On 2016.09.04 16:55 Rafael J. Wysocki wrote:
> On Sunday, September 04, 2016 08:54:49 AM Doug Smythies wrote:
>> On 2016.09.02 17:57 Rafael J. Wysocki wrote:
>>
>>> This is a new version of the "iowait boost" series I posted a few weeks
>>> ago. Since the first two patches from that series have been reworked and
>>> are in linux-next now, I've rebased this series on top of my linux-next
>>> branch.
>>>
>>> In addition to that I took the Doug's feedback into account in the
>>> intel_pstate patches [2-3/4].
>>
>> You got ahead of me a little.
>> Recall the suggestion for the addition of some filtering was based
>> on energy savings. And further that it might make sense to use
>> average pstate as input to the filter (your new patch 3 of 4).
>> In my testing (of the old patch set) I have been finding that some
>> of those energy savings are being given back by the average pstate
>> method, putting its value added into question.
>>
>> Switching to the new patch set, I made two kernels (based on 4.8-rc4
>> + your pre-requisite 2 patches):
>> rfc4: has all 4 patches.
>> rfc2: has patches 1, 2, 4. (does not have the average pstate change)
>>
>> Using my SpecPower simulator test at 20% load I get:
>>
>> Unpatched (reference): ~5905 Joules
19.68 watts
>> rfc4: ~ 6232 Joules (+5.5%)
20.77 watts
>> rfc2: ~ 6075 Joules (+2.9%)
20.25 watts
>> Old rfc, no filter (restated): ~7197 Joules (+21.9%)
>> Old rfc + old iir filter V2: ~5967 Joules (+1%)
>> Old rfc + old ave pstate method: ~6275 Joules (+6.3%)
The above numbers are all an average of 4 runs of 300 seconds each.
See further down for why I added normalized watts.
>>
>> Srinivas was getting considerably different, but still
>> encouraging, numbers on the real SpecPower test beds.
>>
>> I would like to suggest/ask that those real SpecPower tests be done
>> first so as to decide a preferred way forward. I'll also re-do my
>> simulator tests over a longer time period and at some other loads
>> (currently 20% is hard coded).
>
> The reason I made patch [3/4] separate was to make it easier to test without
> that change. That is, apply [1-2/4] and see what difference it makes.
>
> I'd like to see the results from that if poss.
O.K., that is what I was doing anyway.
I have some more data from my SpecPower simulator test:
Note: My calibration was out by quite a bit, so what I called 20%
was actually about 36.4%. While I knew it was out, I didn't know it
was that much, but I didn't care as it wasn't really relevant to
the compare type tests I was doing. I'll just use "X" in the table
below, where X ~= 18.2% on a real SpecPower.
Big numbers are Joules (package Joules from turbostat)
Smaller numbers are watts, 1500 Seconds test run time.
Load: idle 0.5X X 2X 3X 4X 5X 100%
Unpatched: 5757 11050 16048 29012 47575 61313 76634 81737
3.84 7.37 10.70 19.34 31.72 40.88 51.09 54.49
rfc4: 5723 11323 17079 31561 47666 62625 76286 81664
3.82 7.55 11.39 21.04 31.78 41.75 50.86 54.44
-0.6% 2.5% 6.4% 8.8% 0.2% 2.1% -0.5% -0.1%
rfc2: 5769 11319 17140 30533 45158 61387 75690 81722
3.85 7.55 11.43 20.36 30.11 40.92 50.46 54.48
0.2% 2.4% 6.8% 5.2% -5.1% 0.1% -1.2% 0.0%
And again, 2nd run:
idle 0.5X X 2X 3X 4X 5X 100%
Unpatched: 5708 11037 16075 29147 45913 61165 76650 81695
3.81 7.36 10.72 19.43 30.61 40.78 51.10 54.46
rfc4: 5770 11303 17023 31508 47653 62520 75798 81725
3.85 7.54 11.35 21.01 31.77 41.68 50.53 54.48
1.1% 2.4% 5.9% 8.1% 3.8% 2.2% -1.1% 0.0%
rfc2: 5793 11242 17044 30258 45178 61526 75631 81669
3.86 7.49 11.36 20.17 30.12 41.02 50.42 54.45
1.5% 1.9% 6.0% 3.8% -1.6% 0.6% -1.3% 0.0%
Note: Comparing the 2X data to the further above numbers
from the other day shows more run to run variability than
I had expected. (I have very very few services running
on my test server, so background idle is really quite
idle.)
... Doug
