samples/bpf/tracex3_user.c

Source file repositories/reference/linux-study-clean/samples/bpf/tracex3_user.c

File Facts

System
Linux kernel
Corpus path
samples/bpf/tracex3_user.c
Extension
.c
Size
3752 bytes
Lines
184
Domain
Support Tooling And Documentation
Bucket
samples
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

if (strcmp(argv[i], "-a") == 0) {
			full_range = true;
		} else if (strcmp(argv[i], "-t") == 0) {
			text_only = true;
		} else if (strcmp(argv[i], "-h") == 0) {
			printf("Usage:\n"
			       "  -a display wider latency range\n"
			       "  -t text only\n");
			return 1;
		}
	}

	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;
	}

	/* 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, "lat_map");
	if (map_fd < 0) {
		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
		goto cleanup;
	}

	bpf_object__for_each_program(prog, obj) {
		links[j] = bpf_program__attach(prog);
		if (libbpf_get_error(links[j])) {
			fprintf(stderr, "ERROR: bpf_program__attach failed\n");
			links[j] = NULL;
			goto cleanup;
		}
		j++;
	}

	printf("  heatmap of IO latency\n");
	if (text_only)
		printf("  %s", sym[num_colors - 1]);
	else
		printf("  %s %s", color[num_colors - 1], nocolor);
	printf(" - many events with this latency\n");

	if (text_only)
		printf("  %s", sym[0]);
	else
		printf("  %s %s", color[0], nocolor);
	printf(" - few events\n");

	for (i = 0; ; i++) {
		if (i % 20 == 0)
			print_banner();
		print_hist(map_fd);
		sleep(2);
	}

cleanup:
	for (j--; j >= 0; j--)
		bpf_link__destroy(links[j]);

	bpf_object__close(obj);
	return 0;
}

Annotation

Implementation Notes