I
NTEL
® X
EON
® P
ROCESSOR
7500 S
ERIES
U
NCORE
P
ROGRAMMING
G
UIDE
UNCORE PERFORMANCE MONITORING
2-51
Table 2-35. S_MSR_MASK Register – Field Definitions
2.5.4
S-BOX Performance Monitoring Events
2.5.4.1
An Overview
The S-Box provides events to track incoming (ring bound)/outgoing (system bound) transactions,
various queue occupancies/latencies that track those transactions and a variety of static events such as
bypass use (i.e. EGRESS_BYPASS) and when output credit is unavailable (i.e. NO_CREDIT_SNP). Many
of these events can be further broken down by message class.
2.5.4.2
On Queue Occupancy Usage
This means two things:
a) none of the physical queues receive more than one entry per cycle
b) The entire 7b from the ‘selected’ (by the event select) queue occ subcounter is sent to the generic
counter each cycle, meaning that the max inc of a generic counter is 64 (for the sys bound HOM
buffer).
Associated with each of the four general purpose counters is a 7b queue occupancy counter which
supports the various queue occupancy events found in
Section 2.5.5, “S-Box Events Ordered By Code”
Each System Bound and Ring Bound data storage structure within the S-Box (queue/FIFO/buffer) has
an associated tally counter which can be used to provide input into one of the S-Box performance
counters. The data structure the tally counter is ‘attached’ to then sends increment/decrement signals
as it receives/removes new entries. The tally counter then sends its contents to the performance
counter each cycle.
The following table summarizes the queues (and their associated events) responsible for buffering
traffic into and out of the S-Box.
Field
Bits
HW
Reset
Val
Description
ig
62:39
Read zero; writes ignored.
addr
38:1
0 Mask PA address bits [43:6].
For each mask bit that is set, the corresponding bit in the address is
already considered matched (e.g. it is ignored). If it is clear the it must
match the corresponding address match bit in the S_MSR_MATCH
register.
hnid
0
0 Disable HNID matching.
1 - HNID is NOT matched
0 - HNID is compared against the match