Supermicro X13DEG-M User Manual page 108

Super X13DEG-M User's Manual
Link L1 Enable
Select Enable for the BIOS to activate Link L1 support which will power down the UPI links
to save power when the system is idle. This feature is available for the system that uses
Intel processors with UPI technology support. The options are Disable, Enable, and Auto.
Note: Link L1 is an excellent feature for an idle system. L1 is used during Package
C-States when its latency is hidden by other components during a wakeup.
KTI Prefetch
Keizer Technology Interconnect (KTI) is also known as the Intel Ultra Path Interconnect
(UPI) technology. Select Enable for the KTI prefetcher to preload the L1 cache with data
deemed relevant, which will allow the memory read to start earlier on a DDR bus in an
effort to reduce latency. Select Auto for the KTI prefetcher to automatically preload the L1
cache with relevant data whenever is needed. The options are Disable, Enable, and Auto.
IO Directory Cache (IODC)
Select Enable for the IODC 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 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. Enable this feature to improve average latency and reduce memory access
congestion for higher performance. The options are Auto, Disable, Enable SNC2 (2-clus-
ters), and Enable SNC4 (4-clusters).
Note: The option of Enable SNC4 (4-clusters) depends on your system configuration
and the processor.
Stale AtoS (A to S)
The in-memory directory has three states: I, A, and S states. The I (-invalid) state indi-
cates 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 and if the directory line is in A state, we must snoop all other sockets because
another socket may have the line in a modified state. If this is the case, a "snoop" will
return the modified data. However, it may be the case that a line "reads" in an A state,
and all the snoops come back with a "miss". This can happen if another socket reads the
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