2 Replies Latest reply: Jun 2, 2011 10:22 AM by generalking RSS

5520 chipset (rev 13) vt-d snoop issue

generalking Community Member
Currently Being Moderated

Hi,

 

I am doing a vga passthru test on a HP Z800 workstation which has:

Intel 5520 chipset (rev 13)

Xeon X5680 CPU

32G memory

nvidia quadro fx5800 gfx card

SUSE11.4(xen4.0.2)

win2003 x64 guest

 

, but after passthru the vga card to vm, the vm run very slow, the cpu ut is very high for any operation in guest. some clues from my investigation:

 

1. guest reponse speed has relationship with the virtual memory assigned to it, e.g, a 4G VM is faster than a 8G VM.

2. another machine with Intel 5500(rev 22) has no this problem.

3. check xen dmesg, the snoop control was not enable, but the 5500(rev 22) machine has snoop control enabled.

 

From the document at http://www.intel.com/Assets/PDF/specupdate/321329.pdf, there is a defect: "Bandwith very slow for write traffic with noSnoop attribute set", does my problem relate to the defect? if yes, how to resolve it?

 

It seems the revision 22 fixed it?

 

 

Thank you,

Jin Cui

  • 1. Re: 5520 chipset (rev 13) vt-d snoop issue
    Salem_Intel Community Member
    Currently Being Moderated

    Hi,

    The situation you describe may very well match that stated on Errata # 24 on the Specification Update document you referred to, and thus, as a recommendation, I'd suggest making sure the BIOS is updated, and if you've already done this, then, please, contact either your place of purchase or HP for board-wise troubleshooting and/or advice.

  • 2. Re: 5520 chipset (rev 13) vt-d snoop issue
    generalking Community Member
    Currently Being Moderated

    Yesterday, I updated BIOS to the last version, but the problem still there.

    I also had try the workaround of Errordata #24 (set the PERFCTRLSTS register bit 3 and 2 set to 0), it doesn't help. Actually, they are already set to 0 by default.

    Any information about changes from rev 13(B3) to rev 22(C2)? add snoop control feature? Thanks you very much!

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