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0efdcefb00
Current method of checking pointer error is not user friendly. Especially the __must_check define makes this less intuitive. Since, libbpf has an API libbpf_get_error() which checks pointer error, this commit refactors existing pointer error check logic with libbpf. Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200516040608.1377876-2-danieltimlee@gmail.com
355 lines
7.9 KiB
C
355 lines
7.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2016 Facebook
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*/
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#include <stdio.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <stdbool.h>
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#include <string.h>
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#include <linux/perf_event.h>
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#include <linux/bpf.h>
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#include <signal.h>
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#include <errno.h>
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#include <sys/resource.h>
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#include <bpf/bpf.h>
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#include <bpf/libbpf.h>
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#include "perf-sys.h"
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#include "trace_helpers.h"
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#define SAMPLE_FREQ 50
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static int pid;
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/* counts, stackmap */
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static int map_fd[2];
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struct bpf_program *prog;
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static bool sys_read_seen, sys_write_seen;
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static void print_ksym(__u64 addr)
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{
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struct ksym *sym;
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if (!addr)
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return;
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sym = ksym_search(addr);
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if (!sym) {
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printf("ksym not found. Is kallsyms loaded?\n");
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return;
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}
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printf("%s;", sym->name);
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if (!strstr(sym->name, "sys_read"))
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sys_read_seen = true;
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else if (!strstr(sym->name, "sys_write"))
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sys_write_seen = true;
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}
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static void print_addr(__u64 addr)
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{
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if (!addr)
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return;
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printf("%llx;", addr);
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}
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#define TASK_COMM_LEN 16
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struct key_t {
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char comm[TASK_COMM_LEN];
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__u32 kernstack;
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__u32 userstack;
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};
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static void print_stack(struct key_t *key, __u64 count)
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{
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__u64 ip[PERF_MAX_STACK_DEPTH] = {};
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static bool warned;
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int i;
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printf("%3lld %s;", count, key->comm);
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if (bpf_map_lookup_elem(map_fd[1], &key->kernstack, ip) != 0) {
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printf("---;");
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} else {
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for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
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print_ksym(ip[i]);
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}
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printf("-;");
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if (bpf_map_lookup_elem(map_fd[1], &key->userstack, ip) != 0) {
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printf("---;");
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} else {
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for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
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print_addr(ip[i]);
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}
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if (count < 6)
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printf("\r");
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else
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printf("\n");
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if (key->kernstack == -EEXIST && !warned) {
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printf("stackmap collisions seen. Consider increasing size\n");
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warned = true;
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} else if ((int)key->kernstack < 0 && (int)key->userstack < 0) {
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printf("err stackid %d %d\n", key->kernstack, key->userstack);
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}
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}
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static void err_exit(int err)
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{
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kill(pid, SIGKILL);
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exit(err);
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}
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static void print_stacks(void)
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{
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struct key_t key = {}, next_key;
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__u64 value;
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__u32 stackid = 0, next_id;
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int error = 1, fd = map_fd[0], stack_map = map_fd[1];
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sys_read_seen = sys_write_seen = false;
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while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
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bpf_map_lookup_elem(fd, &next_key, &value);
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print_stack(&next_key, value);
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bpf_map_delete_elem(fd, &next_key);
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key = next_key;
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}
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printf("\n");
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if (!sys_read_seen || !sys_write_seen) {
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printf("BUG kernel stack doesn't contain sys_read() and sys_write()\n");
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err_exit(error);
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}
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/* clear stack map */
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while (bpf_map_get_next_key(stack_map, &stackid, &next_id) == 0) {
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bpf_map_delete_elem(stack_map, &next_id);
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stackid = next_id;
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}
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}
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static inline int generate_load(void)
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{
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if (system("dd if=/dev/zero of=/dev/null count=5000k status=none") < 0) {
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printf("failed to generate some load with dd: %s\n", strerror(errno));
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return -1;
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}
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return 0;
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}
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static void test_perf_event_all_cpu(struct perf_event_attr *attr)
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{
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int nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
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struct bpf_link **links = calloc(nr_cpus, sizeof(struct bpf_link *));
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int i, pmu_fd, error = 1;
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if (!links) {
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printf("malloc of links failed\n");
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goto err;
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}
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/* system wide perf event, no need to inherit */
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attr->inherit = 0;
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/* open perf_event on all cpus */
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for (i = 0; i < nr_cpus; i++) {
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pmu_fd = sys_perf_event_open(attr, -1, i, -1, 0);
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if (pmu_fd < 0) {
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printf("sys_perf_event_open failed\n");
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goto all_cpu_err;
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}
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links[i] = bpf_program__attach_perf_event(prog, pmu_fd);
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if (libbpf_get_error(links[i])) {
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printf("bpf_program__attach_perf_event failed\n");
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links[i] = NULL;
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close(pmu_fd);
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goto all_cpu_err;
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}
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}
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if (generate_load() < 0)
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goto all_cpu_err;
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print_stacks();
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error = 0;
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all_cpu_err:
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for (i--; i >= 0; i--)
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bpf_link__destroy(links[i]);
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err:
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free(links);
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if (error)
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err_exit(error);
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}
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static void test_perf_event_task(struct perf_event_attr *attr)
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{
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struct bpf_link *link = NULL;
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int pmu_fd, error = 1;
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/* per task perf event, enable inherit so the "dd ..." command can be traced properly.
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* Enabling inherit will cause bpf_perf_prog_read_time helper failure.
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*/
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attr->inherit = 1;
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/* open task bound event */
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pmu_fd = sys_perf_event_open(attr, 0, -1, -1, 0);
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if (pmu_fd < 0) {
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printf("sys_perf_event_open failed\n");
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goto err;
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}
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link = bpf_program__attach_perf_event(prog, pmu_fd);
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if (libbpf_get_error(link)) {
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printf("bpf_program__attach_perf_event failed\n");
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link = NULL;
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close(pmu_fd);
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goto err;
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}
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if (generate_load() < 0)
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goto err;
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print_stacks();
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error = 0;
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err:
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bpf_link__destroy(link);
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if (error)
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err_exit(error);
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}
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static void test_bpf_perf_event(void)
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{
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struct perf_event_attr attr_type_hw = {
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.sample_freq = SAMPLE_FREQ,
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.freq = 1,
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.type = PERF_TYPE_HARDWARE,
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.config = PERF_COUNT_HW_CPU_CYCLES,
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};
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struct perf_event_attr attr_type_sw = {
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.sample_freq = SAMPLE_FREQ,
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.freq = 1,
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.type = PERF_TYPE_SOFTWARE,
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.config = PERF_COUNT_SW_CPU_CLOCK,
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};
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struct perf_event_attr attr_hw_cache_l1d = {
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.sample_freq = SAMPLE_FREQ,
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.freq = 1,
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.type = PERF_TYPE_HW_CACHE,
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.config =
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PERF_COUNT_HW_CACHE_L1D |
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(PERF_COUNT_HW_CACHE_OP_READ << 8) |
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(PERF_COUNT_HW_CACHE_RESULT_ACCESS << 16),
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};
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struct perf_event_attr attr_hw_cache_branch_miss = {
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.sample_freq = SAMPLE_FREQ,
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.freq = 1,
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.type = PERF_TYPE_HW_CACHE,
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.config =
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PERF_COUNT_HW_CACHE_BPU |
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(PERF_COUNT_HW_CACHE_OP_READ << 8) |
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(PERF_COUNT_HW_CACHE_RESULT_MISS << 16),
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};
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struct perf_event_attr attr_type_raw = {
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.sample_freq = SAMPLE_FREQ,
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.freq = 1,
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.type = PERF_TYPE_RAW,
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/* Intel Instruction Retired */
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.config = 0xc0,
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};
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struct perf_event_attr attr_type_raw_lock_load = {
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.sample_freq = SAMPLE_FREQ,
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.freq = 1,
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.type = PERF_TYPE_RAW,
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/* Intel MEM_UOPS_RETIRED.LOCK_LOADS */
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.config = 0x21d0,
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/* Request to record lock address from PEBS */
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.sample_type = PERF_SAMPLE_ADDR,
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/* Record address value requires precise event */
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.precise_ip = 2,
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};
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printf("Test HW_CPU_CYCLES\n");
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test_perf_event_all_cpu(&attr_type_hw);
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test_perf_event_task(&attr_type_hw);
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printf("Test SW_CPU_CLOCK\n");
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test_perf_event_all_cpu(&attr_type_sw);
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test_perf_event_task(&attr_type_sw);
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printf("Test HW_CACHE_L1D\n");
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test_perf_event_all_cpu(&attr_hw_cache_l1d);
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test_perf_event_task(&attr_hw_cache_l1d);
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printf("Test HW_CACHE_BPU\n");
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test_perf_event_all_cpu(&attr_hw_cache_branch_miss);
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test_perf_event_task(&attr_hw_cache_branch_miss);
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printf("Test Instruction Retired\n");
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test_perf_event_all_cpu(&attr_type_raw);
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test_perf_event_task(&attr_type_raw);
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printf("Test Lock Load\n");
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test_perf_event_all_cpu(&attr_type_raw_lock_load);
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test_perf_event_task(&attr_type_raw_lock_load);
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printf("*** PASS ***\n");
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}
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int main(int argc, char **argv)
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{
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struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
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struct bpf_object *obj = NULL;
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char filename[256];
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int error = 1;
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snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
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setrlimit(RLIMIT_MEMLOCK, &r);
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signal(SIGINT, err_exit);
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signal(SIGTERM, err_exit);
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if (load_kallsyms()) {
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printf("failed to process /proc/kallsyms\n");
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goto cleanup;
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}
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obj = bpf_object__open_file(filename, NULL);
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if (libbpf_get_error(obj)) {
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printf("opening BPF object file failed\n");
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obj = NULL;
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goto cleanup;
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}
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prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
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if (!prog) {
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printf("finding a prog in obj file failed\n");
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goto cleanup;
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}
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/* load BPF program */
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if (bpf_object__load(obj)) {
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printf("loading BPF object file failed\n");
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goto cleanup;
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}
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map_fd[0] = bpf_object__find_map_fd_by_name(obj, "counts");
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map_fd[1] = bpf_object__find_map_fd_by_name(obj, "stackmap");
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if (map_fd[0] < 0 || map_fd[1] < 0) {
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printf("finding a counts/stackmap map in obj file failed\n");
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goto cleanup;
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}
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pid = fork();
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if (pid == 0) {
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read_trace_pipe();
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return 0;
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} else if (pid == -1) {
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printf("couldn't spawn process\n");
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goto cleanup;
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}
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test_bpf_perf_event();
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error = 0;
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cleanup:
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bpf_object__close(obj);
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err_exit(error);
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}
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