Uncore Manual

Reference Number: 329468-002 139
Uncore Performance Monitoring
Intel® QPI Link Layer Performance Monitoring
2.8.4 Intel® QPI LL Performance Monitoring Events
2.8.4.1 An Overview
The Intel
®
QPI Link Layer provides events to gather information on topics such as:
• Tracking incoming (ring bound)/outgoing (system bound) transactions,
• Various queue that track those transactions,
• The Link Layer’s power consumption as expressed by the time spent in the Link power states
L0p (half of lanes are disabled).
• A variety of static events such as Direct2Core statistics and when output credit is unavailable.
• Of particular interest, total link utilization may be calculated by capturing and subtracting
transmitted/received idle flits from Intel
®
QPI clocks.
Many of these events can be further broken down by message class, including link utilization.In order
to measure several of the available events in the Intel
®
QPI Link Layer, an extra bit (b16) must be set.
These cases will be documented in the full Event List.
2.8.5 QPI LL Box Events Ordered By Code
The following table summarizes the directly measured QPI LL Box events.
qpi_rate 2:0 RO-V 11b QPI Rate
This reflects the current QPI rate setting into the PLL
010 - 5.6 GT/s
011 - 6.4 GT/s
100 - 7.2 GT/s
101 - 8 GT/s
110 - 8.8 GT/s
111 - 9.6 GT/s
other - Reserved
Symbol Name
Event
Code
Ctrs
Extra
Select
Bit
Max
Inc/
Cyc
Description
TxL_FLITS_G0 0x00 0-3 0 2 Flits Transferred - Group 0
RxL_FLITS_G0 0x01 0-3 0 2 Flits Received - Group 0
TxL_INSERTS 0x04 0-3 0 1 Tx Flit Buffer Allocations
TxL_BYPASSED 0x05 0-3 0 1 Tx Flit Buffer Bypassed
TxL_CYCLES_NE 0x06 0-3 0 1 Tx Flit Buffer Cycles not Empty
TxL_OCCUPANCY 0x07 0-3 0 1 Tx Flit Buffer Occupancy
RxL_INSERTS 0x08 0-3 0 1 Rx Flit Buffer Allocations
RxL_BYPASSED 0x09 0-3 0 1 Rx Flit Buffer Bypassed
RxL_CYCLES_NE 0x0a 0-3 0 1 RxQ Cycles Not Empty
RxL_OCCUPANCY 0x0b 0-3 0 128 RxQ Occupancy - All Packets
TxL0_POWER_CYCLES 0x0c 0-3 0 1 Cycles in L0
TxL0P_POWER_CYCLES 0x0d 0-3 0 1 Cycles in L0p
Field Bits Attr
HW
Reset
Val
Description