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The Tcontrol portion of the DTS based thermal specification is a one time calculation:
T
control_spec
Tcontrol is defined in
The final DTS based thermal specification is the maximum of both:
T
DTS_max
The margin (M) between the actual die temperature and the DTS based thermal
specification is used in the fan speed control algorithm. When M < 0, increase fan
speed. When M ≥ 0, fan speed may decrease.
M = T
OR
M = T
Tsensor represents the absolute temperature of the processor as power changes:
Tsensor = TEMPERATURE_TARGET [23:16] + DTS
T
DTS_ave
TEMPERATURE_TARGET [23:16], the temperature at which the processor thermal
control circuit activates, is a one time PECI readout: RdPkgConfig(), Temperature
Target Read, 23:16.
DTS, the relative temperature from thermal control circuit activation, is negative by
definition, and changes instantaneously. DTS command info is given in
5.8.4
Power Calculation for the Intel® Xeon® Processor E5-
2400 Product Family
To implement DTS based thermal specification, average power over time must be
calculated:
P = (E2 - E1) / (t2 - t1)
Where:
t1 = time stamp 1
t2 = time stamp 2
E1 = Energy readout at time t1
E2 = Energy readout at time t2
The recommended time interval between energy readings is 1 second. This helps
ensure the power calculation is accurate by making the error between time stamps
small as compared to the duration between time stamps.
For details regarding energy readings, see Platform Digital Thermal Sensor (DTS)
Based Thermal Specifications and Overview.
5.8.5
Averaging the DTS Based Thermal Specification for the
Intel® Xeon® Processor E5-2400 Product Family
Averaging the DTS Based Thermal Specification helps keep the rate of change of the
temperature specification on the same scale as the actual processor temperature, and
helps avoid rapid changes in fan speed when power changes rapidly.
42
= TEMPERATURE_TARGET [23:16] - Tcontrol + Tcontrol_offset
Section
5.6.1.1. Tcontrol_offset is defined in
= max[T
control_spec
- Tsensor
DTS_max
– Tsensor
DTS_ave
is defined in
Section
5.8.5.
, T
]
DTS
Intel® Xeon® Processor E5-2400 Product Family
Thermal Solutions
Section
5.6.1.2.
Section
5.6.1.1.
Thermal/Mechanical Design Guide
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