diff options
author | Thomas Renninger <trenn@suse.de> | 2012-11-27 13:17:48 +0100 |
---|---|---|
committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2012-11-27 23:07:20 +0100 |
commit | c8cfc3c6bf404b0f110631d5bba234982e6ad24f (patch) | |
tree | dd6e71768799b81cca6e78fb0a26a45526a5af85 /tools/power/cpupower/man/cpupower-monitor.1 | |
parent | ea1021ffa65a81da3d393fcbd7509d6e40d4d325 (diff) |
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/cpupower-monitor.1')
-rw-r--r-- | tools/power/cpupower/man/cpupower-monitor.1 | 15 |
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. |