Bitcoin Forum

Bitcoin => Mining => Topic started by: Capitan on June 14, 2011, 03:10:47 AM



Title: Phoenix using 100% CPU
Post by: Capitan on June 14, 2011, 03:10:47 AM
I'm on W7x64, Stream SDK 2.4, and latest ATI drivers. Each instance of Phoenix uses up 100% of a CPU core. Are there any open source miners that don't hose the CPU (I know that it's not Phoenix's fault, it's something to do with the latest ATI drivers also assigning OpenCL work to the CPU in addition to the GPU, right?).

What is the workaround? I'd rather not change the driver edition if there are other options.


Title: Re: Phoenix using 100% CPU
Post by: innervisi0nn on June 14, 2011, 03:22:19 AM
same thing on all 3 machines here..100% cpu by phoenix


Title: Re: Phoenix using 100% CPU
Post by: muyoso on June 14, 2011, 03:25:39 AM
You sure you guys are not CPU mining with phoenix?  No 100% usage here.  Not even 5% usage.

Make sure to put DEVICE=1 as a flag.


Title: Re: Phoenix using 100% CPU
Post by: Coinbuck @ BTCLot on June 14, 2011, 06:49:30 AM
Same thing here, going to try the last flag.


Title: Re: Phoenix using 100% CPU
Post by: CptHook on June 14, 2011, 08:29:39 AM
As far as i have understood, lurking these forums, it is a feature in the ATI driver that allows the GPU to use CPU processing poser when the GPU is at a high load (to allow for >100% GPU usage, so to speak). This feature, when combined with bitcoin mining, will cause each GPU to use 100% of one CPU core (if you have 3 GPU's and an 8 core CPU you will be using 3 of the CPU cores, or 37.5%).
So far there is no way to reduce this load on the CPU, except for setting the affinity of the phoenix processes (or m0mchil, for that matter). If you set all the processes to the same CPU core, only this core will be at 100% load, with no significant reduction of hashing power (taking the example from before you would go from 37.5 to 12.5% CPU load).

The way you do this is to locate each individual process in the task manager. If you right-click a process you can choose 'Set Affinity'. By default this will be set to '<All Processors>'. I guess the rest is pretty selfexplanatory - just set all of the processes to run on the same core..


Title: Re: Phoenix using 100% CPU
Post by: Capitan on June 14, 2011, 08:22:22 PM
Just runn
As far as i have understood, lurking these forums, it is a feature in the ATI driver that allows the GPU to use CPU processing poser when the GPU is at a high load (to allow for >100% GPU usage, so to speak). This feature, when combined with bitcoin mining, will cause each GPU to use 100% of one CPU core (if you have 3 GPU's and an 8 core CPU you will be using 3 of the CPU cores, or 37.5%).
So far there is no way to reduce this load on the CPU, except for setting the affinity of the phoenix processes (or m0mchil, for that matter). If you set all the processes to the same CPU core, only this core will be at 100% load, with no significant reduction of hashing power (taking the example from before you would go from 37.5 to 12.5% CPU load).

The way you do this is to locate each individual process in the task manager. If you right-click a process you can choose 'Set Affinity'. By default this will be set to '<All Processors>'. I guess the rest is pretty selfexplanatory - just set all of the processes to run on the same core..

This assumes that i just run the miner and leave it, trusting that it will not crash. Every time the miner is restarted i would have to set the affinity, which is not practical. Is there a way to launch an app from the command line, and tell windows which core to "prefer" for that process?


Title: Re: Phoenix using 100% CPU
Post by: innervisi0nn on June 14, 2011, 08:48:48 PM
I think it's just windows prioritizing the processes. I'm not new at mining, device=0/1 is set.
I am also not the only one seeing 100% cpu usage. Bunch of my buddies see the same thing, only with PHOENIX though, not with guiminer.


Title: Re: Phoenix using 100% CPU
Post by: shackleford on June 14, 2011, 10:09:58 PM
I use " /affinity 1 " in the launching batch file for the miners (windows) this forces the process to be run on one core. Speed is not effected but it does let the CPU throttle down the other cores for wattage/heat benefits (If using a multi core).