Check and configure Cache Allocation Technology (“CAT”) (cattool.exe)

This utility confirms or sets a configuration for Cache Allocation Technology (“CAT”) on the local platform. A good CAT configuration can reduce jitter caused by last-level cache pollution. Cache pollution can come from Windows processors or even the graphics controller on some processor architectures.

Command line

cattool [ query | off | on | save | print | help ]

Available options

With no parameters, the utility displays the current configuration

query	show current configuration
off	disable CAT configuration
on	enable a default CAT configuration
save	save the enabled configuration to registry
print	print registry configuration
help	display this text

Notes

Cache Allocation Technology (“CAT”) may be used to reduce jitter caused by cache pollution in the last-level cache (“LLC”) on many CPUs. This cache is usually shared by all cores in a processor and sometime also the graphics controller so that activity by Windows and the graphics controller may cause non-deterministic behavior when INtime reads data which might be expected to be cached.

The general operation of CAT divides the LLC into a number of sections called “ways” which may be allocated to one or more processing elements by means of a bit mask.

TBD

The default configuration allocates half of the last-level cache to Windows and the other half to INtime. COS 1 defines the Windows mask, and COS 2 is used to define the INtime mask. If both Level 2 and Level 3 CAT is enabled, then both levels will be similarly apportioned. The tool detect and attempts to configure both Architectural and Non-Architectural implementations (Intel CPUs). Note that in some cases non-Architectural implementations may be detected but are non-functional (some Intel CPUs).