08:58:41PM -0700, Song Liu wrote:
>> +
>> +	skel = test_enable_stats__open_and_load();
>> +	if (CHECK(!skel, "skel_open_and_load", "skeleton open/load failed\n"))
>> +		return;
>> +
>> +	stats_fd = bpf_enable_stats(BPF_STATS_RUNTIME_CNT);
> 
> Just realized that the name is wrong.
> The stats are enabling run_cnt and run_time_ns.
> runtime_cnt sounds like 'snark' from 'The Hunting of the Snark' :)
> May be BPF_STATS_RUN_TIME ?

Will fix. 

[...]

>> +
>> +	CHECK(info.run_cnt != count, "check_run_cnt_valid",
>> +	      "invalid run_cnt stats\n");
> 
> what happens if there are other syscalls during for(i<100) loop?
> The count will still match, right?
> Then why 100 ? and why usleep() at all?
> test_enable_stats__attach() will generate at least one syscall.

We don't really need usleep. I was thinking if it matches after 
many calls it really matches... I will remove it.

> 
>> +
>> +cleanup:
>> +	test_enable_stats__destroy(skel);
>> +	close(stats_fd);
> 
> May be close(stats_fd) first.
> Then test_enable_stats__attach(skel); again.
> Generate few more syscalls and check that 'count' incrementing,
> but info.run_cnt doesnt ?
> That check assumes that sysctl is off. Overkill?

I thought about this. However, close(stats_fd) cannot guarantee 
the stats is not enabled by other fd or the sysctl. I think this
will generate noise on specific systems. 

Thanks, 
Song
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/prog_tests/enable_stats.c b/tools/testing/selftests/bpf/prog_tests/enable_stats.c
new file mode 100644
index 000000000000..4930efe4cd2b
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/enable_stats.c
@@ -0,0 +1,58 @@ 
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include <sys/mman.h>
+#include "test_enable_stats.skel.h"
+
+void test_enable_stats(void)
+{
+	int stats_fd, err, prog_fd, bss_fd, i;
+	struct test_enable_stats *skel;
+	struct bpf_prog_info info;
+	__u32 info_len = sizeof(info);
+	int duration = 0;
+	__u32 zero = 0;
+	__u64 count;
+
+	skel = test_enable_stats__open_and_load();
+	if (CHECK(!skel, "skel_open_and_load", "skeleton open/load failed\n"))
+		return;
+
+	stats_fd = bpf_enable_stats(BPF_STATS_RUNTIME_CNT);
+	if (CHECK(stats_fd < 0, "get_stats_fd", "failed %d\n", errno)) {
+		test_enable_stats__destroy(skel);
+		return;
+	}
+
+	err = test_enable_stats__attach(skel);
+	if (CHECK(err, "attach_raw_tp", "err %d\n", err))
+		goto cleanup;
+
+	/* generate 100 sys_enter */
+	for (i = 0; i < 100; i++)
+		usleep(1);
+
+	test_enable_stats__detach(skel);
+
+	prog_fd = bpf_program__fd(skel->progs.test_enable_stats);
+	memset(&info, 0, info_len);
+	err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
+	if (CHECK(err, "get_prog_info",
+		  "failed to get bpf_prog_info for fd %d\n", prog_fd))
+		goto cleanup;
+	if (CHECK(info.run_time_ns == 0, "check_stats_enabled",
+		  "failed to enable run_time_ns stats\n"))
+		goto cleanup;
+
+	bss_fd = bpf_map__fd(skel->maps.bss);
+	err = bpf_map_lookup_elem(bss_fd, &zero, &count);
+	if (CHECK(err, "map_lookup_elem",
+		  "failed map_lookup_elem for fd %d\n", bss_fd))
+		goto cleanup;
+
+	CHECK(info.run_cnt != count, "check_run_cnt_valid",
+	      "invalid run_cnt stats\n");
+
+cleanup:
+	test_enable_stats__destroy(skel);
+	close(stats_fd);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_enable_stats.c b/tools/testing/selftests/bpf/progs/test_enable_stats.c
new file mode 100644
index 000000000000..dfd987e4ede4
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_enable_stats.c
@@ -0,0 +1,18 @@ 
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 Facebook
+
+#include <linux/bpf.h>
+#include <stdint.h>
+#include <linux/types.h>
+#include <bpf/bpf_helpers.h>
+
+char _license[] SEC("license") = "GPL";
+
+static __u64 count;
+
+SEC("raw_tracepoint/sys_enter")
+int test_enable_stats(void *ctx)
+{
+	count += 1;
+	return 0;
+}