From c17bec549c9dc969b4e725c56aa9ebb125378397 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 23 Jul 2019 14:34:44 -0700 Subject: [PATCH] samples/bpf: switch trace_output sample to perf_buffer API Convert trace_output sample to libbpf's perf_buffer API. Signed-off-by: Andrii Nakryiko Acked-by: Song Liu Signed-off-by: Alexei Starovoitov --- samples/bpf/trace_output_user.c | 43 +++++++++++---------------------- 1 file changed, 14 insertions(+), 29 deletions(-) diff --git a/samples/bpf/trace_output_user.c b/samples/bpf/trace_output_user.c index 2dd1d39b152a..8ee47699a870 100644 --- a/samples/bpf/trace_output_user.c +++ b/samples/bpf/trace_output_user.c @@ -18,9 +18,6 @@ #include #include "bpf_load.h" #include "perf-sys.h" -#include "trace_helpers.h" - -static int pmu_fd; static __u64 time_get_ns(void) { @@ -31,12 +28,12 @@ static __u64 time_get_ns(void) } static __u64 start_time; +static __u64 cnt; #define MAX_CNT 100000ll -static int 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; @@ -45,7 +42,7 @@ static int 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); - return LIBBPF_PERF_EVENT_ERROR; + return; } cnt++; @@ -53,30 +50,14 @@ static int 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)); - return LIBBPF_PERF_EVENT_DONE; + return; } - - return LIBBPF_PERF_EVENT_CONT; -} - -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 perf_buffer_opts pb_opts = {}; + struct perf_buffer *pb; char filename[256]; FILE *f; int ret; @@ -88,16 +69,20 @@ int main(int argc, char **argv) return 1; } - test_bpf_perf_event(); - - if (perf_event_mmap(pmu_fd) < 0) + pb_opts.sample_cb = print_bpf_output; + pb = perf_buffer__new(map_fd[0], 8, &pb_opts); + 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(); - ret = perf_event_poller(pmu_fd, print_bpf_output); + while ((ret = perf_buffer__poll(pb, 1000)) >= 0 && cnt < MAX_CNT) { + } kill(0, SIGINT); return ret; } -- 2.30.2