vmotion between SSE2, 3 & 4

[hp_Bladefanatic]

Hi Guys!

Interesting Topic: Since woodcrest vs dempsey has add new SSE Instructions WC SSE4 D SSE3 they are not vmotion compatible. Ok, so far as well, not every OS/APP uses this Instructions, it is possible to have sucessful migration, you go within VI3 into VM Properties-->Options -->Advanced and mark "Hide the nx flag from guest"

My question: Have you ever done something like that between SSE2 & SSE3 or SSE2 & SSE4? I really want to know where is the limit and what is your experience?

thanx

[mstahl75]

VC, in the process of doing cold migrates with a server containing dual-core CPUs creates CPU masks for the VMs. The other servers in the farm are single-core and from what I can tell the dual-core have SSE4 instruction causing the masking to occur. I won't know for positive until we get our last server on 3.0 and attempt to VMotion one server that was created on ESX 3.0 and not migrated.

[Andreas_Besser]

Hi Bladefanatic,

i actually have the problem that i cannot "vmotion" VMs from a HP DL380 3.4 GHz (SSE3) to a FSC TX300 3.0 GHz (SSE2).

Both are ESX3 servers integrated in VC2. There is always the error-message that the cpu's are incompatible on CPUID Level 0x1 register ecx. Today I have opened a ticket at VMware-support and hope they got a resolution for the problem...

Regards

Andreas

[hp_Bladefanatic]

Andreas,

have you tried to mark "Hide the nx flag from guest" in vm properties?

Michi

[Andreas_Besser]

Hi Michi,

yes i had set the flag.

In the meantime i have the answer from the support-guys:

==========================================

Hello Andreas,

Thank you for your Support Request.

I'm afraid there is no way to reconfigure your system so these processors are

compatible with Vmotion. The reason is that they are different family

processors with very different characteristics.

Please review KB article from following links for more information.

http://kb.vmware.com/kb/1991

Please let me know if you have any more questions.

======================================

So i have to look for another server-hardware.

Andreas

[mstahl75]

If you actually had the processors in question in production and in the same VC farm then I would suggest doing a cold migrate across LUNs if at all possible with a test server.

When I did this in my upgrade from 2.5.x to 3.0 CPU masks were automatically created due to the differences in between my hosts. It might be possible that VC will see that and mask off the appropriate registers.

[frozenchicken]

I have the same issue... I have 2 Dell PowerEdge 2850's, their SSE3... I just got a screaming 2950 w/ Woodcrest procs that are SSE4 and my VM's will not VMotion to it. It passes validation if it's turned off and migrated (I haven't actually moved any VM's to it yet). Can't I set CPU Identification Masks on my VM's to just not use SSE4? All are ESX 3.0, and VC 2.0.

Another issue I'm seeing is that my Dell 2950 Woodcrest says it's Hyperthreading capable when I run cpuID, and in VC it's "Enabled(Not Active)" and says I need to enable it in the BIOS, but I see no settings in the BIOS for enabling Hyperthreading... hmmm... well at least there is that 1.3Ghz Proc Bus..! woo!

[frozenchicken]

Looking more into this, The Intel datasheet says NOTHING about Woodcrest (5160) having SSE4 support, AND the Intel documentation says there is NO Hyperthreading in this chip!

ftp://download.intel.com/design/Xeon/datashts/31335501.pdf

cpuID although, says it's got SSE4 and Hyperthreading! It's interesting because I'd like to figure out what bits to mask so it doesn't think it has SSE4... which is what I think is making VMotion fail... Another interesting tidbit is that VC thinks the chip too supports Hyperthreading and suggests that I go into the BIOS and enable it... there is NO Hyperthreading on this chip!

Anyone have any ideas on a good CPU mask for The Intel Woodcrest 5160?

I tried masking a few bits that may be related with not much luck... there is no documentation I can find that is telling me what bits are telling cpuID that SSE4 is supported.

[neelagiri]

hey did u solve your dell 2950, in VC its "Enabled(Not active). just installed today i got same problem if u have any soluation plzzzzzzzzzzzzz..

[frozenchicken]

so! I figured out how to decipher the CPU mask to fool VC into thinking VMotion is okay but I am worried about a couple of bits...

these are my cpuinfo's

Host: esx01

/proc/vmware/cpuinfo

pcpu 00 01 02 03

family 15 15 15 15

model 04 04 04 04

type 00 00 00 00

stepping 01 01 01 01

cpuKhz 3591000 3591000 3591000 3591000

busKhz 199500 199500 199500 199500

name GenuineIntel GenuineIntel GenuineIntel GenuineIntel

ebx 0x00020800 0x01020800 0x06020800 0x07020800

ecxFeat 0x0000659d 0x0000659d 0x0000659d 0x0000659d

edxFeat 0xbfebfbff 0xbfebfbff 0xbfebfbff 0xbfebfbff

initApic 0x00000000 0x00000001 0x00000006 0x00000007

apicID 0x00000000 0x00000001 0x00000006 0x00000007

Host: esx03

/proc/vmware/cpuinfo

pcpu 00 01 02 03

family 06 06 06 06

model 15 15 15 15

type 00 00 00 00

stepping 06 06 06 06

cpuKhz 2992500 2992500 2992500 2992500

busKhz 332500 332500 332500 332500

name GenuineIntel GenuineIntel GenuineIntel GenuineIntel

ebx 0x00020800 0x01020800 0x06020800 0x07020800

ecxFeat 0x0004e3bd 0x0004e3bd 0x0004e3bd 0x0004e3bd

edxFeat 0xbfebfbff 0xbfebfbff 0xbfebfbff 0xbfebfbff

initApic 0x00000000 0x00000001 0x00000006 0x00000007

apicID 0x00000000 0x00000001 0x00000006 0x00000007

I took the HEX of the ecxFeat and converted it to BIN:

0000 0000 0000 0000 0110 0101 1001 1101 esx01

0000 0000 0000 0100 1110 0011 1011 1101 esx03

you can see bits 5, 9, 10, 15 and 18 are different... If I mask them in VC on the VM like this:

Edit Settings > Options tab > Advanced > Advanced Button

Level 1

ecx -

---

-

---

-

---

-0-- 0-0- --0- -R0- -

---

0 means hide feature from VM and the R is hide it, but it is required for VMotion... bit 6 was identical so I just left it...

Then the VM passes validation for VMotion... (I haven't done it yet tho- I'm worried about bits 9 and 10... as you can see they are opposite... all the others I feel comfortable just not letting the VM know that those features are available, but 9 and 10 are a different story... according to the Intel Feature Flags cpuID document bit 9 is the "On-chip APIC Hardware Supported" flag and 10 is a "reserved" flag... so I'm kindof at a loss as to what the implications of masking those bits are... doesn't seem like it should be that big a deal but I'd like to find out...

any ideas if this might work? or, more importantly be stable? I'm going to try it on a throw away VM...

[frozenchicken]

>>hey did u solve your dell 2950, in VC its "Enabled(Not active). just >>installed today i got same problem if u have any soluation >>plzzzzzzzzzzzzz..

If your talking about the Hyperthreading...

The Intel Woodcrest 5160 DOES NOT have Hyperthreading! When you run the cpuid.iso it says Yes! but the Intel documentation says it does not have Hyperthreading... check out this chart...

http://www.intel.com/products/processor_number/chart/xeon.htm

I think it's probaly a problem with the 2950 BIOS...

[neelagiri]

thanks body

[AnthonyCCU]

Have you tried enabling this in the CPU section of the BIOS?

Virtualization Technology

(Disabled default)

Displays when the processor(s) support Virtualization Technology. Enabled permits virtualization software to utilize Virtualization Technology functions

[mindli]

hi all

What about the BIOS setting 'Virtualization Technology'. What does this function do in detail, what benefits will i get when enabling it?

cheers

mindli

Message was edited by:

mindli

[VMWELC]

frozenchicken!! I noticed it's been about 1 year since you've tried out the PE2850 and PE2950 vmotion configuration.

Are the 2 in production now? I ask because we're thinking about buying the PE2950 and don't know what will make vmotion in the end with our existing PE2850 --

1. change the masks to disable SSE4 on PE2950?

2. or do a cold migration of the VM to PE2950?

Thanks

PS Sorry if say something wrong ...it's my first post here on vmtn forums