How to use multiple GPU on jminer



  • Hello,

    I was wondering what should I edit so that I can use 2 gpu's in jminer? I see in the settings file that I can choose between 2 gpu ID's (0 or 1) but is it possible to choose both of them?

    Thank you for the help.

    Cheers.



  • @pr0cesor afik jminer can only use 1 GPU currently.



  • @luxe could answer that question because he wrote it but i would assume manual configuration of several jminers to utilise the different gpu addresses. gpu plotter can display the physical addresses of your gpu's that can be used for several jminers configurations. never seen a need to do this however.



  • @pr0cesor Are you asking about this because you have two different account IDs that you are mining? If so, then opening two instances of Jminer will likely be the solution (create a duplicate of your existing Jminer folder, so that you have one more properties file where you can configure a new set of plot files to be scanned, and where you can configure new device IDs).



  • if that's the case all miners should be allocated to the same pool.



  • @Propagandalf said in How to use multiple GPU on jminer:

    @pr0cesor Are you asking about this because you have two different account IDs that you are mining? If so, then opening two instances of Jminer will likely be the solution (create a duplicate of your existing Jminer folder, so that you have one more properties file where you can configure a new set of plot files to be scanned, and where you can configure new device IDs).

    I have 2 gpu in SLI so in jminer is see that it chooses only 1 gpu.


  • admin

    @pr0cesor One jminer instance can only use one openCL device ... if you do not have massive capacity, the GPU is not the bottleneck anyway (you will not benefit configure a 2nd GPU cause drives can not deliver data fast enough anyway) ... if you have like lets say 400TB, you could try use 2 jminer instances both with own GPU ... not sure if the thread handling will work smoothly.
    Alternative you could try activate Crossfire/SLI ?! Not sure if that would work.



  • @pr0cesor said in How to use multiple GPU on jminer:

    @Propagandalf said in How to use multiple GPU on jminer:

    @pr0cesor Are you asking about this because you have two different account IDs that you are mining? If so, then opening two instances of Jminer will likely be the solution (create a duplicate of your existing Jminer folder, so that you have one more properties file where you can configure a new set of plot files to be scanned, and where you can configure new device IDs).

    I have 2 gpu in SLI so in jminer is see that it chooses only 1 gpu.

    I have never used SLI before. When they are connected in SLI, does the system see them as only one GPU? If yes, then maybe Jminer sees them both as only one device as well, so that you are using the power of both when you assign that one device ID. Like Luxe said you won't really need more than one instance unless you have very large plots, or if you have different account IDs and pool reward assignments.

    To get better read speeds of your plots, your plots should be optimized, and you should spread your drives out over several controllers (USB 3, SATA) so that you can maximize simultaneous reads and not get bottlenecked by one controller (if you have more than one).


  • admin

    @Propagandalf Not sure if openCL supports SLI, if yes there should be one 'master' GPU with 'slaves'. But seams that would not work ... http://stackoverflow.com/questions/3691460/does-glsl-utilize-sli-does-opencl-what-is-better-glsl-or-opencl-for-multiple



  • @luxe I read the posts in your link, and judging by that it seems like the 'workload must be manually split' between the different GPUs, hence SLI should not be used.

    @pr0cesor
    It seems like the only way you are able to utilize multiple GPUs using OpenCL is to not use SLI, and instead launch two instances of Jminer (if you really need to). As a comparison, I use three standalone MSI rx 470 8 GB gaming X cards to plot with using GPU plotter. Unlike Jminer, one instance of GPU plotter can use multiple GPUs, but I prefer to split and use one instance per GPU.


  • admin

    jminer would need a additional 'checker' for every openCL device ... not that big change in code ... but need to find time for it ... and in most cases it makes no sense anyway ... like i said before ... GPU is not the bottleneck. But this request came up earlier and it is still on my todo list oO.



  • @luxe Just to clarify: Did you say that Jmimer can handle two instances based on the same platform/device ID, but that thread handling might become an issue? I will have a scenario in about a month's time when I have three accounts with reward registration on three different pools that need to be mined from one machine with two rx 470 GPUs (no crossfire). The idea was to have three instances of Jminer, but where two of them link to the same platform/device ID. :)


  • admin

    @Propagandalf well it should be possible, guess threads are no issue, just ensure different instances not access the same drives :-) As long as CPU has not 100% load threads are no issue.



  • @luxe I see what you mean. :) Do you know if CPU gets harder or lighter load when plots are optimized? I still mean when using Jminer.



  • Hi guys,

    Thank u all for ur replay, unfortunately as suggested I tried to put the 2 gpus together in one SLI but the Jminer still see then as separate devices and Jminer only choose one of them always, in this case by default it chooses [0].

    Is the GPU here a big factor that would be a game changer in mining Burstcoin or not really?

    Will there be an advantage to have 2 gpu's working simultaneously in the future for Burstcoin mining?



  • @pr0cesor Hey there. Sorry if we weren't being clear, but Jminer uses OpenCL and therefore SLI will not work. So, the only current way of using two GPUs would be to not use SLI, and open two instances of Jminer where you modify one config file to use device 0 and the other config file to use device 1, but they should not be reading the same plot files.

    If you have many TBs of capacity GPU and Jminer will make quite a big difference in reading speed, but if you only have a few TB, you may as well use your CPU if you have a decent one.

    As far as I know using two GPUs for mining does not necessarily improve anything, since I think one GPU can handle mining pretty well on its own (if you have a decent GPU). On the other hand, when you are GPU plotting, having more than one GPU will greatly increase your plotting speed. As a reference I am able to plot 40 TB per day in buffer mode (unoptimized) using three MSI rx 470 8GB Gaming Xs, where one of them runs at half speed because it is also used for the monitor. When plotting with multiple GPUs you also need a good CPU, because the CPU is always involved in the process.



  • @Propagandalf Now it's clear, thank u for the explanation. Yes I noticed that plotting requires more gpu resources than mining.


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