diff options
Diffstat (limited to '')
-rw-r--r-- | tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c b/tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c new file mode 100644 index 000000000..3948da12a --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c @@ -0,0 +1,130 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ +#include <test_progs.h> +#include "get_branch_snapshot.skel.h" + +static int *pfd_array; +static int cpu_cnt; + +static bool is_hypervisor(void) +{ + char *line = NULL; + bool ret = false; + size_t len; + FILE *fp; + + fp = fopen("/proc/cpuinfo", "r"); + if (!fp) + return false; + + while (getline(&line, &len, fp) != -1) { + if (!strncmp(line, "flags", 5)) { + if (strstr(line, "hypervisor") != NULL) + ret = true; + break; + } + } + + free(line); + fclose(fp); + return ret; +} + +static int create_perf_events(void) +{ + struct perf_event_attr attr = {0}; + int cpu; + + /* create perf event */ + attr.size = sizeof(attr); + attr.type = PERF_TYPE_RAW; + attr.config = 0x1b00; + attr.sample_type = PERF_SAMPLE_BRANCH_STACK; + attr.branch_sample_type = PERF_SAMPLE_BRANCH_KERNEL | + PERF_SAMPLE_BRANCH_USER | PERF_SAMPLE_BRANCH_ANY; + + cpu_cnt = libbpf_num_possible_cpus(); + pfd_array = malloc(sizeof(int) * cpu_cnt); + if (!pfd_array) { + cpu_cnt = 0; + return 1; + } + + for (cpu = 0; cpu < cpu_cnt; cpu++) { + pfd_array[cpu] = syscall(__NR_perf_event_open, &attr, + -1, cpu, -1, PERF_FLAG_FD_CLOEXEC); + if (pfd_array[cpu] < 0) + break; + } + + return cpu == 0; +} + +static void close_perf_events(void) +{ + int cpu, fd; + + for (cpu = 0; cpu < cpu_cnt; cpu++) { + fd = pfd_array[cpu]; + if (fd < 0) + break; + close(fd); + } + free(pfd_array); +} + +void serial_test_get_branch_snapshot(void) +{ + struct get_branch_snapshot *skel = NULL; + int err; + + /* Skip the test before we fix LBR snapshot for hypervisor. */ + if (is_hypervisor()) { + test__skip(); + return; + } + + if (create_perf_events()) { + test__skip(); /* system doesn't support LBR */ + goto cleanup; + } + + skel = get_branch_snapshot__open_and_load(); + if (!ASSERT_OK_PTR(skel, "get_branch_snapshot__open_and_load")) + goto cleanup; + + err = kallsyms_find("bpf_testmod_loop_test", &skel->bss->address_low); + if (!ASSERT_OK(err, "kallsyms_find")) + goto cleanup; + + /* Just a guess for the end of this function, as module functions + * in /proc/kallsyms could come in any order. + */ + skel->bss->address_high = skel->bss->address_low + 128; + + err = get_branch_snapshot__attach(skel); + if (!ASSERT_OK(err, "get_branch_snapshot__attach")) + goto cleanup; + + trigger_module_test_read(100); + + if (skel->bss->total_entries < 16) { + /* too few entries for the hit/waste test */ + test__skip(); + goto cleanup; + } + + ASSERT_GT(skel->bss->test1_hits, 6, "find_looptest_in_lbr"); + + /* Given we stop LBR in software, we will waste a few entries. + * But we should try to waste as few as possible entries. We are at + * about 7 on x86_64 systems. + * Add a check for < 10 so that we get heads-up when something + * changes and wastes too many entries. + */ + ASSERT_LT(skel->bss->wasted_entries, 10, "check_wasted_entries"); + +cleanup: + get_branch_snapshot__destroy(skel); + close_perf_events(); +} |