Datasheet
Intel® Xeon® Processor E5-1600/E5-2600/E5-4600 v2 Product Families 61
Datasheet Volume One of Two
Interfaces
status information. Refer to Section 2.5.5.2 for details regarding completion codes.
2.5.2.7.2 Processor ID Enumeration
The ‘Processor ID’ field that is used to address the IA MSR space refers to a specific
logical processor within the CPU. The ‘Processor ID’ always refers to the same physical
location in the processor silicon regardless of configuration as shown in the example in
Figure 2-42. For example, if certain logical processors are disabled by BIOS, the
Processor ID mapping will not change. The total number of Processor IDs on a CPU is
product-specific.
‘Processor ID’ enumeration involves discovering the logical processors enabled within
the CPU package. This can be accomplished by reading the ‘Max Thread ID’ value
through the RdPkgConfig() command (Index 0, Parameter 3) described in
Section 2.5.2.6.12 and subsequently querying each of the supported processor
threads. Unavailable processor threads will return a completion code of 0x90.
Alternatively, this information may be obtained from the RESOLVED_CORES_MASK
register readable through the RdPCIConfigLocal() PECI command described in
Section 2.5.2.9 or other means. Bits [7:0] and [9:8] of this register contain the ‘Core
Mask’ and ‘Thread Mask’ information respectively. The ‘Thread Mask’ applies to all the
enabled cores within the processor package as indicated by the ‘Core Mask’. For
the processor PECI clients, the ‘Processor ID’ may take on values in the range 0
through 23.
Figure 2-42. Processor ID Construction Example
T0T1T0T1T0T1T0T1T0T1T0T1T0T1T0T1
C0C1C2C3…………………C10C11C12
0123456………………181920212223
Processor
ID (0...23)
Cores 0,1,2...12
Thread (0,1) Mask for Core10
7