I
NTEL
® X
EON
® P
ROCESSOR
7500 S
ERIES
U
NCORE
P
ROGRAMMING
G
UIDE
UNCORE PERFORMANCE MONITORING
2-33
Table 2-22. B_MSR_MATCH_REG Register – Field Definitions
Table 2-23. B_MSR_MASK_REG Register – Field Definitions
2.4.4
B-Box Performance Monitoring Events
B-box PMUs allow users to monitor a number of latency related events. Traditionally, latency related
events have been calculated by measuring the number of live transactions per cycle and accumulating
this value in one of the PMU counters. The B-box offers a different approach. A number of occupancy
counters are dedicated to track live entries in different queues and structures. Rather than directly
accumulate the occupancy values in the PMU counters, they are fed to a number of accumulators.
Overflow of these accumulator values are then fed into the main PMU counters.
2.4.4.1
On the ARBQ:
The ARBQ (arbitration queue), used to store requests that are waiting for completion or arbitrating for
resources, logically houses several smaller queues.
• COHQ0/1 (Coherence Queues) 256-entry - read request is pushed onto COHQ when it is in the
‘ready’ state (e.g. a read request that has received all of its snoop responses and is waiting for the
M-Box ACK). All snoop responses received or RspFwd* or RspWb* will result in pushing that
transaction onto the COHQ.
• NDROQ (NDR Output Queue) 256-entry - request is pushed when an NDR message has to be sent
but is blocked due to lack of credits or the output port is busy.
Field
Bits
HW
Reset
Val
Description
opc_out
59:56
0 Match to this outgoing opcode
opc_in
55:52
0 Match to this incoming opcode
msg_out
51:48
0 Match to this outgoing message class
MC
12:9
0x0 Message Class
b0000 HOM - Requests
b0001 HOM - Responses
b0010 NDR
b0011 SNP
b0100 NCS
---
b1100 NCB
---
b1110 DRS
msg_in
47:44
0 Match to this incoming message class
addr
43:0
0 Match to this System Address - cache aligned address 49:6
Field
Bits
HW
Reset
Val
Description
opc_out
59:56
0 Mask for outgoing opcode
opc_in
55:52
0 Mask for incoming opcode
msg_out
51:48
0 Mask for outgoing message class
msg_in
47:44
0 Mask for incoming message class
addr
43:0
0 Mask this System Address - cache aligned address 49:6