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author | Daniel Xu <dxu@dxuuu.xyz> | 2020-02-17 19:04:32 -0800 |
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committer | Alexei Starovoitov <ast@kernel.org> | 2020-02-19 15:01:07 -0800 |
commit | 67306f84ca78c2ca5136f21791710c126a55a19b (patch) | |
tree | 9017e0f53548a512619ec8dc4ffd13f2c5a37540 /tools/testing | |
parent | fff7b64355eac6e29b50229ad1512315bc04b44e (diff) | |
download | linux-stable-67306f84ca78c2ca5136f21791710c126a55a19b.tar.gz linux-stable-67306f84ca78c2ca5136f21791710c126a55a19b.tar.bz2 linux-stable-67306f84ca78c2ca5136f21791710c126a55a19b.zip |
selftests/bpf: Add bpf_read_branch_records() selftest
Add a selftest to test:
* default bpf_read_branch_records() behavior
* BPF_F_GET_BRANCH_RECORDS_SIZE flag behavior
* error path on non branch record perf events
* using helper to write to stack
* using helper to write to global
On host with hardware counter support:
# ./test_progs -t perf_branches
#27/1 perf_branches_hw:OK
#27/2 perf_branches_no_hw:OK
#27 perf_branches:OK
Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED
On host without hardware counter support (VM):
# ./test_progs -t perf_branches
#27/1 perf_branches_hw:OK
#27/2 perf_branches_no_hw:OK
#27 perf_branches:OK
Summary: 1/2 PASSED, 1 SKIPPED, 0 FAILED
Also sync tools/include/uapi/linux/bpf.h.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200218030432.4600-3-dxu@dxuuu.xyz
Diffstat (limited to 'tools/testing')
-rw-r--r-- | tools/testing/selftests/bpf/prog_tests/perf_branches.c | 170 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/progs/test_perf_branches.c | 50 |
2 files changed, 220 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/perf_branches.c b/tools/testing/selftests/bpf/prog_tests/perf_branches.c new file mode 100644 index 000000000000..e35c444902a7 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/perf_branches.c @@ -0,0 +1,170 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include <pthread.h> +#include <sched.h> +#include <sys/socket.h> +#include <test_progs.h> +#include "bpf/libbpf_internal.h" +#include "test_perf_branches.skel.h" + +static void check_good_sample(struct test_perf_branches *skel) +{ + int written_global = skel->bss->written_global_out; + int required_size = skel->bss->required_size_out; + int written_stack = skel->bss->written_stack_out; + int pbe_size = sizeof(struct perf_branch_entry); + int duration = 0; + + if (CHECK(!skel->bss->valid, "output not valid", + "no valid sample from prog")) + return; + + /* + * It's hard to validate the contents of the branch entries b/c it + * would require some kind of disassembler and also encoding the + * valid jump instructions for supported architectures. So just check + * the easy stuff for now. + */ + CHECK(required_size <= 0, "read_branches_size", "err %d\n", required_size); + CHECK(written_stack < 0, "read_branches_stack", "err %d\n", written_stack); + CHECK(written_stack % pbe_size != 0, "read_branches_stack", + "stack bytes written=%d not multiple of struct size=%d\n", + written_stack, pbe_size); + CHECK(written_global < 0, "read_branches_global", "err %d\n", written_global); + CHECK(written_global % pbe_size != 0, "read_branches_global", + "global bytes written=%d not multiple of struct size=%d\n", + written_global, pbe_size); + CHECK(written_global < written_stack, "read_branches_size", + "written_global=%d < written_stack=%d\n", written_global, written_stack); +} + +static void check_bad_sample(struct test_perf_branches *skel) +{ + int written_global = skel->bss->written_global_out; + int required_size = skel->bss->required_size_out; + int written_stack = skel->bss->written_stack_out; + int duration = 0; + + if (CHECK(!skel->bss->valid, "output not valid", + "no valid sample from prog")) + return; + + CHECK((required_size != -EINVAL && required_size != -ENOENT), + "read_branches_size", "err %d\n", required_size); + CHECK((written_stack != -EINVAL && written_stack != -ENOENT), + "read_branches_stack", "written %d\n", written_stack); + CHECK((written_global != -EINVAL && written_global != -ENOENT), + "read_branches_global", "written %d\n", written_global); +} + +static void test_perf_branches_common(int perf_fd, + void (*cb)(struct test_perf_branches *)) +{ + struct test_perf_branches *skel; + int err, i, duration = 0; + bool detached = false; + struct bpf_link *link; + volatile int j = 0; + cpu_set_t cpu_set; + + skel = test_perf_branches__open_and_load(); + if (CHECK(!skel, "test_perf_branches_load", + "perf_branches skeleton failed\n")) + return; + + /* attach perf_event */ + link = bpf_program__attach_perf_event(skel->progs.perf_branches, perf_fd); + if (CHECK(IS_ERR(link), "attach_perf_event", "err %ld\n", PTR_ERR(link))) + goto out_destroy_skel; + + /* generate some branches on cpu 0 */ + CPU_ZERO(&cpu_set); + CPU_SET(0, &cpu_set); + err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set), &cpu_set); + if (CHECK(err, "set_affinity", "cpu #0, err %d\n", err)) + goto out_destroy; + /* spin the loop for a while (random high number) */ + for (i = 0; i < 1000000; ++i) + ++j; + + test_perf_branches__detach(skel); + detached = true; + + cb(skel); +out_destroy: + bpf_link__destroy(link); +out_destroy_skel: + if (!detached) + test_perf_branches__detach(skel); + test_perf_branches__destroy(skel); +} + +static void test_perf_branches_hw(void) +{ + struct perf_event_attr attr = {0}; + int duration = 0; + int pfd; + + /* create perf event */ + attr.size = sizeof(attr); + attr.type = PERF_TYPE_HARDWARE; + attr.config = PERF_COUNT_HW_CPU_CYCLES; + attr.freq = 1; + attr.sample_freq = 4000; + attr.sample_type = PERF_SAMPLE_BRANCH_STACK; + attr.branch_sample_type = PERF_SAMPLE_BRANCH_USER | PERF_SAMPLE_BRANCH_ANY; + pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC); + + /* + * Some setups don't support branch records (virtual machines, !x86), + * so skip test in this case. + */ + if (pfd == -1) { + if (errno == ENOENT || errno == EOPNOTSUPP) { + printf("%s:SKIP:no PERF_SAMPLE_BRANCH_STACK\n", + __func__); + test__skip(); + return; + } + if (CHECK(pfd < 0, "perf_event_open", "err %d errno %d\n", + pfd, errno)) + return; + } + + test_perf_branches_common(pfd, check_good_sample); + + close(pfd); +} + +/* + * Tests negative case -- run bpf_read_branch_records() on improperly configured + * perf event. + */ +static void test_perf_branches_no_hw(void) +{ + struct perf_event_attr attr = {0}; + int duration = 0; + int pfd; + + /* create perf event */ + attr.size = sizeof(attr); + attr.type = PERF_TYPE_SOFTWARE; + attr.config = PERF_COUNT_SW_CPU_CLOCK; + attr.freq = 1; + attr.sample_freq = 4000; + pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC); + if (CHECK(pfd < 0, "perf_event_open", "err %d\n", pfd)) + return; + + test_perf_branches_common(pfd, check_bad_sample); + + close(pfd); +} + +void test_perf_branches(void) +{ + if (test__start_subtest("perf_branches_hw")) + test_perf_branches_hw(); + if (test__start_subtest("perf_branches_no_hw")) + test_perf_branches_no_hw(); +} diff --git a/tools/testing/selftests/bpf/progs/test_perf_branches.c b/tools/testing/selftests/bpf/progs/test_perf_branches.c new file mode 100644 index 000000000000..0f7e27d97567 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_perf_branches.c @@ -0,0 +1,50 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2019 Facebook + +#include <stddef.h> +#include <linux/ptrace.h> +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> +#include "bpf_trace_helpers.h" + +int valid = 0; +int required_size_out = 0; +int written_stack_out = 0; +int written_global_out = 0; + +struct { + __u64 _a; + __u64 _b; + __u64 _c; +} fpbe[30] = {0}; + +SEC("perf_event") +int perf_branches(void *ctx) +{ + __u64 entries[4 * 3] = {0}; + int required_size, written_stack, written_global; + + /* write to stack */ + written_stack = bpf_read_branch_records(ctx, entries, sizeof(entries), 0); + /* ignore spurious events */ + if (!written_stack) + return 1; + + /* get required size */ + required_size = bpf_read_branch_records(ctx, NULL, 0, + BPF_F_GET_BRANCH_RECORDS_SIZE); + + written_global = bpf_read_branch_records(ctx, fpbe, sizeof(fpbe), 0); + /* ignore spurious events */ + if (!written_global) + return 1; + + required_size_out = required_size; + written_stack_out = written_stack; + written_global_out = written_global; + valid = 1; + + return 0; +} + +char _license[] SEC("license") = "GPL"; |