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tools/power/x86_energy_perf_policy: Read energy_perf_bias from sysfs

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... and stop poking at the MSR directly.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20201029190259.3476-4-bp@alien8.de
This commit is contained in:
Borislav Petkov 2020-10-15 14:58:48 +02:00
parent 6d6501d912
commit fe0a578862
1 changed files with 99 additions and 10 deletions
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109
tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
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@ -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) {