Reference Number: 327043-001
129
Intel® Xeon® Processor E5-2600 Product Family Uncore Performance Monitoring
VN0_CREDITS_USED
• Title:
VN0 Credit Used
• Category:
LINK_VN0_CREDITS Events
• Event Code:
0x36
• Max. Inc/Cyc:
1,
Register Restrictions:
0-1
• Definition:
Number of times a VN0 credit was used on the DRS message channel. In order for a
request to be transferred across Intel® QPI, it must be guaranteed to have a flit buffer on the
remote socket to sink into. There are two credit pools, VNA and VN0. VNA is a shared pool used to
achieve high performance. The VN0 pool has reserved entries for each message class and is used
to prevent deadlock. Requests first attempt to acquire a VNA credit, and then fall back to VN0 if
they fail. This counts the number of times a VN0 credit was used. Note that a single VN0 credit
holds access to potentially multiple flit buffers. For example, a transfer that uses VNA could use 9
flit buffers and in that case uses 9 credits. A transfer on VN0 will only count a single credit even
though it may use multiple buffers.
NDR
bxxxxx1xx
NDR Message Class:
NDR packets are used to transmit a variety of protocol flits including
grants and completions (CMP).
DRS
bxxxx1xxx
DRS Message Class:
Filter for Data Response (DRS). DRS is generally used to transmit
data with coherency. For example, remote reads and writes, or
cache to cache transfers will transmit their data using DRS.
NCB
bxxx1xxxx
NCB Message Class:
Filter for Non-Coherent Broadcast (NCB). NCB is generally used to
transmit data without coherency. For example, non-coherent read
data returns.
NCS
bxx1xxxxx
NCS Message Class:
Filter for Non-Coherent Standard (NCS). NCS is commonly used for
Ö
Table 2-140. Unit Masks for VN0_CREDITS_USED
Extension
umask
[15:8]
Description
HOM
bxxxxxxx1
HOM Message Class:
Filter for the Home (HOM) message class. HOM is generally used to
send requests, request responses, and snoop responses.
SNP
bxxxxxx1x
SNP Message Class:
Filter for Snoop (SNP) message class. SNP is used for outgoing
snoops. Note that snoop responses flow on the HOM message class.
NDR
bxxxxx1xx
NDR Message Class:
NDR packets are used to transmit a variety of protocol flits including
grants and completions (CMP).
DRS
bxxxx1xxx
DRS Message Class:
Filter for Data Response (DRS). DRS is generally used to transmit
data with coherency. For example, remote reads and writes, or
cache to cache transfers will transmit their data using DRS.
NCB
bxxx1xxxx
NCB Message Class:
Filter for Non-Coherent Broadcast (NCB). NCB is generally used to
transmit data without coherency. For example, non-coherent read
data returns.
NCS
bxx1xxxxx
NCS Message Class:
Filter for Non-Coherent Standard (NCS). NCS is commonly used for
Ö
Table 2-139. Unit Masks for VN0_CREDITS_REJECT (Sheet 2 of 2)
Extension
umask
[15:8]
Description