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Intel® Xeon® Processor E5-1600 v2/E5-2600 v2 Product Families 57
Datasheet Volume One of Two
Interfaces
2.5.2.6.27 Package Power Limit Performance Status Read
This service allows the PECI host to assess the performance impact of the currently
active power limiting modes. The read return data contains the total amount of time for
which the entire processor package has been operating in a power state that is lower
than what the operating system originally requested. This information is tracked by a
32-bit counter that wraps around. The unit for time is determined as per the Package
Power SKU Unit settings described in w are determined as per the Package Power SKU
Unit settings described in Section 2.5.2.6.13.
2.5.2.6.28 Efficient Performance Indicator Read
The Efficient Performance Indicator (EPI) Read provides an indication of the total
number of productive cycles. Specifically, these are the cycles when the processor is
engaged in any activity to retire instructions and as a result, consuming energy. Any
power management entity monitoring this indicator should sample it at least once
every 4 seconds to enable detection of wraparounds. Refer to the Intel® 64 and IA-32
Architectures Software Developer’s Manual, for details on programming the
IA32_ENERGY_PERFORMANCE_BIAS register to set the ‘Energy Efficiency’ policy of
the processor.
Figure 2-36. Package Turbo Power Limit Data
Package Power Limit 1
Power Limit
Enable #1
1523
Power Limit # 1
14 0
Clamp
Mode #1
16
Control Time
Window #1
1731
RESERVED
24
Package Power Limit 2
Power Limit
Enable #2
4755
Power Limit # 2
46 32
Clamp
Mode #2
48
Control Time
Window #2
4963
RESERVED
56
Figure 2-37. Package Power Limit Performance Data
Accumulated CPU Throttle Time
Accumulated CPU Throttle Time
0
31