summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--Documentation/trace/power.txt17
1 files changed, 17 insertions, 0 deletions
diff --git a/Documentation/trace/power.txt b/Documentation/trace/power.txt
new file mode 100644
index 0000000..cd805e1
--- /dev/null
+++ b/Documentation/trace/power.txt
@@ -0,0 +1,17 @@
+The power tracer collects detailed information about C-state and P-state
+transitions, instead of just looking at the high-level "average"
+information.
+
+There is a helper script found in scrips/tracing/power.pl in the kernel
+sources which can be used to parse this information and create a
+Scalable Vector Graphics (SVG) picture from the trace data.
+
+To use this tracer:
+
+ echo 0 > /sys/kernel/debug/tracing/tracing_enabled
+ echo power > /sys/kernel/debug/tracing/current_tracer
+ echo 1 > /sys/kernel/debug/tracing/tracing_enabled
+ sleep 1
+ echo 0 > /sys/kernel/debug/tracing/tracing_enabled
+ cat /sys/kernel/debug/tracing/trace | \
+ perl scripts/tracing/power.pl > out.sv