On Sun, 06 May 2012 23:51:26 -0700
Eric Anholt <eric at anholt.net> wrote:
> On Fri, 4 May 2012 18:58:59 -0700, Ben Widawsky <ben at bwidawsk.net> wrote:
> > I'm seeing about a 5% FPS improvement across various benchmarks on my
> > IVB i3. Rumor has it that the higher end parts show even more benefit.
> >
> > This derives from a patch originally given to me by Bernard. The docs
> > are confusing about the definition names (ie. medium really seems like
> > max), but it would seem it gives more cache to the GT at the expense of
> > uncore. This configuration makes the split most in favor of the GT. I've
> > not tried the other IDICOS values.
>
> My IVB system started with an SNBPCR value of 0x1b40. To test the effect of
> this patch, I just smashed the value of the reg at runtime:
>
> Results:
> x intel_reg_write 0x900c 0x001b40
> + intel_reg_write 0x900c 0x201b40
>
> citybench:
> +------------------------------------------------------------------------------+
> | xxx + |
> | x xxx + + + |
> | x xxx + +++ |
> | x xxx + + ++++ |
> | xx xxxx + + ++++ |
> |x xxx x xxxx + + ++++++ ++ |
> |xxxxx xxxxxxxx + + + + +*++++ ++ |
> |xxxxxxxxx xxxxxxxx x +++++ ++++ +*+++++++ |
> |xxxxxxxxx xxxxxxxxxx x ++++++++++ ++**+++++++ + + |
> |xxxxxxxxx xxxxxxxxxxxxxx *++++++++++++ ****+*++++++++ + ++++++ +|
> | |___________AM_________| |_________A_M_______| |
> +------------------------------------------------------------------------------+
> N Min Max Median Avg Stddev
> x 118 335.779 387.456 354.306 352.63131 12.462796
> + 118 367.324 419.02 386.14 384.47139 10.970918
> Difference at 95.0% confidence
> 31.8401 +/- 2.99585
> 9.02928% +/- 0.849569%
> (Student's t, pooled s = 11.7406)
>
> openarena:
> +------------------------------------------------------------------------------+
> | + ++ xx xx x x xx |
> | + + ++ + + xxxxxxx xxxxx |
> | +++ ++++++++++ ++++++ ++ + x xxxxxxxxxxxxxxx xx|
> |++ + ++++++++++++++++++++++++++++ + + + x x xxxxxxxxxxxxxxxxxx xx|
> | |_________A________| |_____A____| |
> +------------------------------------------------------------------------------+
> N Min Max Median Avg Stddev
> x 65 273.5 292.2 284 283.73385 4.2561822
> + 65 234.8 263.2 249.9 249.6 6.9873323
> Difference at 95.0% confidence
> -34.1338 +/- 1.989
> -12.0302% +/- 0.70101%
>
> nexuiz:
> +------------------------------------------------------------------------------+
> | + |
> | x + + |
> | + x x xx *x+ +x |
> |+ + + x *x+x xxx + x++ + x+*xxxx+x***x+++*x**+x ++ *+|
> | |____|____________AAM____M_____|______| |
> +------------------------------------------------------------------------------+
> N Min Max Median Avg Stddev
> x 33 74.314888 76.177197 75.424764 75.332161 0.48205891
> + 33 73.397254 76.219868 75.584749 75.363209 0.69408523
>
> Using these 3 tests, this patch does not look like a win. Note that OA
> is the most CPU-bound of these, while nexuiz is usually on the edge
> between being CPU and GPU-bound, and citybench is definitely GPU
> limited.
Strange. It would be helpful to start to investigate these systems I
suppose. This is basically what I see on my SNB (though I use xonotic
instead of nexuiz). My SNB is an i7, and my IVB is an i3.
Below are the interesting ones from IVB (I've lost OA somehow).
x xonotic_dinq_fps
+ xonotic_poland_fps
+----------------------------------------------------------------------+
| x xx + |
|x x xx +*x *x+ + + ++ + +|
| |_____A_M___| |_______________________A_____________M__________||
+----------------------------------------------------------------------+
N Min Max Median Avg Stddev
x 11 98.398296 101.24008 100.58156 100.19283 0.97987835
+ 11 100.33134 109.63333 107.76804 105.6379 3.939517
Difference at 95.0% confidence
5.44507 +/- 2.55327
5.43459% +/- 2.54835%
(Student's t, pooled s = 2.87054)
Not sure why my citybench numbers are so low
x citybench_dinq_fps
+ citybench_poland_fps
+----------------------------------------------------------------------+
| xxxxxx x + + + |
|+x xxxxxxx xx x + + + + + ++ + + ++ ++ +|
| |_MA__| |_________________AM________________| |
+----------------------------------------------------------------------+
N Min Max Median Avg Stddev
x 26 196.857 200.568 198.4245 198.56062 0.8468172
+ 18 196.69 215.299 208.6485 208.31394 4.8783414
Difference at 95.0% confidence
9.75333 +/- 1.96251
4.91202% +/- 0.988368%
(Student's t, pooled s = 3.17166)
--
Ben Widawsky, Intel Open Source Technology Center
