On Tue, 21 Jun 2011 15:24:24 -0700, Jesse Barnes <jbar...@virtuousgeek.org> wrote: > The ring frequency scaling table tells the PCU to treat certain GPU > frequencies as if they were a given CPU frequency for purposes of > scaling the ring frequency. Normally the PCU will scale the ring > frequency based on the CPU P-state, but with the table present, it will > also take the GPU frequency into account. The scaling_factor used in > this patch may not be ideal, but is enough to increase performance in > nexuiz on a 1366x768 panel by about 20%. > > The main downside of keeping the ring frequency high while the CPU is > at a low frequency (or asleep altogether) is increased power > consumption. But then if you're keeping your GPU busy, you probably > want the extra performance.
The intent of the patch sounds good, but it doesn't seem to be doing
anything here (graphs below). If I run a "while true; do; done" loop to
keep a CPU busy during measurement, though, OA gets a 15.9% +/- 0.6%
win, and nexuiz around 20%. There are no complaints in dmesg.
x /home/anholt/nexuiz-before
+ /home/anholt/nexuiz-after
+-------------------------------------------------------------------------------+
| x + + x x
+|
||_|_______________________M____MA_____A_________________________|_________|
|
+-------------------------------------------------------------------------------+
N Min Max Median Avg Stddev
x 3 59.217461 59.775295 59.479322 59.490693 0.27909057
+ 3 59.287311 59.893383 59.440451 59.540382 0.31515189
No difference proven at 95.0% confidence
x /home/anholt/oa-before
+ /home/anholt/oa-after
+-------------------------------------------------------------------------------+
|x x + + + x * +
x|
| |________________________|_________MA_______A______M__________|________|
|
+-------------------------------------------------------------------------------+
N Min Max Median Avg Stddev
x 5 184.2 187.2 186.3 185.72 1.3809417
+ 5 185.4 187 185.7 186.04 0.71624018
No difference proven at 95.0% confidence
x /home/anholt/taiji-before
+ /home/anholt/taiji-after
+-------------------------------------------------------------------------------+
|x x + xx + x + ++ +
x|
| |____________________________A___|______________A______M_|_____|
|
+-------------------------------------------------------------------------------+
N Min Max Median Avg Stddev
x 6 132.486 139.931 135.608 135.596 2.6966051
+ 6 134.974 138.832 138.111 137.41183 1.434609
No difference proven at 95.0% confidence
pgpBWhmKiVbiy.pgp
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