BIOS preventing access to QPI performance counters

Are you experiencing issues with accessing the performance counters to measure QPI traffic on Intel Xeon processors E5 family? For examples, you might run into the following error message when you try to execute Intel Performance Counter Monitor (Intel PCM) on such a system:

ERROR: QPI LL counter programming seems not to work. Q_P0_PCI_PMON_BOX_CTL=0xffffffff

       Please see BIOS options to enable the export of performance monitoring devices.

The explanation is that the BIOS is hiding this device from you and tools like Intel PCM can therefore not access the required registers. Please check if there is an option available in your BIOS to enable the access. Since there is no special device driver available, Windows users will see a unsupported device as soon as they enable the option.

In case such an option is not available in the BIOS, please verify if a newer BIOS is available. Otherwise, you might need to contact the system vendor and ask for a BIOS with an option to enable access to these registers. The process of enabling the PCI config register access for QPI performance monitoring has recently been documented in in section 7.5.56 of the Intel® Xeon® Processor E5-1600/2400/2600/4600 Product Families and Intel® Xeon® Processor E5-1600/2400/2600/4600 V2 Product Families BIOS Specification Update, rev 1.1.2 (Bios Writers guide). Passing this information on to your system vendor will help the system vendor to service your request.

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4 comments

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John L.'s picture

Hi Thomas, yes that would be great. I can't seem to find your email address on here, mine is jlange trendium.com. Thanks!

Thomas Willhalm (Intel)'s picture

John,
the document is Intel confidential. Can we maybe follow up by email?
Kind regards
Thomas

John L.'s picture

Thomas said:
"The process of enabling the PCI config register access for QPI performance monitoring has recently been documented in in section 7.5.56 of the Intel® Xeon® Processor E5-1600/2400/2600/4600 Product Families and Intel® Xeon® Processor E5-1600/2400/2600/4600 V2 Product Families BIOS Specification Update, rev 1.1.2 (Bios Writers guide)."

I am unable to find these references. I believe I found what appears to be the specified document, but there is no Section 7.5.56, nor any information on enabling the QPI performance monitoring registers. Could someone kindly provide the links to the correct documents?
Thanks in advance!

Zheng Luo's picture

Hello Thomas,

Even though I updated my BIOS, I still get wrong data of the QPI reading.

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