Uncore Manual

Uncore Performance Monitoring
Packet Matching Reference
190 Reference Number: 329468-002
be transmitted, as those holding VN0 credits will still (potentially) be able to transmit. Generally it is
the goal of the uncore that VNA credits should not run out, as this can substantially throttle back
useful QPI bandwidth.
VNA_CREDIT_CYCLES_USED
• Title: Cycles with 1 or more VNA credits in use
• Category: LINK_VNA_CREDITS Events
• Event Code: 0x32
• Max. Inc/Cyc:. 1, Register Restrictions: 0-1
• Definition: Number of QPI uclk cycles with one or more VNA credits in use. This event can be used
in conjunction with the VNA In-Use Accumulator to calculate the average number of used VNA cred-
its.
2.11 PACKET MATCHING REFERENCE
In the Intel
®
QPI Link Layer, the performance monitoring infrastructure allows a user to filter packet
traffic according to certain fields. A couple common fields, the Message Class/Opcode fields, have been
summarized in the following tables.
Table 2-216. Intel® QuickPath Interconnect Packet Message Classes
Table 2-217. Opcode Match by Message Class
Code Name Definition
b0000 HOM0 Home - Requests
b0001 HOM1 Home - Responses
b0010 NDR Non-Data Responses
b0011 SNP Snoops
b0100 NCS Non-Coherent Standard
---
b1100 NCB Non-Coherent Bypass
---
b1110 DRS Data Response
Opc HOM0 HOM1 NDR SNP
0000 RdCur RspI Gnt_Cmp SnpCur
0001 RdCode RspS GntE_FrcAckCnflt SnpCode
0010 RdData --- --- SnpData
0011 NonSnpRd --- --- ---
0100 RdInvOwn RspCnflt CmpD SnpInvOwn
0101 --- SnpInvWrMtoI
(aka SnpInvXtoI)
0110 EvctCln
(only to xNCs)
--- ---
0111 NonSnpWr RspCnfltWbI
(only from xNCs)
--- ---
1000 InvItoE RspFwd Cmp SnpInvItoE