Commit fe0a5788 authored by Borislav Petkov's avatar Borislav Petkov
Browse files

tools/power/x86_energy_perf_policy: Read energy_perf_bias from sysfs 



... and stop poking at the MSR directly.

Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20201029190259.3476-4-bp@alien8.de
parent 6d6501d9

tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c

+99 −10
Original line number Diff line number Diff line
@@ -91,6 +91,9 @@ unsigned int has_hwp_request_pkg; /* IA32_HWP_REQUEST_PKG */ 


unsigned int bdx_highest_ratio;



#define PATH_TO_CPU "/sys/devices/system/cpu/"

#define SYSFS_PATH_MAX 255



/*

 * maintain compatibility with original implementation, but don't document it:

 */
@@ -668,6 +671,48 @@ int put_msr(int cpu, int offset, unsigned long long new_msr) 
	return 0;

}



static unsigned int read_sysfs(const char *path, char *buf, size_t buflen)

{

	ssize_t numread;

	int fd;



	fd = open(path, O_RDONLY);

	if (fd == -1)

		return 0;



	numread = read(fd, buf, buflen - 1);

	if (numread < 1) {

		close(fd);

		return 0;

	}



	buf[numread] = '\0';

	close(fd);



	return (unsigned int) numread;

}



static unsigned int write_sysfs(const char *path, char *buf, size_t buflen)

{

	ssize_t numwritten;

	int fd;



	fd = open(path, O_WRONLY);

	if (fd == -1)

		return 0;



	numwritten = write(fd, buf, buflen - 1);

	if (numwritten < 1) {

		perror("write failed\n");

		close(fd);

		return -1;

	}



	close(fd);



	return (unsigned int) numwritten;

}



void print_hwp_cap(int cpu, struct msr_hwp_cap *cap, char *str)

{

	if (cpu != -1)
@@ -745,17 +790,61 @@ void write_hwp_request(int cpu, struct msr_hwp_request *hwp_req, unsigned int ms 
	put_msr(cpu, msr_offset, msr);

}



static int get_epb(int cpu)

{

	char path[SYSFS_PATH_MAX];

	char linebuf[3];

	char *endp;

	long val;



	if (!has_epb)

		return -1;



	snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/power/energy_perf_bias", cpu);



	if (!read_sysfs(path, linebuf, 3))

		return -1;



	val = strtol(linebuf, &endp, 0);

	if (endp == linebuf || errno == ERANGE)

		return -1;



	return (int)val;

}



static int set_epb(int cpu, int val)

{

	char path[SYSFS_PATH_MAX];

	char linebuf[3];

	char *endp;

	int ret;



	if (!has_epb)

		return -1;



	snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/power/energy_perf_bias", cpu);

	snprintf(linebuf, sizeof(linebuf), "%d", val);



	ret = write_sysfs(path, linebuf, 3);

	if (ret <= 0)

		return -1;



	val = strtol(linebuf, &endp, 0);

	if (endp == linebuf || errno == ERANGE)

		return -1;



	return (int)val;

}



int print_cpu_msrs(int cpu)

{

	unsigned long long msr;

	struct msr_hwp_request req;

	struct msr_hwp_cap cap;

	int epb;



	if (has_epb) {

		get_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS, &msr);



		printf("cpu%d: EPB %u\n", cpu, (unsigned int) msr);

	}

	epb = get_epb(cpu);

	if (epb >= 0)

		printf("cpu%d: EPB %u\n", cpu, (unsigned int) epb);



	if (!has_hwp)

		return 0;
@@ -1038,15 +1127,15 @@ int enable_hwp_on_cpu(int cpu) 
int update_cpu_msrs(int cpu)

{

	unsigned long long msr;



	int epb;



	if (update_epb) {

		get_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS, &msr);

		put_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS, new_epb);

		epb = get_epb(cpu);

		set_epb(cpu, new_epb);



		if (verbose)

			printf("cpu%d: ENERGY_PERF_BIAS old: %d new: %d\n",

				cpu, (unsigned int) msr, (unsigned int) new_epb);

				cpu, epb, (unsigned int) new_epb);

	}



	if (update_turbo) {