cpupowerutils - cpufrequtils extended with quite some features

CPU power consumption vs performance tuning is no longer
limited to CPU frequency switching anymore: deep sleep states,
traditional dynamic frequency scaling and hidden turbo/boost
frequencies are tied close together and depend on each other.
The first two exist on different architectures like PPC, Itanium and
ARM, the latter (so far) only on X86. On X86 the APU (CPU+GPU) will
only run most efficiently if CPU and GPU has proper power management
in place.

Users and Developers want to have *one* tool to get an overview what
their system supports and to monitor and debug CPU power management
in detail. The tool should compile and work on as many architectures
as possible.

Once this tool stabilizes a bit, it is intended to replace the
Intel-specific tools in tools/power/x86

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

1 files changed, 122 insertions, 0 deletions

diff --git a/tools/power/cpupower/utils/helpers/msr.c b/tools/power/cpupower/utils/helpers/msr.c
new file mode 100644
index 000000000000..93d48bd56e57
--- /dev/null
+++ b/tools/power/cpupower/utils/helpers/msr.c
@@ -0,0 +1,122 @@
+#if defined(__i386__) || defined(__x86_64__)
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdint.h>
+
+#include "helpers/helpers.h"
+
+/* Intel specific MSRs */
+#define MSR_IA32_PERF_STATUS		0x198
+#define MSR_IA32_MISC_ENABLES		0x1a0
+#define MSR_IA32_ENERGY_PERF_BIAS	0x1b0
+
+/*
+ * read_msr
+ *
+ * Will return 0 on success and -1 on failure.
+ * Possible errno values could be:
+ * EFAULT -If the read/write did not fully complete
+ * EIO    -If the CPU does not support MSRs
+ * ENXIO  -If the CPU does not exist
+ */
+
+int read_msr(int cpu, unsigned int idx, unsigned long long *val)
+{
+	int fd;
+	char msr_file_name[64];
+
+	sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu);
+	fd = open(msr_file_name, O_RDONLY);
+	if (fd < 0)
+		return -1;
+	if (lseek(fd, idx, SEEK_CUR) == -1)
+		goto err;
+	if (read(fd, val, sizeof *val) != sizeof *val)
+		goto err;
+	close(fd);
+	return 0;
+ err:
+	close(fd);
+	return -1;
+}
+
+/*
+ * write_msr
+ *
+ * Will return 0 on success and -1 on failure.
+ * Possible errno values could be:
+ * EFAULT -If the read/write did not fully complete
+ * EIO    -If the CPU does not support MSRs
+ * ENXIO  -If the CPU does not exist
+ */
+int write_msr(int cpu, unsigned int idx, unsigned long long val)
+{
+	int fd;
+	char msr_file_name[64];
+
+	sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu);
+	fd = open(msr_file_name, O_WRONLY);
+	if (fd < 0)
+		return -1;
+	if (lseek(fd, idx, SEEK_CUR) == -1)
+		goto err;
+	if (write(fd, &val, sizeof val) != sizeof val)
+		goto err;
+	close(fd);
+	return 0;
+ err:
+	close(fd);
+	return -1;
+}
+
+int msr_intel_has_boost_support(unsigned int cpu)
+{
+	unsigned long long misc_enables;
+	int ret;
+
+	ret = read_msr(cpu, MSR_IA32_MISC_ENABLES, &misc_enables);
+	if (ret)
+		return ret;
+	return (misc_enables >> 38) & 0x1;
+}
+
+int msr_intel_boost_is_active(unsigned int cpu)
+{
+	unsigned long long perf_status;
+	int ret;
+
+	ret = read_msr(cpu, MSR_IA32_PERF_STATUS, &perf_status);
+	if (ret)
+		return ret;
+	return (perf_status >> 32) & 0x1;
+}
+
+int msr_intel_get_perf_bias(unsigned int cpu)
+{
+	unsigned long long val;
+	int ret;
+
+	if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_PERF_BIAS))
+		return -1;
+
+	ret = read_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS, &val);
+	if (ret)
+		return ret;
+	return val;
+}
+
+int msr_intel_set_perf_bias(unsigned int cpu, unsigned int val)
+{
+	int ret;
+
+	if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_PERF_BIAS))
+		return -1;
+
+	ret = write_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS, val);
+	if (ret)
+		return ret;
+	return 0;
+}
+#endif