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Massive jitter on newest hardware

Posted: Mon Jan 14, 2008 12:32 am
by KnottyMan [ILF]
My "old" system was an Intel 975x chipset with an E6600 (2.66GHz dual core/800MHz fsb) processor, Nvidia 7950, 4Gb of DDR2/800 running WindowsXP 32 and Ubuntu.

Under Windows, I had to set the process affinity to a single cpu otherwise jitter was very high but after that BZ plays fine. Standard dual core stuff...

New system is an Intel P35 chipset with an E6850 (3.0GHz dual core/1333MHz fsb) processor, nvidia 8800gts, 4Gb of DDR2/800 running WindowsXP 32, XP64, and Ubuntu64.

The weird thing with the new system is I have to run with the affinity set to both cpu cores otherwise the video is very jerky. Jitter is high no matter what.

All drivers are the latest, bios is the latest, etc. Network traffic is nil verified by ntop at my gateway.

I'm thinking it's got to be a hardware feature as it's also affecting Linux jitter as well.

Anyone else running on this hardware and finding this behavior?

Posted: Mon Jan 14, 2008 1:17 am
by sebkac
can't comment on that specific hardware, but in the past, I've problems with the on-board nic, or network card, on a new pc.

I ended up plugging in an older network card and that took care of my issues.

just a thought

Posted: Mon Jan 14, 2008 3:52 pm
by KnottyMan [ILF]
Yeah, but this is an Intel nic. The Pro1000 line is not some PHY'd Realtek or SiS memory sharing chipset... I can get 40MBytes/sec rsyncing. Also, the 975 chipset board had an Intel nic and with the same driver.

Posted: Mon Jan 21, 2008 7:58 pm
by Sky King
I have no answer, but, I am a bit puzzled by the jerky video when running single-core. Was this a result of network jitter, or was your frame rate tumbling?

I would think based on your iron that you should see CPU utilization under 20-30 percent even if single-cored. If you are set to single-core, and you are seeing very high utilization on the CPU, you may have the same CPU-offloading problem I had on my previous HP laptop:

On that laptop, I had to be very careful about my graphics settings. I don't know if it was BZ, or my GPU drivers, but someone was making decisions for me behind my back that were just the opposite of what I expected.

When I had most of the graphics settings maxed out, I got pretty good performance, and the GPU was doing all the heavy lifting. If I set some of them lower, like setting quality to medium or low, then my CPU maxed out and my GPU sat almost idle. Someone was deciding "hey, I don't need the GPU to do this, so I'll put it back on the CPU, and my CPU couldn't handle it.

When you said you had bad video jitter, it got me wondering if you meant bad video performance, or if you meant that your network was so bad it was causing problems on screen.

Posted: Tue Jan 22, 2008 4:14 pm
by KnottyMan [ILF]
Hmm, guess I need more investigating. Feels like video performance though.

Posted: Thu Jan 24, 2008 3:16 am
by KnottyMan [ILF]
So a format and reinstall of xp32 with minimal drivers.

Server ahs3 Rouge Wars Battle Cry
Multi core affinity ~1500fps 135ms 12 jitter Smooooth video
single core 160-175fps 160ms 15-20 jitter jerky as all get out with a half second of smooth thrown in every once in a while.

Posted: Fri Jan 25, 2008 11:49 pm
by Sky King
KnottyMan [ILF] wrote:Multi core affinity ~1500fps 135ms 12 jitter Smooooth video
single core 160-175fps 160ms 15-20 jitter jerky as all get out with a half second of smooth thrown in every once in a while.
Well, herein lies my concern. The difference in frame rate should be slight if your graphics card is doing the work. The fact that your frame rate is almost 10x higher when dual cored leads me to believe that your main CPU is doing all the lifting and your GPU is just sittin' around loafing. Your CPU has other stuff to do so I wouldn't expect it to be able to maintain those kinds of video rates.

Posted: Sun Jan 27, 2008 3:06 am
by KnottyMan [ILF]
As a non developer type person, where lies the problem then?

I've installed this system just like all my other systems. WinXP, Intel inf update, intel sata drivers, nvidia drvers, sound drivers, BZ.

I updated to the absolute latest BIOS, no help. The very opening screen says it's an 8800gts, sse2, PCI. Now the PCI interests me as when we all had AGP it would say so. But now we're back on PCI-e cards, or at least I am with this system... Could it not be optimized PCIe driver? Guess I need some other type of game to check speed there.

Linux seems to be affected too though so maybe it's just chipset hardware trickery?

Posted: Mon Jan 28, 2008 11:08 pm
by KnottyMan [ILF]
In windowed mode watching task manager, sure enough, 60-85% cpu. When I minimize the app, one core goes to nothing the second core is pegged.

Guess I'll try some beta or older drivers...

Posted: Tue Jan 29, 2008 1:50 pm
by anomaly
You should try this with other 3D games or applications. There are reasons that BZ may be doing this other than just your nvidia drivers. The way BZ is built (threading or not) can also affect the performance. Sometimes windowed mode uses more resources than fullscreen.

Minimizing should should stop sending output to the display. That behavior above is just not right. Trying other apps may help to determine if it is BZ or your graphics drivers.

Also letting the OS determine the CPU scheduling is usually the better option, unchecking the CPUs in the Windows XP Processor Affinity dialog.

Not sure how much you know about processor scheduling but here is one explaination:

BTW are you using taskset to set CPU affinity on linux? If not try "man taskset" for some info on the linux scheduler.

Good luck.

Posted: Thu Jan 31, 2008 12:31 am
by KnottyMan [ILF]
Yeah, I have super old 3d games - I really only play BZ as of late - so I'm looking for other demos.

I found on my previous machines, AMD x2 3800, that I had to set the affinity to a single core, otherwise it was horrible performance. I assmued that I had to do the same thing, that it was a crappy windows implementation and that the process was hopping cores and generating latency/lag.

However, on my Intel C2D/680i chipset, I don't have to.

Weird. More testing required.

Posted: Sun Feb 10, 2008 6:56 pm
by KnottyMan [ILF]
I'm using the task manager in Windows to set affinity because on my x2 it was the only way to get playable output. Figured it was an overall Windows thing as others had the same problem with other games and the affinity was the solution.

Portal First Slice uses all of one core, second core is practically nothing. Smooth video. Not a network game so it's kinda hard to see if it induces lag.

Tried BZ 2.0.8 and same effects.

Soccer server, 1500fps, 130-150ms, +20 jitter, full cpu util.

Trying old nv drivers and beta drivers next.

Posted: Sun Feb 10, 2008 7:34 pm
by KnottyMan [ILF]
Talking to myself again... oh dear. :|

nvidia 158.27
Grand hustla server
650fps, 40-60ms, 56 jitter, pegged cpu0

171.21 beta
560 fps 40-60ms, 17 jitter, cpu0 ~50%, cpu1 ~20%

Posted: Mon Feb 11, 2008 11:52 pm
by The Red Baron
KnottyMan [ILF]
about the PCI bios reference - have you checked your bios settings to make sure that the primary Graphics adapter is set to PCI-E (if you such a setting. Some boards have them, some don't)

I have a very similar setup. only its an x38 chipset, e6750, and HD3850 on vista x64. My fonts in bz are all garbled - but video performance is just fine. I tested with affinity set to both cores and to single cores. Performance stayed the same.

I'd be surprised if your mobo default to PCI as the bus for you video adapter, but still, Double check the bios.

Posted: Tue Feb 12, 2008 2:38 am
by KnottyMan [ILF]
nvidia control panel says pcie x16

Posted: Tue Feb 12, 2008 7:23 pm
by macsforme
When you first start the game, the console should have some video card information in it. What does it say?

Posted: Tue Feb 12, 2008 11:01 pm
by KnottyMan [ILF]
KnottyMan [ILF] wrote:The very opening screen says it's an 8800gts, sse2, PCI.
Last night I did a format/nlite install since I was getting tired of messing about with F6/intel ahci drivers.

I was able to play with +1 jitter! I trimmed out a bunch of stuff from XP and I also left vsync on so I'm only at 60fps (which really doesn't matter to the human eye as long as it's above 30...) so I don't know if it's the vsync, or some service I happened to trim out.

Posted: Wed Feb 13, 2008 2:45 am
by KnottyMan [ILF]
Not vsync, got 600fps and still +1 jitter, most I saw was 110ms, 3 jitter on king of the hill.

Posted: Wed Feb 13, 2008 10:49 pm
by macsforme
1ms jitter could easily be your connection... I'd say that's quite normal.

Posted: Thu Feb 14, 2008 4:56 am
by KnottyMan [ILF]
Right, but this is after major hoop jumping. I had to make an nlite install of windows trimming out a bunch of stuff that I normally turn off anyway, but there's something else that nlite did to make BZ work ok.

If I just do a plain XP install, I get jitter in the 10-60 range!

There's too much to list here of what I did. but nothing too radical really. QoS off, firewall off, trimmed out a bunch of languages, set user options.

That's why this is so weird, I've never had to do this on previous hardware. BZ just needs opengl really. Right now CPU utilization is pegged though. Didn't think that something like BZ would be all that difficult a cpu to deal with.

Posted: Thu Feb 14, 2008 5:18 am
by blast
BZFlag will try to run as fast as possible, so that's why it's using all the CPU power it can.