linux-cpupower-5.5-rc1

This cpupower update for Linux 5.5-rc1 consists of bug fixes and
 improvements to make it more accurate by removing the userspace
 to kernel transition and read_msr initiated IPI delays.
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Merge tag 'linux-cpupower-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux

Pull cpupower utility updates for v5.5 from Shuah Khan:

"This cpupower update for Linux 5.5-rc1 consists of bug fixes and
 improvements to make it more accurate by removing the userspace
 to kernel transition and read_msr initiated IPI delays."

* tag 'linux-cpupower-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux:
  cpupower: ToDo: Update ToDo with ideas for per_cpu_schedule handling
  cpupower: mperf_monitor: Update cpupower to use the RDPRU instruction
  cpupower: mperf_monitor: Introduce per_cpu_schedule flag
  cpupower: Move needs_root variable into a sub-struct
  cpupower : Handle set and info subcommands correctly
  tools/power/cpupower: Fix initializer override in hsw_ext_cstates

tools/power/cpupower/ToDo

@@ -8,3 +8,17 @@ ToDos sorted by priority:
 - Add another c1e debug idle monitor
   -> Is by design racy with BIOS, but could be added
      with a --force option and some "be careful" messages
+- Add cpu_start()/cpu_stop() callbacks for monitor
+  -> This is to move the per_cpu logic from inside the
+     monitor to outside it. This can be given higher
+     priority in fork_it.
+- Fork as many processes as there are CPUs in case the
+  per_cpu_schedule flag is set.
+  -> Bind forked process to each cpu.
+  -> Execute start measures via the forked processes on
+     each cpu.
+  -> Run test executable in a forked process.
+  -> Execute stop measures via the forked processes on
+     each cpu.
+  This would be ideal as it will not introduce noise in the
+  tested executable.

tools/power/cpupower/utils/cpupower-info.c

@@ -10,6 +10,7 @@
 #include <errno.h>
 #include <string.h>
 #include <getopt.h>
+#include <sys/utsname.h>
 
 #include "helpers/helpers.h"
 #include "helpers/sysfs.h"
@@ -30,6 +31,7 @@ int cmd_info(int argc, char **argv)
 	extern char *optarg;
 	extern int optind, opterr, optopt;
 	unsigned int cpu;
+	struct utsname uts;
 
 	union {
 		struct {
@@ -39,6 +41,13 @@ int cmd_info(int argc, char **argv)
 	} params = {};
 	int ret = 0;
 
+	ret = uname(&uts);
+	if (!ret && (!strcmp(uts.machine, "ppc64le") ||
+		     !strcmp(uts.machine, "ppc64"))) {
+		fprintf(stderr, _("Subcommand not supported on POWER.\n"));
+		return ret;
+	}
+
 	setlocale(LC_ALL, "");
 	textdomain(PACKAGE);
 

tools/power/cpupower/utils/cpupower-set.c

@@ -10,6 +10,7 @@
 #include <errno.h>
 #include <string.h>
 #include <getopt.h>
+#include <sys/utsname.h>
 
 #include "helpers/helpers.h"
 #include "helpers/sysfs.h"
@@ -31,6 +32,7 @@ int cmd_set(int argc, char **argv)
 	extern char *optarg;
 	extern int optind, opterr, optopt;
 	unsigned int cpu;
+	struct utsname uts;
 
 	union {
 		struct {
@@ -41,6 +43,13 @@ int cmd_set(int argc, char **argv)
 	int perf_bias = 0;
 	int ret = 0;
 
+	ret = uname(&uts);
+	if (!ret && (!strcmp(uts.machine, "ppc64le") ||
+		     !strcmp(uts.machine, "ppc64"))) {
+		fprintf(stderr, _("Subcommand not supported on POWER.\n"));
+		return ret;
+	}
+
 	setlocale(LC_ALL, "");
 	textdomain(PACKAGE);
 

tools/power/cpupower/utils/helpers/cpuid.c

@@ -131,6 +131,10 @@ int get_cpu_info(struct cpupower_cpu_info *cpu_info)
 		if (ext_cpuid_level >= 0x80000007 &&
 		    (cpuid_edx(0x80000007) & (1 << 9)))
 			cpu_info->caps |= CPUPOWER_CAP_AMD_CBP;
+
+		if (ext_cpuid_level >= 0x80000008 &&
+		    cpuid_ebx(0x80000008) & (1 << 4))
+			cpu_info->caps |= CPUPOWER_CAP_AMD_RDPRU;
 	}
 
 	if (cpu_info->vendor == X86_VENDOR_INTEL) {

tools/power/cpupower/utils/helpers/helpers.h

@@ -69,6 +69,7 @@ enum cpupower_cpu_vendor {X86_VENDOR_UNKNOWN = 0, X86_VENDOR_INTEL,
 #define CPUPOWER_CAP_HAS_TURBO_RATIO	0x00000010
 #define CPUPOWER_CAP_IS_SNB		0x00000020
 #define CPUPOWER_CAP_INTEL_IDA		0x00000040
+#define CPUPOWER_CAP_AMD_RDPRU		0x00000080
 
 #define CPUPOWER_AMD_CPBDIS		0x02000000
 

tools/power/cpupower/utils/idle_monitor/amd_fam14h_idle.c

@@ -328,7 +328,7 @@ struct cpuidle_monitor amd_fam14h_monitor = {
 	.stop			= amd_fam14h_stop,
 	.do_register		= amd_fam14h_register,
 	.unregister		= amd_fam14h_unregister,
-	.needs_root		= 1,
+	.flags.needs_root	= 1,
 	.overflow_s		= OVERFLOW_MS / 1000,
 };
 #endif /* #if defined(__i386__) || defined(__x86_64__) */

tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c

@@ -207,6 +207,6 @@ struct cpuidle_monitor cpuidle_sysfs_monitor = {
 	.stop			= cpuidle_stop,
 	.do_register		= cpuidle_register,
 	.unregister		= cpuidle_unregister,
-	.needs_root		= 0,
+	.flags.needs_root	= 0,
 	.overflow_s		= UINT_MAX,
 };

tools/power/cpupower/utils/idle_monitor/cpupower-monitor.c

@@ -408,7 +408,7 @@ int cmd_monitor(int argc, char **argv)
 		dprint("Try to register: %s\n", all_monitors[num]->name);
 		test_mon = all_monitors[num]->do_register();
 		if (test_mon) {
-			if (test_mon->needs_root && !run_as_root) {
+			if (test_mon->flags.needs_root && !run_as_root) {
 				fprintf(stderr, _("Available monitor %s needs "
 					  "root access\n"), test_mon->name);
 				continue;

tools/power/cpupower/utils/idle_monitor/cpupower-monitor.h

@@ -60,7 +60,10 @@ struct cpuidle_monitor {
 	struct cpuidle_monitor* (*do_register) (void);
 	void (*unregister)(void);
 	unsigned int overflow_s;
-	int needs_root;
+	struct {
+		unsigned int needs_root:1;
+		unsigned int per_cpu_schedule:1;
+	} flags;
 };
 
 extern long long timespec_diff_us(struct timespec start, struct timespec end);

tools/power/cpupower/utils/idle_monitor/hsw_ext_idle.c

@@ -39,7 +39,6 @@ static cstate_t hsw_ext_cstates[HSW_EXT_CSTATE_COUNT] = {
 	{
 		.name			= "PC9",
 		.desc			= N_("Processor Package C9"),
-		.desc			= N_("Processor Package C2"),
 		.id			= PC9,
 		.range			= RANGE_PACKAGE,
 		.get_count_percent	= hsw_ext_get_count_percent,
@@ -188,7 +187,7 @@ struct cpuidle_monitor intel_hsw_ext_monitor = {
 	.stop			= hsw_ext_stop,
 	.do_register		= hsw_ext_register,
 	.unregister		= hsw_ext_unregister,
-	.needs_root		= 1,
+	.flags.needs_root	= 1,
 	.overflow_s		= 922000000 /* 922337203 seconds TSC overflow
 					       at 20GHz */
 };

tools/power/cpupower/utils/idle_monitor/mperf_monitor.c

@@ -19,6 +19,10 @@
 #define MSR_APERF	0xE8
 #define MSR_MPERF	0xE7
 
+#define RDPRU ".byte 0x0f, 0x01, 0xfd"
+#define RDPRU_ECX_MPERF	0
+#define RDPRU_ECX_APERF	1
+
 #define MSR_TSC	0x10
 
 #define MSR_AMD_HWCR 0xc0010015
@@ -86,15 +90,51 @@ static int mperf_get_tsc(unsigned long long *tsc)
 	return ret;
 }
 
-static int mperf_init_stats(unsigned int cpu)
+static int get_aperf_mperf(int cpu, unsigned long long *aval,
+				    unsigned long long *mval)
 {
-	unsigned long long val;
+	unsigned long low_a, high_a;
+	unsigned long low_m, high_m;
 	int ret;
 
-	ret = read_msr(cpu, MSR_APERF, &val);
-	aperf_previous_count[cpu] = val;
-	ret |= read_msr(cpu, MSR_MPERF, &val);
-	mperf_previous_count[cpu] = val;
+	/*
+	 * Running on the cpu from which we read the registers will
+	 * prevent APERF/MPERF from going out of sync because of IPI
+	 * latency introduced by read_msr()s.
+	 */
+	if (mperf_monitor.flags.per_cpu_schedule) {
+		if (bind_cpu(cpu))
+			return 1;
+	}
+
+	if (cpupower_cpu_info.caps & CPUPOWER_CAP_AMD_RDPRU) {
+		asm volatile(RDPRU
+			     : "=a" (low_a), "=d" (high_a)
+			     : "c" (RDPRU_ECX_APERF));
+		asm volatile(RDPRU
+			     : "=a" (low_m), "=d" (high_m)
+			     : "c" (RDPRU_ECX_MPERF));
+
+		*aval = ((low_a) | (high_a) << 32);
+		*mval = ((low_m) | (high_m) << 32);
+
+		return 0;
+	}
+
+	ret  = read_msr(cpu, MSR_APERF, aval);
+	ret |= read_msr(cpu, MSR_MPERF, mval);
+
+	return ret;
+}
+
+static int mperf_init_stats(unsigned int cpu)
+{
+	unsigned long long aval, mval;
+	int ret;
+
+	ret = get_aperf_mperf(cpu, &aval, &mval);
+	aperf_previous_count[cpu] = aval;
+	mperf_previous_count[cpu] = mval;
 	is_valid[cpu] = !ret;
 
 	return 0;
@@ -102,13 +142,12 @@ static int mperf_init_stats(unsigned int cpu)
 
 static int mperf_measure_stats(unsigned int cpu)
 {
-	unsigned long long val;
+	unsigned long long aval, mval;
 	int ret;
 
-	ret = read_msr(cpu, MSR_APERF, &val);
-	aperf_current_count[cpu] = val;
-	ret |= read_msr(cpu, MSR_MPERF, &val);
-	mperf_current_count[cpu] = val;
+	ret = get_aperf_mperf(cpu, &aval, &mval);
+	aperf_current_count[cpu] = aval;
+	mperf_current_count[cpu] = mval;
 	is_valid[cpu] = !ret;
 
 	return 0;
@@ -305,6 +344,9 @@ struct cpuidle_monitor *mperf_register(void)
 	if (init_maxfreq_mode())
 		return NULL;
 
+	if (cpupower_cpu_info.vendor == X86_VENDOR_AMD)
+		mperf_monitor.flags.per_cpu_schedule = 1;
+
 	/* Free this at program termination */
 	is_valid = calloc(cpu_count, sizeof(int));
 	mperf_previous_count = calloc(cpu_count, sizeof(unsigned long long));
@@ -333,7 +375,7 @@ struct cpuidle_monitor mperf_monitor = {
 	.stop			= mperf_stop,
 	.do_register		= mperf_register,
 	.unregister		= mperf_unregister,
-	.needs_root		= 1,
+	.flags.needs_root	= 1,
 	.overflow_s		= 922000000 /* 922337203 seconds TSC overflow
 					       at 20GHz */
 };

tools/power/cpupower/utils/idle_monitor/nhm_idle.c

@@ -208,7 +208,7 @@ struct cpuidle_monitor intel_nhm_monitor = {
 	.stop			= nhm_stop,
 	.do_register		= intel_nhm_register,
 	.unregister		= intel_nhm_unregister,
-	.needs_root		= 1,
+	.flags.needs_root	= 1,
 	.overflow_s		= 922000000 /* 922337203 seconds TSC overflow
 					       at 20GHz */
 };

tools/power/cpupower/utils/idle_monitor/snb_idle.c

@@ -192,7 +192,7 @@ struct cpuidle_monitor intel_snb_monitor = {
 	.stop			= snb_stop,
 	.do_register		= snb_register,
 	.unregister		= snb_unregister,
-	.needs_root		= 1,
+	.flags.needs_root	= 1,
 	.overflow_s		= 922000000 /* 922337203 seconds TSC overflow
 					       at 20GHz */
 };