cgminer and WU (Work Utility)

[kenshirothefist]

Hi,

I'm seeking for experts on cgminer WU.

So, the cgminer WU is the Work Utility defined as the number of diff1 shares work / minute (accepted or rejected).

Please, correct me if I'm wrong. To get the most of my miner, I should optimize my miner to get the highest possible WU (because this is what is actually committed to the pool and thus makes money). In some cases you can get more WU with actually lower hash rates on GPUs. There are different approaches to accomplish this (decreasing intensity, increase/decrease thread concurrency).

Now, to my example: I have miner with 4x XFX R9 290 (all the same, all with the same settings 1015/1500/20481), resulting like this (running for 15 hours):

(5s):3.493M (avg):3.487Mh/s | A:2235392  R:48128  HW:0  WU:3097.8/m

GPU 0:  77.0C 5150RPM | 872.0K/872.6Kh/s | R:  3.0% HW:0 WU:747.8/m T:1 I:19
GPU 1:  80.0C 5250RPM | 873.2K/871.9Kh/s | R:  2.3% HW:0 WU:805.2/m T:1 I:19
GPU 2:  75.0C 5153RPM | 873.2K/871.8Kh/s | R:  3.0% HW:0 WU:736.3/m T:1 I:19
GPU 3:  77.0C 5171RPM | 872.9K/871.9Kh/s | R:  0.3% HW:0 WU:805.4/m T:1 I:19

So, the average WU / hashrate for the whole miner is 3097.8 / 3.487 = 88,8%

However, each card has a very different WU / hashrate:

GPU 0:  85,8%
GPU 1:  92,2%
GPU 2:  84,3%
GPU 3:  92,3%

I know that the WU is dependent on luck finding valid shares on each GPU, but this should stabilize in time. Now, why are there such differences between the cards? Are you experiencing the same thing? Is there any general rule to get the same WU on all cards? Any hints on optimizations to get the highest possible WU?

Thank you!

[BoogieWater]

Just came across your post because the exact same question popped into my head! It seems to me that identical cards with identical settings should have the same WU.  I'm wondering what can be causing this discrepancy.  I have 2 xfx 270's and one or the other will typically end up with a lower than ideal WU after some time, but still have nearly identical hashrates.

Some tips may headed toward anyone who can solve or explain this issue...

Thanks!

[phzi]

Just came across your post because the exact same question popped into my head! It seems to me that identical cards with identical settings should have the same WU.  I'm wondering what can be causing this discrepancy.  I have 2 xfx 270's and one or the other will typically end up with a lower than ideal WU after some time, but still have nearly identical hashrates.

Some tips may headed toward anyone who can solve or explain this issue...

Thanks!

Work units will always vary because of luck.

[BrewCrewFan]

Just came across your post because the exact same question popped into my head! It seems to me that identical cards with identical settings should have the same WU.  I'm wondering what can be causing this discrepancy.  I have 2 xfx 270's and one or the other will typically end up with a lower than ideal WU after some time, but still have nearly identical hashrates.

Some tips may headed toward anyone who can solve or explain this issue...

Thanks!

Work units will always vary because of luck.

Not entierly true. My WU goes up and down depending on my settings.
For instance if I boost up my -I to high my WU goes way down... speed for khash stays the same and most times goes up.

I am not saying luck does not play a ROLE in it, but your settings do affect it also.

[barabashko]

so what is better keeping khashes higher or keeping WU higher?

on 1070 my cards give 745kh (5 cards) but 2800-2900 total WU

and if i downclock to 1040 it gives 720kh but 3450-3500wu

(10 min run first and second)

what is better?

[BrewCrewFan]

so what is better keeping khashes higher or keeping WU higher?

on 1070 my cards give 745kh (5 cards) but 2800-2900 total WU

and if i downclock to 1040 it gives 720kh but 3450-3500wu

(10 min run first and second)

what is better?

The WU because that is the final thing the pools see. That is the shares your submitting. Higher amount of shares = more of a chunk of the block you will get.

For a test to see if I say is true, get on one of those pools that has the worker info refreshed regularly. You will see that the numbers usually reported are equal to your WU rate and not your hash rate.

Also, over time your WU will go down to become a steady output without much change up and down. Usually I let it run a few hours to see where it settles and then tweek when needed.

I know a few people who have ubber tweeks on the 270x's, one person I saw had each card over 500 on his WU... that is sick when you think that the hash rate usually maxes @ 475 high end on those cards lol.

[niceman]

Where are any "science" information about WU depends from settings?
As I understand, after "deep dive" to the mining software and protocols, WU much depends from luck and coin you mine (time between blocks).
It depends from coin because every time you get new coin - you should brake your current work and start new one.

But I don't sure, what WU can depend from settings with same Hashrate, but I'm sure it's totally depends from luck (especially every 10 minutes) and of course from Hashrate.
I think you'll always get higher WU with higher Hashrate if you'll mine Infinite time.

Of course if you have zero HardwareErrors.

[barabashko]

Thanx for your answer BrewCrewFan.
Im on 0 HW for sure.

About pool, for now it says:
5,145 khash

and on the machine it says 3600 WU, how can it be? much luck ? )

[niceman]

Yes. It's much luck . Or wrong pool calculations.
Pool can't see your hashrate. Only result you send.

[Equate]

WU will never be stable they will always fluctuate.

[phzi]

Work units will always vary because of luck.

Not entierly true.
<snip>

Yes... entirely true.  Work units will always vary because of luck.  Certainly some settings will cause your submitted work to vary, that has nothing to do with the existence of luck variance.

[conflict_serum]

WU is luck IF you have Thread concurrency set properly.

If you're getting low WU/WUE, try lowering TC.

I had an issue for a week with mine at 10241 (using xintensity 4)

Dropped to 8193, then finally 5121.

At 5121, I was at ~94%, otherwise below 88%.

[phzi]

WU is luck IF you have Thread concurrency set properly.

If you're getting low WU/WUE, try lowering TC.

I had an issue for a week with mine at 10241 (using xintensity 4)

Dropped to 8193, then finally 5121.

At 5121, I was at ~94%, otherwise below 88%.

It is important to tune TC optimally, but lower is not necessarily better.

(Shader Count * n) + 1
or
(Shader Count * n) - 1

is usually optimal for most cards.  You will have to experiment to find the best n.

[phzi]

\

I am completely new to mining.  Fired up my idle MSI 280X 6G with sgminer today using conf files I found on the forums optimized for the card I have.  I'm seeing 4.252Mh/s, which appears to be good for the card I have, but I am only seeing WU: 0.055/m after running for about 6 hours, which appears to be just about nil compared to what everyone else is reporting.

Can anyone tell me what I'm doing wrong?  Here are the conf settings I'm using:
<snip>

What are you mining?  What algorithm?  sha? scrypt?

[phzi]

Downloaded the latest sgminer 5.0 beta build and started from a clean conf file and the darkcoin-mod kernel.  I'm getting virtually the same results.  This setup is only making pennies per day.  Extremely frustrating!   

WU around 0.055/m for X11 at that hashrate is correct.  I see 0.06 with a slightly higher hashrate on X11.

So, nothing is wrong with your setup.