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Topic: Assessing the impact of TLB trashing on memory hard algorhitms - page 2. (Read 7714 times)

sr. member
Activity: 438
Merit: 250
So we are currently at 1280MB for the DAG file size and most people are still mining. Was the bug fixed?

It turned out the big bug wasn't really there. My (false) assumptions were based on reports by testers of dagSimCL who apparently didn't know how to tune their AMD cards correctly.

The impact of DAG size on hashrate is a fact though. While on Nvidia it has the most dramatic effects in certain circumstances, the impact on AMD cards has been growing steadily now to such a level that the 280X is now dethroned as most cost-effective card to mine on, losing its position to GTX970 on Win7/Linux. 
legendary
Activity: 3808
Merit: 1723
So we are currently at 1280MB for the DAG file size and most people are still mining. Was the bug fixed?
full member
Activity: 189
Merit: 100
I have extracted a solo miner showed resolve, but the server node seems to be ignored, that is, the balls from the miner with chunks.

LOL true. I'm sorry man, just knocked this out blindly without access to an actual AMD card. For now, some further testing by others have indicated there presently no need to worry about allocation problems in the near future. I wil have to verify for myself to be absolutely sure though.

I'd could send you one of my 7950s if you want to pay for shipping i have a bunch laying around due to no motherboards to host them in.

This dag problem is getting huge for my my 900mh/s farm is down to like 700mh/s

The Dag problem is not a problem as it affect all the graphics cards. But I heard that it affects R9 380 less.

I keep hearing this as well, but i don't think I've seen enough data to be sure about this yet, or the reason why the 380s aren't affected. Is it the difference in memory types or what? Also what kind of difference if any does the trashing have on the 380 vs 380X?

Yes. We need more data to assess the situation. I am also interested in knowing the performance of 380 vs 380x.

I have both the 380 and 380x 4G cards and the hash rate is pretty underwhelming 18mh/s vs 19.5 mh/s max it seems.  They are both pretty power hungry too around 240 watts maybe 250 for the x.

a 7950 gets close to 23 mhs/s for around the same power.  One thing i do notice is the hash rate on the 380 and 380x has remained constant regardless of DAG size vs the drop in hash rate of the 7950s to around 22-21 mh/s   not sure to make of all of this .

I think the best bet right now is to get 390s and mix and match them with 380 so at least you get better relsae value on your GPU's vs the older cards unles you can get them really cheap.

the problem with the 390 and 390x is the run crazy hot and consume close to 300 wats of power , thats even worse with a 290x

I'm trying out various brands of 380x cards this week but form my estimation its not worth it to pay anthing more for the 380x at least for mining since it hashes only 5% higer than the 380 and uses more power basically a worthless card.   


380x has 2048 cores while  380 has 1792. The core number is 14% higher, but the hash rate is just 5% high with higher power consumption. So it is not worth it.
legendary
Activity: 2408
Merit: 1102
Leading Crypto Sports Betting & Casino Platform
I have extracted a solo miner showed resolve, but the server node seems to be ignored, that is, the balls from the miner with chunks.

LOL true. I'm sorry man, just knocked this out blindly without access to an actual AMD card. For now, some further testing by others have indicated there presently no need to worry about allocation problems in the near future. I wil have to verify for myself to be absolutely sure though.

I'd could send you one of my 7950s if you want to pay for shipping i have a bunch laying around due to no motherboards to host them in.

This dag problem is getting huge for my my 900mh/s farm is down to like 700mh/s

The Dag problem is not a problem as it affect all the graphics cards. But I heard that it affects R9 380 less.

I keep hearing this as well, but i don't think I've seen enough data to be sure about this yet, or the reason why the 380s aren't affected. Is it the difference in memory types or what? Also what kind of difference if any does the trashing have on the 380 vs 380X?

Yes. We need more data to assess the situation. I am also interested in knowing the performance of 380 vs 380x.

I have both the 380 and 380x 4G cards and the hash rate is pretty underwhelming 18mh/s vs 19.5 mh/s max it seems.  They are both pretty power hungry too around 240 watts maybe 250 for the x.

a 7950 gets close to 23 mhs/s for around the same power.  One thing i do notice is the hash rate on the 380 and 380x has remained constant regardless of DAG size vs the drop in hash rate of the 7950s to around 22-21 mh/s   not sure to make of all of this .

I think the best bet right now is to get 390s and mix and match them with 380 so at least you get better relsae value on your GPU's vs the older cards unles you can get them really cheap.

the problem with the 390 and 390x is the run crazy hot and consume close to 300 wats of power , thats even worse with a 290x

I'm trying out various brands of 380x cards this week but form my estimation its not worth it to pay anthing more for the 380x at least for mining since it hashes only 5% higer than the 380 and uses more power basically a worthless card.   
full member
Activity: 189
Merit: 100
I have extracted a solo miner showed resolve, but the server node seems to be ignored, that is, the balls from the miner with chunks.

LOL true. I'm sorry man, just knocked this out blindly without access to an actual AMD card. For now, some further testing by others have indicated there presently no need to worry about allocation problems in the near future. I wil have to verify for myself to be absolutely sure though.

I'd could send you one of my 7950s if you want to pay for shipping i have a bunch laying around due to no motherboards to host them in.

This dag problem is getting huge for my my 900mh/s farm is down to like 700mh/s

The Dag problem is not a problem as it affect all the graphics cards. But I heard that it affects R9 380 less.

I keep hearing this as well, but i don't think I've seen enough data to be sure about this yet, or the reason why the 380s aren't affected. Is it the difference in memory types or what? Also what kind of difference if any does the trashing have on the 380 vs 380X?

Yes. We need more data to assess the situation. I am also interested in knowing the performance of 380 vs 380x.
full member
Activity: 146
Merit: 100
I have extracted a solo miner showed resolve, but the server node seems to be ignored, that is, the balls from the miner with chunks.

LOL true. I'm sorry man, just knocked this out blindly without access to an actual AMD card. For now, some further testing by others have indicated there presently no need to worry about allocation problems in the near future. I wil have to verify for myself to be absolutely sure though.

I'd could send you one of my 7950s if you want to pay for shipping i have a bunch laying around due to no motherboards to host them in.

This dag problem is getting huge for my my 900mh/s farm is down to like 700mh/s

The Dag problem is not a problem as it affect all the graphics cards. But I heard that it affects R9 380 less.

I keep hearing this as well, but i don't think I've seen enough data to be sure about this yet, or the reason why the 380s aren't affected. Is it the difference in memory types or what? Also what kind of difference if any does the trashing have on the 380 vs 380X?
hero member
Activity: 693
Merit: 508
I have extracted a solo miner showed resolve, but the server node seems to be ignored, that is, the balls from the miner with chunks.

LOL true. I'm sorry man, just knocked this out blindly without access to an actual AMD card. For now, some further testing by others have indicated there presently no need to worry about allocation problems in the near future. I wil have to verify for myself to be absolutely sure though.

I'd could send you one of my 7950s if you want to pay for shipping i have a bunch laying around due to no motherboards to host them in.

This dag problem is getting huge for my my 900mh/s farm is down to like 700mh/s

The Dag problem is not a problem as it affect all the graphics cards. But I heard that it affects R9 380 less.
legendary
Activity: 2408
Merit: 1102
Leading Crypto Sports Betting & Casino Platform
I have extracted a solo miner showed resolve, but the server node seems to be ignored, that is, the balls from the miner with chunks.

LOL true. I'm sorry man, just knocked this out blindly without access to an actual AMD card. For now, some further testing by others have indicated there presently no need to worry about allocation problems in the near future. I wil have to verify for myself to be absolutely sure though.

I'd could send you one of my 7950s if you want to pay for shipping i have a bunch laying around due to no motherboards to host them in.

This dag problem is getting huge for my my 900mh/s farm is down to like 700mh/s
sr. member
Activity: 438
Merit: 250
I have extracted a solo miner showed resolve, but the server node seems to be ignored, that is, the balls from the miner with chunks.

LOL true. I'm sorry man, just knocked this out blindly without access to an actual AMD card. For now, some further testing by others have indicated there presently no need to worry about allocation problems in the near future. I wil have to verify for myself to be absolutely sure though.
hero member
Activity: 616
Merit: 500
jr. member
Activity: 55
Merit: 1
I have extracted a solo miner showed resolve, but the server node seems to be ignored, that is, the balls from the miner with chunks.

Does it mean the etherminer is mining, but the shares are not recognized?
hero member
Activity: 616
Merit: 500
I have extracted a solo miner showed resolve, but the server node seems to be ignored, that is, the balls from the miner with chunks.
hero member
Activity: 693
Merit: 508
Binary is on the eth forum in mining section
I tried with different settings of chunks, 640, 660, these figures reduce hash rate about 3 times on R280x, R290. 6x280x give about 50 MGh. At the same time setting 1300 or more does not affect the speed, the speed becomes normal, about 150 MGh, and chunks 1300 give 150 MGh. Maybe I do something wrong? ....Before starting hash, miner writes that he can't create 2 block DAG file because it is blocked GPU.

Did your miner submit valid shares?
hero member
Activity: 616
Merit: 500
Binary is on the eth forum in mining section
I tried with different settings of chunks, 640, 660, these figures reduce hash rate about 3 times on R280x, R290. 6x280x give about 50 MGh. At the same time setting 1300 or more does not affect the speed, the speed becomes normal, about 150 MGh, and chunks 1300 give 150 MGh. Maybe I do something wrong? ....Before starting hash, miner writes that he can't create 2 block DAG file because it is blocked GPU.
sr. member
Activity: 438
Merit: 250
Binary is on the eth forum in mining section
full member
Activity: 189
Merit: 100
I just finished implementing the chunk allocation into my fork of ethminer.

https://github.com/Genoil/cpp-ethereum/tree/opencl-chunks

By allocating DAG memory in chunks (--cl-chunks ), issues with RAM allocation may be averted. A nice side effect of this may be (significantly) higher hashrates. Based on what I've seen from people using dagSimCL, --cl-chunks 640 yields quite good results. It may be however that there is a correlation between optimal setting of chunk size vs dag size.

I wrote this change without access to AMD hardware, so your mileage may vary. Don't bother trying this on CUDA devices, using chunks there only has a negative impact on hashrate.

  

Do you have instructions for building the problem. Do you have an exe version so that we can try.
sr. member
Activity: 438
Merit: 250
I just finished implementing the chunk allocation into my fork of ethminer.

https://github.com/Genoil/cpp-ethereum/tree/opencl-chunks

By allocating DAG memory in chunks (--cl-chunks ), issues with RAM allocation may be averted. A nice side effect of this may be (significantly) higher hashrates. Based on what I've seen from people using dagSimCL, --cl-chunks 640 yields quite good results. It may be however that there is a correlation between optimal setting of chunk size vs dag size.

I wrote this change without access to AMD hardware, so your mileage may vary. Don't bother trying this on CUDA devices, using chunks there only has a negative impact on hashrate.

  
newbie
Activity: 16
Merit: 0
Because of the drop of the hash rate. I decided to reduce the core clock frequency and keep the memory frequency the same. Is that a good idea?
member
Activity: 115
Merit: 10
Is there any news about the development of the etherminer so that it can cope with the larger DAG size. We are approaching 1280MB.

I have heard nothing.  I also tested this and found a problem at ~1280 as well.

I started looking on forums as I noticed a substancially drop off on the 7970 cards at ~1.2 GB.  

At this point my 280xs are down from 27 to about 24
and
At this point my 7970s are down from 22 to about 17 each (this was what supprised me and this problem is present on XFX, powercolor and one other)

This drop in performance seems to be larger than the expected drop

Oddly enough my 7870s seem to have suffered little if any performance hit and are still happy doing 15 same as at launch.

Edit my 7870s are the ghz edition, however, i also have a sapphire and a 7870 MIST (which is really a broken 7950) both of these are also unaffected.

Food for thought.

Do you find the drop during the test or the actual mining?

I am now dropping in actual mining on this hardware with the dag update at block 840000; the point being is my drop in hash seems to be more than predicted by the size of DAG increase.
sp_
legendary
Activity: 2926
Merit: 1087
Team Black developer
Let the dagger grow. The ether algo will be perfect for the botnets.
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