tools/perf/util/tsc.c

Source file repositories/reference/linux-study-clean/tools/perf/util/tsc.c

File Facts

System
Linux kernel
Corpus path
tools/perf/util/tsc.c
Extension
.c
Size
3638 bytes
Lines
143
Domain
Support Tooling And Documentation
Bucket
tools
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 (++i > 10000) {
			pr_debug("failed to get perf_event_mmap_page lock\n");
			return -EINVAL;
		}
	}

	if (!tc->cap_user_time_zero)
		return -EOPNOTSUPP;

	return 0;
}

int perf_event__synth_time_conv(const struct perf_event_mmap_page *pc,
				const struct perf_tool *tool,
				perf_event__handler_t process,
				struct machine *machine)
{
	union perf_event event = {
		.time_conv = {
			.header = {
				.type = PERF_RECORD_TIME_CONV,
				.size = sizeof(struct perf_record_time_conv),
			},
		},
	};
	struct perf_tsc_conversion tc;
	int err;

	if (!pc)
		return 0;
	err = perf_read_tsc_conversion(pc, &tc);
	if (err == -EOPNOTSUPP)
		return 0;
	if (err)
		return err;

	pr_debug2("Synthesizing TSC conversion information\n");

	event.time_conv.time_mult  = tc.time_mult;
	event.time_conv.time_shift = tc.time_shift;
	event.time_conv.time_zero  = tc.time_zero;
	event.time_conv.time_cycles = tc.time_cycles;
	event.time_conv.time_mask = tc.time_mask;
	event.time_conv.cap_user_time_zero = tc.cap_user_time_zero;
	event.time_conv.cap_user_time_short = tc.cap_user_time_short;

	return process(tool, &event, NULL, machine);
}

u64 __weak rdtsc(void)
{
	return 0;
}

size_t perf_event__fprintf_time_conv(union perf_event *event, FILE *fp)
{
	struct perf_record_time_conv *tc = (struct perf_record_time_conv *)event;
	size_t ret;

	ret  = fprintf(fp, "\n... Time Shift      %" PRI_lu64 "\n", tc->time_shift);
	ret += fprintf(fp, "... Time Multiplier %" PRI_lu64 "\n", tc->time_mult);
	ret += fprintf(fp, "... Time Zero       %" PRI_lu64 "\n", tc->time_zero);

	/*
	 * The event TIME_CONV was extended for the fields from "time_cycles"
	 * when supported cap_user_time_short, for backward compatibility,
	 * prints the extended fields only if they are contained in the event.
	 */
	if (event_contains(*tc, time_cycles)) {
		ret += fprintf(fp, "... Time Cycles     %" PRI_lu64 "\n",
			       tc->time_cycles);
		ret += fprintf(fp, "... Time Mask       %#" PRI_lx64 "\n",
			       tc->time_mask);
		ret += fprintf(fp, "... Cap Time Zero   %" PRId32 "\n",
			       tc->cap_user_time_zero);
		ret += fprintf(fp, "... Cap Time Short  %" PRId32 "\n",
			       tc->cap_user_time_short);
	}

	return ret;
}

Annotation

Implementation Notes