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Poser - OFFICIAL F.A.Q (Last Updated: 2024 Nov 25 12:38 pm)



Subject: But I Thought Page Faults Were Bad?


nerd ( ) posted Mon, 16 September 2002 at 5:21 AM · edited Fri, 22 November 2024 at 3:56 PM
Forum Moderator

Now we know what it's doing the rest of the time. Please note that Poser has only been running for a bit over an hour. Humm, 20 Million Page Faults Per Hour. That's about ten times the number of pixels FireFly can render in an hour.


phoenixamon ( ) posted Mon, 16 September 2002 at 5:24 AM

YIKES! >:o Well now I know why it crashes so very often. Phoenix


ronmolina ( ) posted Mon, 16 September 2002 at 5:33 AM

Wow that is alot of page faults. I will monitor that today and see what I get. Ron


Little_Dragon ( ) posted Mon, 16 September 2002 at 5:53 AM

That's Poser 5, I assume. What is Poser 4's record?



kawecki ( ) posted Mon, 16 September 2002 at 6:21 AM

Poser fault or M$ Task Manager fault ?????

Stupidity also evolves!


dbutenhof ( ) posted Mon, 16 September 2002 at 7:26 AM

Page faults affect performance, but there's no relation between page faults and stability. They're only "bad" if they're unnecessary. Sometimes they're just unavoidable. 3D rendering usually requires a LOT of memory for geometry information and especially texture data. It's typically accessed in an irregular pattern -- which means that if you don't have enough "working set" (the physical RAM pages each application is currently allowed to use) it'll have to constantly move the data between RAM (working set) and disk (backing store).

That can really slow things down, since disk access is lots slower than main memory. Still, if that affects stability, then the stability in question is the OS, not the application. (Page faults aren't controlled by or even normally visible to the application.)

I notice that the display up in the first note shows the system has allocated about half of the system's 1Gb RAM. With any moderately complicated scene I'll bet Poser could easily use that much all by itself. Which also implies you might have had plenty if the system had allowed Poser to use the other half gigabyte.


Kiera ( ) posted Mon, 16 September 2002 at 10:53 AM

Page faults, as dbutenhof states, are normal. INVALID page faults, on the other hand, make your application or system crash. ;)


nerd ( ) posted Mon, 16 September 2002 at 1:53 PM
Forum Moderator

Yeah, page faults are part of life in windows, but 20 million in an hour? This systems has 1/2 GB RAM and two 1GB page files. If windows is "holdin back" memory just where do you kick it to get it to give Poser all it wants? Win 2K, P4/1.8, 512 RDRAM, two WD80 7200, ASUS P4TE


Kiera ( ) posted Mon, 16 September 2002 at 2:07 PM

file_23993.jpg

Try this.


nerd ( ) posted Mon, 16 September 2002 at 2:13 PM
Forum Moderator

I thought all that did was set the CPU priority.


Kiera ( ) posted Mon, 16 September 2002 at 2:29 PM

As far as I know there is no way in Windows to directly allocate memory to a given program.


dbutenhof ( ) posted Mon, 16 September 2002 at 2:29 PM

"INVALID page faults, on the other hand, make your application or system crash."

Well, yeah; but then they're GPC faults, not "page faults", and they don't get counted the same way! > "This systems has 1/2 GB RAM and two 1GB page files."

Ah; OK, I misinterpreted the summary. Looks in that case like you're probably using all your physical memory; but Poser only has about half of that. Raising the memory priority may well convince Windows to give that process "more than its share". Worth trying, anyway. Of course -- you might also consider buying another 512Mb RAM. It's not that expensive now, and well worthwhile.


Kiera ( ) posted Mon, 16 September 2002 at 2:32 PM

How do you raise the memory prioty in Windows dbutenhof? I thought you had to get one of those memory washers to deal with it.


nerd ( ) posted Mon, 16 September 2002 at 2:37 PM
Forum Moderator

RAMBUS is, and all the slots are full. "Memory Priority" Where?


dbutenhof ( ) posted Mon, 16 September 2002 at 4:21 PM

"memory priority"

Sorry; I'm not a Windows person, which is why I was able to guess wrong about the meaning of the summary information. I know a lot about virtual memory from my experience with UNIX kernels. (Poser is a hobby; I'm a UNIX system software developer in "real life".) The performance of Poser 5 has been a subject of several discussions recently here on Renderosity, though, and several people have claimed success with "increasing the memory priority". So I just repeated that. If that's wrong, I could apologize for passing it on without caveats, but there's not much point in that.

Perhaps those people were misinterpreting the significance of raising the "priority" (general purpose) of the Poser task. On the other hand, it's equally possible that Windows does give higher "memory priority" to tasks with generally higher priority. It'd make some sense, since "raising priority" is something one generally does for realtime applications, where response latency is critical. In conjunction with that, on UNIX, one typically "locks" the application into the working set (and the working set into physical memory). "Memory priority" would actually be a pretty good way to approximate some of that with less system impact.

In any case; as I said, it's worth a try.


timoteo1 ( ) posted Tue, 17 September 2002 at 1:13 AM

Actually, memory CAN be allocated to a specific program ... but the program has to support it, it can not be done in the OS, as far as I know. A lot of Adobe products support this (After Effects I know for sure) as well as both some Graphics Software (Picture Publisher 10) and sound mixing software I use. -Tim


mjtdevries ( ) posted Wed, 18 September 2002 at 4:35 AM

No. You cannot allocate memory to a specific program in windows. Windows will just give any program as much memory as it asks for. (Windows will keep a decent amount of memory for filecache and to keep important DLL's and windows code in memory). When you allocate memory in Adobe it only tells Adobe how much memory to ask from Windows. (That why you can limit the amount of memory it asks for to save for other programs, or even exaggerate so that no swapping is required when it needs more) A Page fault basically means nothing more then that Poser asked for a piece of memory that wasn't stored in RAM, but that was stored on the disk in the swapfile. When you see lots of Page faults, (a page is small, so if you need a couple of MB from the swapfile you quickly have lots of page faults) it means that Windows didn't have enough memory available in RAM to supply to Poser. Of course swapping is really slow, so it should be avoided if possible. Two remedies: 1) Buy more RAM. I'd advise to run Performance monitor in the background and measure the amount of memory poser wants. That way you can see how much RAM it asked for and how much you should buy to keep it happy... 2) Try to free up memory by closing programs in the background that use lots of it. BTW those memory cleaning tools you can find on the web DO NOT help for this. (If people want to know why, I'll be happy to explain it, but I don't think that that adds anything to this thread at this moment) Setting a priority only applies to the amount of CPU time a program receives when it has to share it with other programs. It doesn't do anything to memory. By default the foreground application will get a bit higher priority in windows. (Except in server versions)


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