Defiler

Terrible SCSI performance in Windows XP

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Dude. I'm just comparing identical hardware/filesystem in WinXP vs. Win2k. There aren't many variables left, other than the OS. ;)

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Dude. I'm just comparing identical hardware/filesystem in WinXP vs. Win2k. There aren't many variables left, other than the OS. ;)

Yes, you've done a great job of bounding the tests. Some of those contributing to the thread haven't, as they either don't have both OS's installed, or haven't otherwise properly bounded the tests.

We're on the same side here. I'll finally contribute hard data tonight.

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I don't think this is merely a benchmarking artifact.

I used Total Copy to watch the transfer speed as I copied a 270MB file.

From X15-36LP to WD 1200JB: 37MB/sec or so

From 1200JB back to X15-36LP: 12.5MB/sec or so

Seems like the performance problem is "real", not just an ATTO issue.

Hmmm...

This isn't as clear to me that it is demonstrating a performance issue (I'm still catching up on the older parts of the thread).

What's your cluster size on the 1200JB and the X15-36LP? Is the file system empty on both?

Thanks in advance for the information, btw. I'm just trying to sort apples from oranges.

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Unfortunately, I do not own a copy of Win2k, nor WinMe, nor Win98, to properly compare data. I could have tried WinNT or Win95, of course, but installing those with an existing WinXP installation can be a pain. The latter is not an upgrade, either, so I can't readily revert. And that also shows, by the way, that I can't easily escape the performance issue by "going back" to Win2k.

In any case, I'm using the default NTFS cluster size, if that info helps any.

Leo

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What's your cluster size on the 1200JB and the X15-36LP? Is the file system empty on both?

Both drives are NTFS, each has about 1.5GB of data on it. Default NTFS cluster size.

The X15-36LP is formatted in the same manner that it was for Win2k (though I did reformat it before the XP install.)

I get the same results on the FAT32 SCSI drives connected to the machine, so it doesn't seem to be NTFS-specific.

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I can only give my word as far as WINME is concerned in my case where ATTO produced very good results on the same config. I don't have any screenshot ready and ME is not in this machine any longer. I fear i don't have the resources for a new installation these days.

As far as XP is concerned i provided 2 screenshot where the only constant is the drive (Atlas 10KIII) and the OS. I did not even put my hands on the second system while the person who owns it can perfectly be considered as a reliable source. I don't think that the matching (low) results are a coincidence. I don't think that low writes & low reads rather than low writes only invalidates the fact that we are discussing about the same issue.

.. and by the way, leo was the first who posted about this particular problem in the forum. I certainly would not question the fact that he, who is a long time member, is dealing with the exact same problem.

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.. and by the way, leo was the first who posted about this particular problem in the forum. I certainly would not question the fact that he, who is a long time member, is dealing with the exact same problem.

That doesn't matter really. And, after all, there is still a possibility that we might be talking about different problems with similar symptoms.

I believe I forgot to mention that my partitions are certainly not empty. One is one-sixth full, another one is one-third full, and two are about half-full. I defragment them periodically.

Leo

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I switched back to Win2k Pro(SP2).

Previous benches were:

Atto averages write 40,000 read 10,500

With win2k

Atto averages Write 36,000 read 37,000

Same configuration, different operating system. Now this could simply be a fault with ATTO. HDtach results (I don't remember them right now) were considerably better with Win2k Pro.

I'm running an adaptec 39160, Atlas 10k II, Abit kt7a

Note: I just picked up a 10k III - woot.

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Let's see if this BBS will let me reply (I spent about 20 minutes trying to reply multiple times last night. The software is Beta, and it shows).

Under XP, with my slow Adaptec 2940UW, I got 16MB/sec transferring files to an empty SCSI disk (228MB file transfers) as measured by stopwatch. That's GOOD performance for UW SCSI.

IOMETER confirms this with great performance as well.

ATTO shows that my SCSI stinks:

xp_ntfs.GIF

Right now, I don't trust ATTO. Everything I try says SCSI is fine under XP. Except ATTO.

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Eh? Your ATTO graph looks reasonable to me.

????

Under Win2K, Atto will benchmark the same system as having writes at 90% or better of reads, for all block sizes. Take a look at the 32K and lower block sizes. Under Win2K, at ALL block sizes, the write and read performance is nearly identical.

Leokor is seeing something different. He hasn't been able to check Win2K, so he isn't claiming a Win2K vs. XP disparity. I saw some of his benchmarks under IOMETER, and they were horrible performance at all block sizes.

Now go back and look at your graphs from ATTO. Essentially identical to mine, but they scale to UW-2 or SCSI160 rates, In other words, as your block size grows beyond 32K, your performance delta between writes and reads drops.

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Bill,

Your ATTO graph looks more like Laurent's than mine or Defiled's. Which means we might have different problems. Ours might be real, as indeed shown by the IOmeter results I sent you last night. But then, it might not, after all, be blamed on Windows XP...

Leo

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Bill: Check out my original screenshot in this thread. Even at the largest blocksize, I'm only getting 12.5MB/sec writes. Your old UW rig is outperforming my X15-36LP.

Anyway, tonight or tomorrow I'm going back to Windows 2000, so I'll do some more "Stopwatch" testing. I suspect everything will be back to normal.

Maybe WinXP SP1 will fix this.

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Bill: Check out my original screenshot in this thread. Even at the largest blocksize, I'm only getting 12.5MB/sec writes. Your old UW rig is outperforming my X15-36LP.

Anyway, tonight or tomorrow I'm going back to Windows 2000, so I'll do some more "Stopwatch" testing. I suspect everything will be back to normal.

Maybe WinXP SP1 will fix this.

Yeah, your 29160 looks bottlenecked at 12MB. That's a different sort of problem (a very REAL and important one!) than the poor-perfmance at low blocks that your Tekram test showed.

I guess what we're seeing here is a mix of issues:

1)ATTO shows low write performance at low blocks for SCSI writes, but writes start to acheive performance on par with reads as block size increases. XP only, not Win2K. This issue is NOT reproduceable with other tools.

2) Some people are seeing performance bottlenecked at other throughputs. Leokor saw a really low figure, Defiler saw a bottleneck at a higher number.

Since not everyone is seeing those issues, I tend to look for things like drivers specific to your setup, or termination/cable issues (which won't go away with an OS change), or plug-and-play issues.

With the latter, maybe Win2K is doing a better job of making sure your Adaptec doesn't share a resource (like an IRQ) with another PCI hardware. I'd compare the resources used by all hardware (IRQ, etc.) between Win2K and XP. If you notice a difference, try to force them to be "the same", and see if performance changes.

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What's the Seagate 118202 ? XL, LP, 9LP etc ? I could not find it in the drive database.

ST118202LC. Cheetah 10Krpm, 1.6" drive, 18GB

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can this be related to drives that are partitioned?

I'm about to do a clean install of wxp on my 39160 / X15 rig tonight, and the first thing i'm going to run is ATTO.

I just checked under winME that the read / write numbers are good and performing well.

I'm going to install XP on my X15 as one 18GB partition (NTFS) default cluster size.

System:

P4 1.5 Ghz - i850 - RDram - 39160 > original X15 + 2 X IBM 120GXP on primary and secondary IDE channels.

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sxc: If you could run ATTO on it before you partition it, that would be cool.

Otherwise, I'm not sure what you mean. Heh.

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This might be unrelated, but who knows... When running the MemTest86 utility, I found a block of memory consistently giving out errors for different patterns. What was happening is it kept offsetting the correct values by 00020000 (that is, if the correct value were 10000000, it would become 10020000, if it were 00000000, it would become 00020000, etc.). The faulty address is at 033076a0 (at about 51MB point), and belongs to the range of memory addresses allocated for the system board.

I wonder if it could be affecting the PCI bus in some subtle way... I would have to find out which memory stick is responsible, and retest without it. But I might not have time to do it soon enough. Certainly, not today.

Leo

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This might be unrelated, but who knows... When running the MemTest86 utility, I found a block of memory consistently giving out errors for different patterns.  

<snip>

I wonder if it could be affecting the PCI bus in some subtle way...  

Subtle... no... affect it badly, YES! I think you are on to something here. Keep us posted.

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well after reading this thread I was a bit hesitant to DL atto and confirm the sluggish behaviour of XP

(as llong as I don't know I don't have a prob right?)

and my enterprise 10K had 87 KB/sec reads in the small block area and topped out at 8 MB/sec, reads were alot higher......no picture as I was too pissed to save any result (some I don't ever want to see again)

so I rolled back to W2Kprooem and reads are back in the 27MB/sec range.

too bad, I actually like cleartype and some of the gui enhancement (I never thought I would say that) I like the automatic time sync.. whatever, I'll try in about 6 months IF MS releases SP-1 in time, well we'll see.

I wonder why this poor SCSI performance is almost unnoticed on the internet as I can't really find any other sources than SR

greetz, Erik

before

enterprise 10K on 2940u2w on XP

after

enterprise, blablabla on W2Kpro

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Subtle... no... affect it badly, YES!  I think you are on to something here. Keep us posted.

Heh, this would mark the second memory stick failing in the same system. The previous one was from Crucial, but it was failing much more badly and much more obviously... This one is from Mushkin. Why am I so unlucky with memory sticks? :) And to think, they're all brand name and all...

Leo

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I wonder why this poor SCSI performance is almost unnoticed on the internet as I can't really find any other sources than SR

After a few phone calls, I've finally driven the Microsoft support guys to reassign my issue to their research team. I should get a call from the big guns in a couple of days.

Leo

P.S. By the way, did you know why SP1 for XP is delayed to September? It was meant to be released in May with all the fixes, but was delayed so that some obscure new features could be added as well. Why not do two SPs, then? Weird...

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