SPEC CPU2006 Platform Settings for Intel-based systems

Firmware / BIOS / Microcode Settings

Hardware Prefetcher:

This BIOS option allows the enabling/disabling of a processor mechanism to prefetch data into the cache according to a pattern-recognition algorithm. This default setting is "Enabled".

In some cases, setting this option to Disabled may improve performance. Users should only disable this option after performing application benchmarking to verify improved performance in their environment.

Adjacent Cache Line Prefetch:

This BIOS option allows the enabling/disabling of a processor mechanism to fetch the adjacent cache line within a 128-byte sector that contains the data needed due to a cache line miss. This default setting is "Enabled".

In some cases, setting this option to Disabled may improve performance. Users should only disable this option after performing application benchmarking to verify improved performance in their environment.

Hyper-Threading:

Disabling Intel's Hyper-Threading Technology reduces the number of threads per core to 1. The default is Enabled; in this case each core provides additional resources for executing up to 2 threads in parallel.

Power Management Policy:

This option selects the power managment policy. If this option is set to "Custom", the processor power management options are selectable independently.

Energy Performance:

This item is displayed when the EIST item is set to "Enabled". This option can only be selectable when the Power Management Policy is set to "Custom". This item decides the energy efficiency policy which is the energy per performance rate. If the highest performance is preferred, this option should be set to "Performance".

Patrol Scrub:

Patrol Scrub is a mechanism for memory controller to periodically read all memory. Corrected read data is written back to memory when a correctable error is detected. This default setting is "Enabled".

Demand Scrub:

Demand Scrub is a mechanism for memory controller to correct a correctable error in memory. Corrected read data is sent to the requestor and written back to memory. This default setting is "Enabled".

Cluster on Die:

Enable/Disable Cluster on Die mode. If this option is set to "Enabled", the Early Snoop is set to "Disabled" automatically by BIOS. This default setting is "Disabled".

Cluster on Die mode logically splits a socket into 2 NUMA domains that are exposed to the OS with half the amount of cores and LLC assigned to each NUMA domain in a socket. This mode utilizes an on-die directory cache and in memory directory bits to determine whether a snoop needs to be sent. Use this mode for highly NUMA optimized workloads to get the lowest local memory latency and highest local memory bandwidth for NUMA workloads.

Early Snoop:

Enable/Disable Early Snoop mode. This option can only be selectable when the Cluster on Die is set to "Disabled". This default setting is "Enabled".

Use Early Snoop mode for workloads that are memory latency sensitive or for workloads that benefit from fast cache-to-cache transfer latencies from the remote socket. Snoops are sent out earlier, which is why memory latency is lower in this mode.