diff options
Diffstat (limited to 'samples/bpf/trace_output_user.c')
| -rw-r--r-- | samples/bpf/trace_output_user.c | 191 |
1 files changed, 50 insertions, 141 deletions
diff --git a/samples/bpf/trace_output_user.c b/samples/bpf/trace_output_user.c index ccca1e348017..d316fd2c8e24 100644 --- a/samples/bpf/trace_output_user.c +++ b/samples/bpf/trace_output_user.c @@ -1,119 +1,10 @@ -/* This program is free software; you can redistribute it and/or - * modify it under the terms of version 2 of the GNU General Public - * License as published by the Free Software Foundation. - */ +// SPDX-License-Identifier: GPL-2.0-only #include <stdio.h> -#include <unistd.h> -#include <stdlib.h> -#include <stdbool.h> -#include <string.h> #include <fcntl.h> #include <poll.h> -#include <linux/perf_event.h> -#include <linux/bpf.h> -#include <errno.h> -#include <assert.h> -#include <sys/syscall.h> -#include <sys/ioctl.h> -#include <sys/mman.h> #include <time.h> #include <signal.h> -#include "libbpf.h" -#include "bpf_load.h" -#include "perf-sys.h" - -static int pmu_fd; - -int page_size; -int page_cnt = 8; -volatile struct perf_event_mmap_page *header; - -typedef void (*print_fn)(void *data, int size); - -static int perf_event_mmap(int fd) -{ - void *base; - int mmap_size; - - page_size = getpagesize(); - mmap_size = page_size * (page_cnt + 1); - - base = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); - if (base == MAP_FAILED) { - printf("mmap err\n"); - return -1; - } - - header = base; - return 0; -} - -static int perf_event_poll(int fd) -{ - struct pollfd pfd = { .fd = fd, .events = POLLIN }; - - return poll(&pfd, 1, 1000); -} - -struct perf_event_sample { - struct perf_event_header header; - __u32 size; - char data[]; -}; - -static void perf_event_read(print_fn fn) -{ - __u64 data_tail = header->data_tail; - __u64 data_head = header->data_head; - __u64 buffer_size = page_cnt * page_size; - void *base, *begin, *end; - char buf[256]; - - asm volatile("" ::: "memory"); /* in real code it should be smp_rmb() */ - if (data_head == data_tail) - return; - - base = ((char *)header) + page_size; - - begin = base + data_tail % buffer_size; - end = base + data_head % buffer_size; - - while (begin != end) { - struct perf_event_sample *e; - - e = begin; - if (begin + e->header.size > base + buffer_size) { - long len = base + buffer_size - begin; - - assert(len < e->header.size); - memcpy(buf, begin, len); - memcpy(buf + len, base, e->header.size - len); - e = (void *) buf; - begin = base + e->header.size - len; - } else if (begin + e->header.size == base + buffer_size) { - begin = base; - } else { - begin += e->header.size; - } - - if (e->header.type == PERF_RECORD_SAMPLE) { - fn(e->data, e->size); - } else if (e->header.type == PERF_RECORD_LOST) { - struct { - struct perf_event_header header; - __u64 id; - __u64 lost; - } *lost = (void *) e; - printf("lost %lld events\n", lost->lost); - } else { - printf("unknown event type=%d size=%d\n", - e->header.type, e->header.size); - } - } - - __sync_synchronize(); /* smp_mb() */ - header->data_tail = data_head; -} +#include <bpf/libbpf.h> static __u64 time_get_ns(void) { @@ -124,12 +15,12 @@ static __u64 time_get_ns(void) } static __u64 start_time; +static __u64 cnt; #define MAX_CNT 100000ll -static void print_bpf_output(void *data, int size) +static void print_bpf_output(void *ctx, int cpu, void *data, __u32 size) { - static __u64 cnt; struct { __u64 pid; __u64 cookie; @@ -138,7 +29,7 @@ static void print_bpf_output(void *data, int size) if (e->cookie != 0x12345678) { printf("BUG pid %llx cookie %llx sized %d\n", e->pid, e->cookie, size); - kill(0, SIGINT); + return; } cnt++; @@ -146,51 +37,69 @@ static void print_bpf_output(void *data, int size) if (cnt == MAX_CNT) { printf("recv %lld events per sec\n", MAX_CNT * 1000000000ll / (time_get_ns() - start_time)); - kill(0, SIGINT); + return; } } -static void test_bpf_perf_event(void) -{ - struct perf_event_attr attr = { - .sample_type = PERF_SAMPLE_RAW, - .type = PERF_TYPE_SOFTWARE, - .config = PERF_COUNT_SW_BPF_OUTPUT, - }; - int key = 0; - - pmu_fd = sys_perf_event_open(&attr, -1/*pid*/, 0/*cpu*/, -1/*group_fd*/, 0); - - assert(pmu_fd >= 0); - assert(bpf_map_update_elem(map_fd[0], &key, &pmu_fd, BPF_ANY) == 0); - ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0); -} - int main(int argc, char **argv) { + struct bpf_link *link = NULL; + struct bpf_program *prog; + struct perf_buffer *pb; + struct bpf_object *obj; + int map_fd, ret = 0; char filename[256]; FILE *f; - snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); + snprintf(filename, sizeof(filename), "%s.bpf.o", argv[0]); + obj = bpf_object__open_file(filename, NULL); + if (libbpf_get_error(obj)) { + fprintf(stderr, "ERROR: opening BPF object file failed\n"); + return 0; + } - if (load_bpf_file(filename)) { - printf("%s", bpf_log_buf); - return 1; + /* load BPF program */ + if (bpf_object__load(obj)) { + fprintf(stderr, "ERROR: loading BPF object file failed\n"); + goto cleanup; + } + + map_fd = bpf_object__find_map_fd_by_name(obj, "my_map"); + if (map_fd < 0) { + fprintf(stderr, "ERROR: finding a map in obj file failed\n"); + goto cleanup; } - test_bpf_perf_event(); + prog = bpf_object__find_program_by_name(obj, "bpf_prog1"); + if (libbpf_get_error(prog)) { + fprintf(stderr, "ERROR: finding a prog in obj file failed\n"); + goto cleanup; + } + + link = bpf_program__attach(prog); + if (libbpf_get_error(link)) { + fprintf(stderr, "ERROR: bpf_program__attach failed\n"); + link = NULL; + goto cleanup; + } - if (perf_event_mmap(pmu_fd) < 0) + pb = perf_buffer__new(map_fd, 8, print_bpf_output, NULL, NULL, NULL); + ret = libbpf_get_error(pb); + if (ret) { + printf("failed to setup perf_buffer: %d\n", ret); return 1; + } f = popen("taskset 1 dd if=/dev/zero of=/dev/null", "r"); (void) f; start_time = time_get_ns(); - for (;;) { - perf_event_poll(pmu_fd); - perf_event_read(print_bpf_output); + while ((ret = perf_buffer__poll(pb, 1000)) >= 0 && cnt < MAX_CNT) { } + kill(0, SIGINT); - return 0; +cleanup: + bpf_link__destroy(link); + bpf_object__close(obj); + return ret; } |