Uncore Manual

Uncore Performance Monitoring
Intel® QPI Link Layer Performance Monitoring
152 Reference Number: 329468-002
• Definition: Number of allocations into the QPI Rx Flit Buffer. Generally, when data is transmitted
across QPI, it will bypass the RxQ and pass directly to the ring interface. If things back up getting
transmitted onto the ring, however, it may need to allocate into this buffer, thus increasing the
latency. This event can be used in conjunction with the Flit Buffer Occupancy event in order to cal-
culate the average flit buffer lifetime. This monitors only SNP flits.
RxL_OCCUPANCY
• Title: RxQ Occupancy - All Packets
• Category: RXQ Events
• Event Code: 0x0b
• Max. Inc/Cyc:. 128, Register Restrictions: 0-3
• Definition: Accumulates the number of elements in the QPI RxQ in each cycle. Generally, when
data is transmitted across QPI, it will bypass the RxQ and pass directly to the ring interface. If
things back up getting transmitted onto the ring, however, it may need to allocate into this buffer,
thus increasing the latency. This event can be used in conjunction with the Flit Buffer Not Empty
event to calculate average occupancy, or with the Flit Buffer Allocations event to track average life-
time.
RxL_OCCUPANCY_DRS
• Title: RxQ Occupancy - DRS
• Category: RXQ Events
• Event Code: 0x15
• Extra Select Bit: Y
• Max. Inc/Cyc:. 128, Register Restrictions: 0-3
• Definition: Accumulates the number of elements in the QPI RxQ in each cycle. Generally, when
data is transmitted across QPI, it will bypass the RxQ and pass directly to the ring interface. If
things back up getting transmitted onto the ring, however, it may need to allocate into this buffer,
thus increasing the latency. This event can be used in conjunction with the Flit Buffer Not Empty
event to calculate average occupancy, or with the Flit Buffer Allocations event to track average life-
time. This monitors DRS flits only.
RxL_OCCUPANCY_HOM
• Title: RxQ Occupancy - HOM
• Category: RXQ Events
• Event Code: 0x18
• Extra Select Bit: Y
• Max. Inc/Cyc:. 128, Register Restrictions: 0-3
• Definition: Accumulates the number of elements in the QPI RxQ in each cycle. Generally, when
data is transmitted across QPI, it will bypass the RxQ and pass directly to the ring interface. If
things back up getting transmitted onto the ring, however, it may need to allocate into this buffer,
thus increasing the latency. This event can be used in conjunction with the Flit Buffer Not Empty
Table 2-150. Unit Masks for RxL_INSERTS_SNP
Extension
umask
[15:8]
Description
VN0 bxxxxxxx1 for VN0
VN1 bxxxxxx1x for VN1
Table 2-151. Unit Masks for RxL_OCCUPANCY_DRS
Extension
umask
[15:8]
Description
VN0 bxxxxxxx1 for VN0
VN1 bxxxxxx1x for VN1