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.
Re-testing, openarena (1024x768) currently is about a 2.5% +/- 0.5%
loss (lost the numbers). Also, new tropics numbers:
N Min Max Median Avg Stddev
x 70 21.9718 22.2166 22.1556 22.154501 0.029139432
+ 69 22.7246 22.9308 22.8914 22.888735 0.027248939
Difference at 95.0% confidence
0.734233 +/- 0.00938209
3.31415% +/- 0.0423485%
(Student's t, pooled s = 0.0282169)
That swings things in favor of the patch for me.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 197 bytes
Desc: not available
URL: <http://lists.freedesktop.org/archives/intel-gfx/attachments/20120613/712abd94/attachment.pgp>
