Datasheet

Intel® Xeon® Processor E5-1600/E5-2600/E5-4600 v2 Product Families 55
Datasheet Volume One of Two
Interfaces
2.5.2.6.22 Thermally Constrained Time Read
This features allows the PECI host to access the total time for which the processor has
been operating in a lowered power state due to TCC activation. The returned data
includes the time required to ramp back up to the original P-state target after TCC
activation expires. This timer does not include TCC activation as a result of an external
assertion of PROCHOT_N. This is tracked by a 32-bit counter with a resolution of 1mS
per count that rolls over or wraps around. On the processor PECI clients, the only logic
that can be thermally constrained is that supplied by VCC.
2.5.2.6.23 Current Limit Read
This read returns the current limit for the processor VCC power plane in 1/8A
increments. Actual current limit data is contained only in the lower 13 bits of the
response data. The default return value of 0x438 corresponds to a current limit value
of 135A.
2.5.2.6.24 Accumulated Energy Status Read
This service can return the value of the total energy consumed by the entire processor
package or just the logic supplied by the VCC power plane as specified through the
parameter field in Table 2-8. This information is tracked by a 32-bit counter that wraps
around and continues counting on reaching its limit. Energy units for this read are
determined as per the Package Power SKU Unit settings described in
Section 2.5.2.6.13.
While Intel requires reading the accumulated energy data at least once every 16
seconds to ensure functional correctness, a more realistic polling rate
recommendation is once every 100mS for better accuracy. This feature assumes a
150W processor. In general, as the power capability decreases, so will the minimum
polling rate requirement.
When determining energy changes by subtracting energy values between successive
reads, Intel advocates using the 2’s complement method to account for counter wrap-
arounds. Alternatively, adding all ‘F’s (‘0xFFFFFFFF’) to a negative result from the
subtraction will accomplish the same goal.
Figure 2-32. Thermal Averaging Constant Write / Read
Thermal Averaging Constant
RESERVED
431
PECI Temperature
Averaging Constant
3 0
Figure 2-33. Current Config Limit Read Data
Current Config Limit Data
RESERVED
1331
Current Limit for processor VCC
12 0