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 <andriin@fb.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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@ -18,9 +18,6 @@
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#include <libbpf.h>
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#include "bpf_load.h"
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#include "perf-sys.h"
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#include "trace_helpers.h"
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static int pmu_fd;
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static __u64 time_get_ns(void)
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{
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@ -31,12 +28,12 @@ static __u64 time_get_ns(void)
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}
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static __u64 start_time;
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static __u64 cnt;
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#define MAX_CNT 100000ll
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static int print_bpf_output(void *data, int size)
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static void print_bpf_output(void *ctx, int cpu, void *data, __u32 size)
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{
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static __u64 cnt;
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struct {
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__u64 pid;
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__u64 cookie;
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@ -45,7 +42,7 @@ static int print_bpf_output(void *data, int size)
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if (e->cookie != 0x12345678) {
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printf("BUG pid %llx cookie %llx sized %d\n",
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e->pid, e->cookie, size);
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return LIBBPF_PERF_EVENT_ERROR;
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return;
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}
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cnt++;
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@ -53,30 +50,14 @@ static int print_bpf_output(void *data, int size)
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if (cnt == MAX_CNT) {
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printf("recv %lld events per sec\n",
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MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
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return LIBBPF_PERF_EVENT_DONE;
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return;
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}
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return LIBBPF_PERF_EVENT_CONT;
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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 = {
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.sample_type = PERF_SAMPLE_RAW,
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.type = PERF_TYPE_SOFTWARE,
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.config = PERF_COUNT_SW_BPF_OUTPUT,
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};
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int key = 0;
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pmu_fd = sys_perf_event_open(&attr, -1/*pid*/, 0/*cpu*/, -1/*group_fd*/, 0);
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assert(pmu_fd >= 0);
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assert(bpf_map_update_elem(map_fd[0], &key, &pmu_fd, BPF_ANY) == 0);
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ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
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}
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int main(int argc, char **argv)
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{
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struct perf_buffer_opts pb_opts = {};
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struct perf_buffer *pb;
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char filename[256];
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FILE *f;
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int ret;
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@ -88,16 +69,20 @@ int main(int argc, char **argv)
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return 1;
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}
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test_bpf_perf_event();
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if (perf_event_mmap(pmu_fd) < 0)
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pb_opts.sample_cb = print_bpf_output;
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pb = perf_buffer__new(map_fd[0], 8, &pb_opts);
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ret = libbpf_get_error(pb);
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if (ret) {
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printf("failed to setup perf_buffer: %d\n", ret);
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return 1;
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}
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f = popen("taskset 1 dd if=/dev/zero of=/dev/null", "r");
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(void) f;
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start_time = time_get_ns();
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ret = perf_event_poller(pmu_fd, print_bpf_output);
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while ((ret = perf_buffer__poll(pb, 1000)) >= 0 && cnt < MAX_CNT) {
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}
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kill(0, SIGINT);
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return ret;
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}
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