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authorThomas Renninger <trenn@suse.de>2012-11-27 16:17:48 +0400
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2012-11-28 02:07:20 +0400
commitc8cfc3c6bf404b0f110631d5bba234982e6ad24f (patch)
treedd6e71768799b81cca6e78fb0a26a45526a5af85 /tools/power/cpupower/man
parentea1021ffa65a81da3d393fcbd7509d6e40d4d325 (diff)
downloadlinux-c8cfc3c6bf404b0f110631d5bba234982e6ad24f.tar.xz
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>
Diffstat (limited to 'tools/power/cpupower/man')
-rw-r--r--tools/power/cpupower/man/cpupower-monitor.115
1 files changed, 13 insertions, 2 deletions
diff --git a/tools/power/cpupower/man/cpupower-monitor.1 b/tools/power/cpupower/man/cpupower-monitor.1
index 1141c2073719..e01c35d13b6e 100644
--- a/tools/power/cpupower/man/cpupower-monitor.1
+++ b/tools/power/cpupower/man/cpupower-monitor.1
@@ -7,11 +7,11 @@ cpupower\-monitor \- Report processor frequency and idle statistics
.RB "\-l"
.B cpupower monitor
-.RB [ "\-m <mon1>," [ "<mon2>,..." ] ]
+.RB [ -c ] [ "\-m <mon1>," [ "<mon2>,..." ] ]
.RB [ "\-i seconds" ]
.br
.B cpupower monitor
-.RB [ "\-m <mon1>," [ "<mon2>,..." ] ]
+.RB [ -c ][ "\-m <mon1>," [ "<mon2>,..." ] ]
.RB command
.br
.SH DESCRIPTION
@@ -64,6 +64,17 @@ Only display specific monitors. Use the monitor string(s) provided by \-l option
Measure intervall.
.RE
.PP
+\-c
+.RS 4
+Schedule the process on every core before starting and ending measuring.
+This could be needed for the Idle_Stats monitor when no other MSR based
+monitor (has to be run on the core that is measured) is run in parallel.
+This is to wake up the processors from deeper sleep states and let the
+kernel re
+-account its cpuidle (C-state) information before reading the
+cpuidle timings from sysfs.
+.RE
+.PP
command
.RS 4
Measure idle and frequency characteristics of an arbitrary command/workload.