Commit d76bb7a0 authored by Len Brown's avatar Len Brown
Browse files

tools/power turbostat: Print /dev/cpu_dma_latency 



Users are puzzled when they use tuned performance and all their
C-states vanish.  Dump /dev/cpu_dma_latency and state
whether the value is default, or constraining,
to explain this situation.

Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent e00b62f0

tools/power/x86/turbostat/turbostat.c

+28 −0
Original line number Diff line number Diff line
@@ -4698,6 +4698,32 @@ unsigned int intel_model_duplicates(unsigned int model) 
	}

	return model;

}



void print_dev_latency(void)

{

	char *path = "/dev/cpu_dma_latency";

	int fd;

	int value;

	int retval;



	fd = open(path, O_RDONLY);

	if (fd < 0) {

		warn("fopen %s\n", path);

		return;

	}



	retval = read(fd, (void *)&value, sizeof(int));

	if (retval != sizeof(int)) {

		warn("read %s\n", path);

		close(fd);

		return;

	}

	fprintf(outf, "/dev/cpu_dma_latency: %d usec (%s)\n",

		value, value == 2000000000 ? "default" : "constrained");



	close(fd);

}



void process_cpuid()

{

	unsigned int eax, ebx, ecx, edx;
@@ -4966,6 +4992,8 @@ void process_cpuid() 
	if (!quiet)

		dump_cstate_pstate_config_info(family, model);



	if (!quiet)

		print_dev_latency();

	if (!quiet)

		dump_sysfs_cstate_config();

	if (!quiet)