cpupower: Provide -c param for cpupower monitor to schedule process on all cores

If an MSR based monitor is run in parallel this is not needed. This is the
default case on all/most Intel machines.

But when only sysfs info is read via cpupower monitor -m Idle_Stats (typically
the case for non root users) or when other monitors are PCI based (AMD),
Idle_Stats, read from sysfs can be totally bogus:

cpupower monitor -m Idle_Stats
PKG |CORE|CPU | POLL | C1-N | C3-N | C6-N
   0|   0|   0|  0.00|  0.00|  0.24| 99.81
   0|   0|  32|  0.00|  0.00|  0.00| 100.7
...
   0|  17|  20|  0.00|  0.00|  0.00| 173.1
   0|  17|  52|  0.00|  0.00|  0.07| 173.0
   0|  18|  68|  0.00|  0.00|  0.00|  0.00
   0|  18|  76|  0.00|  0.00|  0.00|  0.00
...

With the -c option all cores are woken up and the kernel
did update cpuidle statistics before reading out sysfs.
This causes some overhead. Therefore avoid if possible, use
if needed:

cpupower monitor -c -m Idle_Stats
PKG |CORE|CPU | POLL | C1-N | C3-N | C6-N
   0|   0|   0|  0.00|  0.00|  0.00| 100.2
   0|   0|  32|  0.00|  0.00|  0.00| 100.2
...
   0|   8|   8|  0.00|  0.00|  0.00| 99.82
   0|   8|  40|  0.00|  0.00|  0.00| 99.81
   0|   9|  24|  0.00|  0.00|  0.00| 100.3
   0|   9|  56|  0.00|  0.00|  0.00| 100.2
   0|  16|   4|  0.00|  0.00|  0.00| 99.75
   0|  16|  36|  0.00|  0.00|  0.00| 99.38
...

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 17 insertions, 1 deletions

diff --git a/tools/power/cpupower/utils/idle_monitor/cpupower-monitor.c b/tools/power/cpupower/utils/idle_monitor/cpupower-monitor.c
index 7a657f3da23b..c4bae9203a69 100644
--- a/tools/power/cpupower/utils/idle_monitor/cpupower-monitor.c
+++ b/tools/power/cpupower/utils/idle_monitor/cpupower-monitor.c
@@ -39,6 +39,7 @@ static int mode;
 static int interval = 1;
 static char *show_monitors_param;
 static struct cpupower_topology cpu_top;
+static unsigned int wake_cpus;
 
 /* ToDo: Document this in the manpage */
 static char range_abbr[RANGE_MAX] = { 'T', 'C', 'P', 'M', };
@@ -314,16 +315,28 @@ int fork_it(char **argv)
 int do_interval_measure(int i)
 {
 	unsigned int num;
+	int cpu;
+
+	if (wake_cpus)
+		for (cpu = 0; cpu < cpu_count; cpu++)
+			bind_cpu(cpu);
 
 	for (num = 0; num < avail_monitors; num++) {
 		dprint("HW C-state residency monitor: %s - States: %d\n",
 		       monitors[num]->name, monitors[num]->hw_states_num);
 		monitors[num]->start();
 	}
+
 	sleep(i);
+
+	if (wake_cpus)
+		for (cpu = 0; cpu < cpu_count; cpu++)
+			bind_cpu(cpu);
+
 	for (num = 0; num < avail_monitors; num++)
 		monitors[num]->stop();
 
+
 	return 0;
 }
 
@@ -332,7 +345,7 @@ static void cmdline(int argc, char *argv[])
 	int opt;
 	progname = basename(argv[0]);
 
-	while ((opt = getopt(argc, argv, "+li:m:")) != -1) {
+	while ((opt = getopt(argc, argv, "+lci:m:")) != -1) {
 		switch (opt) {
 		case 'l':
 			if (mode)
@@ -351,6 +364,9 @@ static void cmdline(int argc, char *argv[])
 			mode = show;
 			show_monitors_param = optarg;
 			break;
+		case 'c':
+			wake_cpus = 1;
+			break;
 		default:
 			print_wrong_arg_exit();
 		}