Problems with dual-core

KimB

Legend
Just wanted to post about a couple of pretty significant problems that I've had with dual-core.

The first problem, which I have yet to solve, is that I can't seem to download anything under Windows 2000. Even small files get corrupted on download, and I've tried using a variety of download programs. Downloading under Linux works fine.

The second problem was under Linux, but fortunately I have solved this one! I just thought it was a rather interesting problem anyway :) The issue was that after time, the clock would slowly start to get out of sync. If the computer was left on long enough, the clock would get faster and faster. One morning I woke up and the computer's clock was two days ahead, and a minute was passing about every ten seconds. This was rather interesting as I couldn't double-click anything, the typematic rate meant that I had a very hard time typing anything (anything more than the shortest tap would result in keys repeating), and the (passworded) screensaver would come on if I just took my hand off the mouse for a few seconds.

This was a rather extreme situation, but even after just having my computer on for 30 minutes or so the clock would be a few minutes ahead, enough so that any online games that I was playing would have totally f'ed up client-side prediction, dramatically reducing playability.

As it turns out, I think the problem was in the powernow-k8 driver, and a fix has been rolled into the 2.6.13 kernel. So all fixed now!
 
Sometimes when I log into EQ2 with my 4800+ my client is accelerated. Day/night cycles take just a minute or so each, and I can sprint across all of TS in about 5 seconds. My wife came into the room and asked if that was my new master spell making me sprint like the Bionic Man. I'm half-tempted to use Fraps to make a movie of it.
 
John Reynolds said:
Sometimes when I log into EQ2 with my 4800+ my client is accelerated. Day/night cycles take just a minute or so each, and I can sprint across all of TS in about 5 seconds. My wife came into the room and asked if that was my new master spell making me sprint like the Bionic Man. I'm half-tempted to use Fraps to make a movie of it.

Holy shit..I had an image in my head of your character moving at that speed..you really need to make a movie of it. Do other online users see you move at this speed? You should harness the power and use it for good! or :devilish:
 
John Reynolds said:
Sometimes when I log into EQ2 with my 4800+ my client is accelerated. Day/night cycles take just a minute or so each, and I can sprint across all of TS in about 5 seconds. My wife came into the room and asked if that was my new master spell making me sprint like the Bionic Man. I'm half-tempted to use Fraps to make a movie of it.
Haha, that's hilarious :)

But due to the download issues I've been having, I haven't been able to even get the game started. But now I've finally decided to give it a go under Linux with Cedega, so we'll see how that goes.
 
My biggest problem with dual core so far has been getting one.
bleh2.gif
 
I've heard of other people have big timing problems on Dual Core AMD64s.

No idea on what the problems are
 
Colourless said:
I've heard of other people have big timing problems on Dual Core AMD64s.

No idea on what the problems are
Well, actually, as I was researching my clock issues, I found a number of people with dual-core Intel processors reporting similar problems. It's most likely a question of either processor support or assumptions made about which order things complete in a multithreaded environment.
 
Chalnoth said:
Haha, that's hilarious :)

But due to the download issues I've been having, I haven't been able to even get the game started. But now I've finally decided to give it a go under Linux with Cedega, so we'll see how that goes.

Wow, I can see why developers aren't overly happy about going multi-core.
 
I've had my 4400+ for some time now and haven't had any issues either with 32 & 64 bit Linux, 64 bit FreeBSD or 32 & 64 bit XPs. No time problems, download problems, game problems, ... (knock on wood...)
 
I believe Win 2K installs different kernels dependent on the cpu count at install time.

So you'll have to reinstall.

Using XP on a 4400+ with no problems.

Cheers
Gubbi
 
Gubbi said:
I believe Win 2K installs different kernels dependent on the cpu count at install time.
It does, but there is a help page on Microsoft's site on how to change it (thanks goes to Colourless for that info, in a previous thread). Without the change, the OS won't even recognize the second CPU. It is possible that there was an issue here, but I'm being lazy about reinstalling Windows at the moment (I'm just going to stick to Linux for the time being). But I think I'm going to have to switch back to Windows before too long as I'm going to want to do some more testing in Windows with my new hardware, I'm sure.
 
Chalnoth,

if the drudgery of installing all the software after the windows install, why not simply try a repair install? Should keep everything intact software/data wise.
 
Well, I'm not sure the repair install does anything but make sure your files aren't corrupted. And I've always wondered whether or not it messes with updates to Windows.
 
I remember having to reinstall updates, though since they still existed on the HDD, I didn't have to download them once more. Which was nice.
 
By far the biggest problem is the process scheduler in Windows (XP). It's fscked.

Games (and single threaded apps) actually runs slower because the scheduler bounces a process back and forth between the two cores. The game runs a timeslice on core 0, then it gets scheduled to run a timeslice on core 1; So now the game/app. has to fetch all data from the caches of core 0. Then it gets scheduled to run on core 0 again.

The end result is markedly lower performance, choppy frame rates (experienced in HL2 and CS:S).

So you have to pin down the game/app to run on one core using the task manager each time you've started up the game/app, a complete PITA.

But wait, it gets worse.

Not only is one process bounced back and forth, but you can risk two processes being bounced back and forth as well.

Running two instances of sciencemark's MolDyn I've experienced timings for a default run to vary from 71 seconds to over 110 seconds. The second I pin down the processes to run on their own core the time is consistently 71 seconds.

Reading reviews around the web, this seems to be a common pitfall. Often the 2.4GHz X2-4800 runs single thread apps slower than the 2.4GHz 4000+, something that should never happen, I'm guessing these apps are bounced back and forth between the two cores.

No wonder game developers are apprehensive about going multi-threaded, and those that do see performance come and go.

A final note to MS would be: GET IT SORTED

Does anyone know if there's any better affinity controlled process scheduling in XP64?

Cheers
Gubbi
 
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Chalnoth,

What are your system specs (mainboard/chipset)? Did you install the AMD Processor Driver (here)? Are you, perhaps, using an Nvidia chipset with the 6.66 drivers?

I remembered seeing this issue reported before so I did some digging and found this thread at HardOCP: Hardforum Thread

EDIT: Just realized you are using Win2k and that doesn't have a listed driver at AMD's site. I am not sure then, if some had network corruption (due to affinity contention) that was fixed with a processor driver update, but one is not available for your OS... Then again, it seems others are not having the problem (but it's hard to tell if they are all using the AMD driver). Have you tried re-installing the processor driver from Microsoft? Are you using Cool n' Quiet (tried disabling that?)? Oh, and I should have mentioned BIOS updates. Double-check to make absolutely sure you have the latest for your mainboard.
 
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Well, I'm sure that the network corruption was a network driver-related issue, as since I'm now on a wireless network it's currently not a problem. But I did notice the updated powernow driver on that site for Linux, going to try to see a bit later if that helps fix my Linux issues.
 
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