samples/bpf: switch trace_output sample to perf_buffer API (c17bec54) · Commits · 戴 / test

samples/bpf/trace_output_user.c

+14 −29

Original line number	Diff line number	Diff line
		@@ -18,9 +18,6 @@
		#include <libbpf.h>
		#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;
		}

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