Topic: Preventing 100% CPU usage? (Read 5326 times)

i have started a thread at amd dev forum - opencl section about the 100% cpu usage bug with >1 gpu installed. feel free to jump over there and post your support for this issue being addressed...

http://forums.amd.com/devforum/messageview.cfm?catid=390&threadid=153211&enterthread=y

I got some information from some other threads, e.g.: http://forum.bitcoin.org/index.php?topic=6188.60

As far as I know the problem occurs when:
a) more than one graphic card is installed
b) occurs with crossfire enabled and disabled
c) is particularly bad when only one cpu core is available
d) might be related to SDK 2.4 (in one of the other threads someone mentioned that this might not occur when SDK 2.1 is used, so you would need to use catalyst 10.4 as far as I know)

It seems that a lot of people don't realize that problem because they have multi-core cpu's, e.g. a six core cpu with 2 graphic cards would only use 2/6 => ~33% of the cpu usage, although the problem is the same.

I do have the same issue. I tried the SDK 2.1 alternative once, but got the same results - however, I didn't clean all drivers with drivesweeper so it might not be bulletproof - maybe someone can respond on that one.

Anyone ever tried winThrottle ? http://www.oldskool.org/pc/throttle
It seems to be an old software but was (besides affinity and granola) the only cpu throttling software I have found. Problem is you need to install the included drivers as a Windows device but Windows 7 doesn't let me (cannot add manually a device - maybe I'm just to stupid to find a way - do you know one on W7?). The idea would be to max the overall CPU usage to e.g. 20% (or lower). Even though mining software would still use those 20%, it would be far better. What do you think?

I'm having the same exact issue. I'll have to try the actual monitor plugged in. After that I'll also give linux a quick go. I have a live disc ready.

I only had a monitor hooked up to this machine when initially setting it up so all my numbers are coming from viewing VIA teamviewer.

One thing I've noticed about the 100% CPU utilization is that my GPUs are not always at 99%. I've seen them drop as low as 89% for a moment. Generally they bounce around from 95% to 99%.


Just some system info...
Sempron 140
6950 unlocked at 580/310 using Poclbm with flags -v -w 128 -f 2
5850 580/300 using phoenix with flags -k phatk VECTORS BFI_INT AGGRESSION=7 worksize=128
2 GB DDR2 GSkill ram (single stick)
950 watt PSU (800 sustained)
Windows 7 64-bit
CCC 11.6
SDK 2.4 (I believe thats the version that comes with CCC 11.6)

tried f1 and f60. regardless its at 100%.

when i had one card plugged into a digital monitor, <3% usage.
went dual card and used digital monitor, <3% usage.

installed dummy plugs in both slots, 100% usage.

im half tempted to plug a digital monitor back in and see if it goes back to <3%

I rarely see *any* CPU usage with single 6870 with a Pentium 4 CPU with Windows 7. In fact the system is used for basic graphics work in a production environment (Illustrator, Photoshop, etc.) and runs GUIMiner 24/7. The only time Windows Task Manager shows any CPU usage (1% for a half second) is when GUIMiner reports a share accepted.

I'm getting about 290 Mhash/s from this card, although that diminishes slightly when graphics work is being performed (even moving the cursor.) Al tasks seem to have priority over GUIMiner.

I'm just running the suggested "-v -w128" flags.

Switch to Linux! You have Windows and ATI card, that will require 1 cpu core per gpu! That a know bug!

Have you alrady tried lowering agression in phoenix and using -f in guiminer right?

aside from the extra heat and increased power used.

You can set a lower priority on the process, then you don't need to worry if it use 100% CPU.

Any decent operating system will have a tool such as "nice" which can be used to prevent programs from using CPU time if other programs want it (or you could give programs priority over others). I'm not sure if the GNU nice (which will come with virtually any Linux based OS) allows you to set a maximum CPU usage regardless of other programs. But I don't know why you'd want to do that anyway. If you aren't using the computer, just let your miner run free...

How many cores do you have and what are you running? Perhaps you have a multi threaded multiple core system that's only maxing out one thread?

like i said, using OpenCL miner under guiminer with an actual digital monitor plugged into card#1, it was <10% CPU.

and the type of processor, im highly doubting has anything to do with it. ive heard so many people talk about setting affinity to a single core, the sempron 140 is not a multi core processor.

not that it makes MUCH of a difference, theres really no difference in my GPU temps. 74*c and 75*c. only real downside is the extra 25watts the CPU uses (15w idle, 40w load)

Thats odd.  Mine doesn't use up hardly any of the CPU.  It appears to only be affecting those who have single core Semprons

just got a rig going. these are my results.

Phoenix = 100% cpu usage. Regardless it would seem. Using Phatk kor Poclbm kernel

OpenCL = <10% cpu usage when I had dummy plug on card#2 and digital monitor on card#1
OpenCL = 100% cpu usage with dummy plugs in both cards.

Odd. I literally just unlugged the LCD, replaced it with a dummy plug, booted the system up and CPU usage is 100% with OpenCL now. No real change in Mhash using OpenCL.

AMD Semprom 140
2gb Mushkin (1stick)
5830x2 at 880/300 pushing 510~Mhash/s across 4x miners (backup pool on each card with -f60, main pool -f2)

You have a 4 core CPU so bitmining is using 100% of 2 of your cores. The new GUIminer sets the affinity to 1 or 2 so at least it is not using all 4 of your cores.

Anyone have an answer to my question?

Are you sure it is the actual miner which is taking upp all that CPU?
I ran GUIminer with my two 5850s on my x4 965BE CPU with three cores disabled and downclocked to about 2.5Ghz just to see what poer usage i got to, but it still only used like 25% of the cpu. I am watching my miner now via teamviewer, it is 50% total CPU, with system idle process having about half and poclbm having a constant 25%...

I can note that I am able to run 720P video from my CPU while mining at full speed without losing hash.. I also have utorrent and some othe rstuff running in the background without affecting the CPU badly.

Is there any miner, flag, tool or OS that will prevent 100% CPU usage while using 2+ cards bitmining?

From what I have read this occurs on every OS, across multiple miners, with and without Crossfire enabled. Setting "affinity" partially works, but still affects hash rate.

On a single core, unlockable Sempron, this is killing my hash rate by about 15-20%.

So has anyone found a solution?