Chapter 4: UEFI BIOS
81
Degrade Precedence
Use this feature to select the degrading precedence option for Ultra Path Interconnect (UPI)
connections. Select Topology Precedent to degrade UPI features if system options are in
conflict. Select Feature Precedent to degrade UPI topology if system options are in conflict.
The options are
Topology Precedence
and Feature Precedence.
Link L0p Enable
Select Enable to enable Link L0p. The options are Disable, Enable, and
Auto
.
Link L1 Enable
Select Enable to enable Link L1 (Level 1 link). The options are Disable, Enable, and
Auto
.
IO Directory Cache (IODC)
Select Enable for the
IODC (I/O Directory Cache) to generate snoops instead of generating memory lockups for
remote IIO (InvIToM) and/or WCiLF (Cores). Select Auto for the IODC to generate snoops
(instead of memory lockups) for WCiLF (Cores). The options are Disable,
Auto
, Enable
for Remote InvItoM Hybrid Push, InvItoM AllocFlow, Enable for Remote InvItoM Hybrid
AllocNonAlloc, and Enable for Remote InvItoM and Remote WCiLF.
SNC
Select Enable to use "Sub NUMA Clustering" (SNC), which supports full SNC (2-cluster)
interleave and 1-way IMC interleave. Select Auto for 1-cluster or 2-cluster support depending
on the status of IMC (Integrated Memory Controller) Interleaving. The options are
Disable
,
Enable, and Auto.
XPT Prefetch
Select Enable to support XPT Prefetching to enhance system performance. The options
are Enable,
Disable
, and Auto.
KTI Prefetch
Select Enable to support KTI Prefetching to enhance system performance. The options
are
Enable
and Disable.
Local/Remote Threshold
This feature allows the user to set the threshold for the Interrupt Request (IRQ) signal, which
handles hardware interruptions. The options are Disable,
Auto
, Low, Medium,
and High.
Stale AtoS (A to S)
The in-memory directory has three states: I, A, and S states. The I (-invalid) state indicates
that the data is clean and does not exist in the cache of any other sockets. The A (-snoop
All) state indicates that the data may exist in another socket in an exclusive or modified
state. The S state (-Shared) indicates that the data is clean and may be shared in the
caches across one or more sockets. When the system is performing "read" on the memory
