Uncore Manual

Reference Number: 329468-002 189
Uncore Performance Monitoring
R3QPI Performance Monitoring
VNA_CREDITS_REJECT
• Title: VNA Credit Reject
• Category: LINK_VNA_CREDITS Events
• Event Code: 0x34
• Max. Inc/Cyc:. 1, Register Restrictions: 0-1
• Definition: Number of attempted VNA credit acquisitions that were rejected because the VNA
credit pool was full (or almost full). It is possible to filter this event by message class. Some pack-
ets use more than one flit buffer, and therefore must acquire multiple credits. Therefore, one
could get a reject even if the VNA credits were not fully used up. The VNA pool is generally used to
provide the bulk of the QPI bandwidth (as opposed to the VN0 pool which is used to guarantee
forward progress). VNA credits can run out if the flit buffer on the receiving side starts to queue
up substantially. This can happen if the rest of the uncore is unable to drain the requests fast
enough.
VNA_CREDIT_CYCLES_OUT
• Title: Cycles with no VNA credits available
• Category: LINK_VNA_CREDITS Events
• Event Code: 0x31
• Max. Inc/Cyc:. 1, Register Restrictions: 0-1
• Definition: Number of QPI uclk cycles when the transmitted has no VNA credits available and
therefore cannot send any requests on this channel. Note that this does not mean that no flits can
Table 2-214. Unit Masks for VNA_CREDITS_ACQUIRED
Extension
umask
[15:8]
Description
AD bxxxxxxx1 HOM Message Class
Filter for the Home (HOM) message class. HOM is generally used
to send requests, request responses, and snoop responses.
BL bxxxxx1xx HOM Message Class
Filter for the Home (HOM) message class. HOM is generally used
to send requests, request responses, and snoop responses.
Table 2-215. Unit Masks for VNA_CREDITS_REJECT
Extension
umask
[15:8]
Description
HOM bxxxxxxx1 HOM Message Class
Filter for the Home (HOM) message class. HOM is generally used
to send requests, request responses, and snoop responses.
SNP bxxxxxx1x SNP Message Class
Filter for Snoop (SNP) message class. SNP is used for outgoing
snoops. Note that snoop responses flow on the HOM message
class.
NDR bxxxxx1xx NDR Message Class
NDR packets are used to transmit a variety of protocol flits
including grants and completions (CMP).
DRS bxxxx1xxx DRS Message Class
Filter for Data Response (DRS). DRS is generally used to
transmit data with coherency. For example, remote reads and
writes, or cache to cache transfers will transmit their data using
DRS.
NCB bxxx1xxxx NCB Message Class
Filter for Non-Coherent Broadcast (NCB). NCB is generally used
to transmit data without coherency. For example, non-coherent
read data returns.
NCS bxx1xxxxx NCS Message Class
Filter for Non-Coherent Standard (NCS).