perf timechart: Add a power-only mode

For doing work on the Linux power management components, I need to
make long (30+ seconds) traces. Currently, this then results in a
HUGE svg file, with mostly process data that isn't interesting.

This patch adds a --power-only mode to perf timechart that only
outputs the CPU power section of the SVG; this significantly
reduces the size of the SVG file, making even 30+ second traces
viewable with inkscape.

As a minor tweak for the same effect, the minimum text size is
decreased; current inkscape cannot zoom in deep enough to show text
this small, but it reduces inkscape compute time.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: peterz@infradead.org
LKML-Reference: <20090924154013.0675ab71@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/Documentation/perf-timechart.txt

@@ -31,6 +31,9 @@ OPTIONS
 -w::
 --width=::
         Select the width of the SVG file (default: 1000)
+-p::
+--power-only::
+        Only output the CPU power section of the diagram
 
 
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