Prime95 P-1 memory leak?

[TheMawn]

The computer I run P-1 on has two cores and 8GB of memory, of which 6 are allocated to factoring. For the most part, I stop Prime95 when I want to do anything with the computer since the 2 GB for everything else is pathetic at best.

Today I was setting up a video to play while I had a little workout and I noticed the first worker was doing stage 1 (at 40% which is ~7 hours in) and the second was doing stage 2 with 1200 MB.

I do on occasion continue running the P-1 if I am doing very lightweight tasks.

If two workers are sharing the 6 GB between them (i.e. they're both on stage 2) then the computer is on the very edge of being completely unusable, showing the very obvious symptoms of running low on memory. If one worker has all 6 GB, the computer behaves quite fine.

Today, the computer was unusable. The desktop had less than one frame per second, the task manager and Prime95 window both took ~10 seconds to open. Neither responded to anything for at least five seconds. Stopping the program took nearly a minute.

The task manager reported Prime95.exe using ~2500 MB. After closing, total RAM usage dropped by 1200 MB but remained more than 1 GB above where it usually sits.


I feel like this points to a memory leak... Yes, no?

Known issue?

One-time bug?

[lycorn]

Originally Posted by TheMawn

I noticed the first worker was doing stage 1 (at 40% which is ~7 hours in) and the second was doing stage 2 with 1200 MB.


The task manager reported Prime95.exe using ~2500 MB. After closing, total RAM usage dropped by 1200 MB but remained more than 1 GB above where it usually sits.

Something is not adding up properly in the figures above. The memory used by Stage 1 is normally negligible, so how come the total mem used is 2500MB when Stage 2 is only using 1200MB?
Also, it is a bit weird that Stage 2 is using only 1200 MB if there is so much more mem available.
That said, I suspect you had some process(es) other than Prime95 eating up their share of memory as well. When you checked Task Manager did you took note of the figure for the total memory in use? If it was approaching 85-90% its normal that the system become hard to use, but Prime95 is only using the memory it is allowed to do.
Don´t forget that some programs (IE or Google Chrome, for example) may take up considerable amounts of memory by spawning several processes with many windows opened.
And what about the video you said were setting up? Were you already tryimg to play it whem the PC became unusable?

[kladner]

Look for dllhost.exe in Task Manager and see what it is consuming. I recently started getting "almost out of memory, shut down Prime 95" warnings from Win 7 64-bit, on a system with 32 GB of RAM. This might seem like a P-1 situation, except that I recently changed over to running DC on the CPU.

It seems that recent updates, possibly to IE 10, caused a problem with generating thumbnails for videos, and possibly still images. Dllhost mediates this function, and it gets hung up consuming memory until there is no more. See these links-

https://www.google.com/search?q=dllh...ient=firefox-a

and particularly-

http://answers.microsoft.com/en-us/w...2-2bb6b566996d

Fix
"MS are aware of problems with certain chipset/ combinations and the KB2670838 update
They are also aware of problems with the IE10 install

They are working on both issues, and will update as and when they are satisfied that they have solved the problems.
The recommendation in the meantime is that if the update doesn't install first time, make sure it's uninstalled, and then hide it - Windows Update will unhide it when it is updated."

So Uninstall IE10 and KB2670838 update, hide them from auto updating when thy pop back up to be updated the problem should be fixed.

Proof that MS knows that IE10 has problems on some hardware platforms is here.

http://technet.microsoft.com/en-us/ie/jj898509.aspx

I took out KB2670838 and the leak stopped. This also seems to have rolled IE back from 11 to 9, which is fine with me as I rarely use Internet Exploder.

[TheMawn]

I'm thinking Windows detected 2500 MB were in use by Prime95 but Prime95 somehow "lost" 1300 MB to a memory leak and was only giving 1200 MB to the worker. No idea why it was only using 1200 MB of the available 6144. The memory usage does get up to 90% or so, but it only acts sluggishly when there's two workers using 3 GB each, or whatever.

When I finally killed Prime95, everything started working a lot better (but like I said, RAM usage was at least 1 GB higher than where it usually is when I stop Prime95). No other applications were running. As far as I remember, I had rebooted that computer and left it running Prime95 and nothing else for about a week.


I'll keep dllhost.exe in mind. I never use internet explorer either except to download Chrome


EDIT: I'll leave it running everything more or less the same way I did before and see if the issue crops back up. Right now, two instances of dllhost.exe are using 2MB each.

[kladner]

Originally Posted by TheMawn

[snip]
EDIT: I'll leave it running everything more or less the same way I did before and see if the issue crops back up. Right now, two instances of dllhost.exe are using 2MB each.

I does seem that your situation might be different. In my case, dllhost had sopped up something like 30 GiB, and I only got it back when I killed the process. At that point I had considerably more free memory than I usually see as Windows had kept stuffing the Pagefile until it hit the wall and started complaining.

[Batalov]

You may want to add these columns to the 'task manager' and check them out, the next time it happens (below). E.g. When NFS@Home's 16e siever's second instance of the siever was crashing soon after initialization (on a very large SNFS), it was easy to see that even though it claimed to use 1.1Gb memory, it was actually trying to use 2.6Gb per process or something like that. (This was later fixed, ...I think.)