Chapter 6: BIOS
85
Link L1 Enable
Select Enable for the QPI to enter the L1 state for power saving. The options are Dis-
able, Enable, and
Auto
.
IO Directory Cache (IODC)
Use this feature to enable the IO Directory Cache (IODC) support. The options are Dis-
able, Auto, Enable for Remote InvItoM Hybrid Push, InvItoM AllocFlow, Enable for Remote
InvItoM Hybrid AllocNonAlloc, and Enable for Remote InvItoM and Remote WViLF.
SNC
Sub NUMA Clustering (SNC) is a feature that breaks up the Last Level Cache (LLC) into
clusters based on address range. Each cluster is connected to a subset of the memory
controller. Enabling SNC improves average latency and reduces memory access conges-
tion to achieve higher performance. Select Auto for 1-cluster or 2-clusters depending on
IMC interleave. Select Enable for Full SNC (2-clusters and 1-way IMC interleave). The
options are Disable, Enable, and Auto.
XPT Prefetch
XPT Prefetch is a feature that speculatively makes a copy to the memory controller of
a read request being sent to the LLC. If the read request maps to the local memory ad-
dress and the recent memory reads are likely to miss the LLC, a speculative read is sent
to the local memory controller. The options are
Disable
and Enable.
KTI Prefetch
KTI Prefetch is a feature that enables memory read to start early on a DDR bus, where
the KTI Rx path will directly create a Memory Speculative Read command to the memory
controller. The options are Disable and
Enable
.
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
This feature optimizes A to S directory. When all snoop responses found in directory A
are found to be Rspl, then all data is moved to directory S and is returned in S-state.
The options are
Disable
, Enable, and Auto.