Vol. 3B 14-29
POWER AND THERMAL MANAGEMENT
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Package Thermal Status Log (bit 1, R/WC0) — This is a sticky bit that indicates the history of the thermal
sensor high temperature output signal (PROCHOT#) of the package. Bit 1 = 1 if package PROCHOT# has been
asserted since a previous RESET or the last time software cleared the bit. Software may clear this bit by writing
a zero.
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Package PROCHOT# Event (bit 2, RO) — Indicates whether package PROCHOT# is being asserted by
another agent on the platform.
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Package PROCHOT# Log (bit 3, R/WC0) — Sticky bit that indicates whether package PROCHOT# has been
asserted by another agent on the platform since the last clearing of this bit or a reset. If bit 3 = 1, package
PROCHOT# has been externally asserted. Software may clear this bit by writing a zero.
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Package Critical Temperature Status (bit 4, RO) — Indicates whether the package critical temperature
detector output signal is currently active. If bit 4 = 1, the package critical temperature detector output signal
is currently active.
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Package Critical Temperature Log (bit 5, R/WC0) — Sticky bit that indicates whether the package critical
temperature detector output signal has been asserted since the last clearing of this bit or reset. If bit 5 = 1, the
output signal has been asserted. Software may clear this bit by writing a zero.
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Package Thermal Threshold #1 Status (bit 6, RO) — Indicates whether the actual package temperature is
currently higher than or equal to the value set in Package Thermal Threshold #1. If bit 6 = 0, the actual
temperature is lower. If bit 6 = 1, the actual temperature is greater than or equal to PTT#1. Quantitative
information of actual package temperature can be inferred from Package Digital Readout, bits 22:16.
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Package Thermal Threshold #1 Log (bit 7, R/WC0) — Sticky bit that indicates whether the Package
Thermal Threshold #1 has been reached since the last clearing of this bit or a reset. If bit 7 = 1, the Package
Threshold #1 has been reached. Software may clear this bit by writing a zero.
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Package Thermal Threshold #2 Status (bit 8, RO) — Indicates whether actual package temperature is
currently higher than or equal to the value set in Package Thermal Threshold #2. If bit 8 = 0, the actual
temperature is lower. If bit 8 = 1, the actual temperature is greater than or equal to PTT#2. Quantitative
information of actual temperature can be inferred from Package Digital Readout, bits 22:16.
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Package Thermal Threshold #2 Log (bit 9, R/WC0) — Sticky bit that indicates whether the Package
Thermal Threshold #2 has been reached since the last clearing of this bit or a reset. If bit 9 = 1, the Package
Thermal Threshold #2 has been reached. Software may clear this bit by writing a zero.
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Package Power Limitation Status (bit 10, RO) — Indicates package power limit is forcing one ore more
processors to operate below OS-requested P-state. Note that package power limit violation may be caused by
processor cores or by devices residing in the uncore. Software can examine IA32_THERM_STATUS to
determine if the cause originates from a processor core (see Figure 14-27).
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Package Power Notification Log (bit 11, R/WCO) — Sticky bit that indicates any processor in the package
went below OS-requested P-state or OS-requested clock modulation duty cycle since the last clearing of this or
RESET.
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Package Digital Readout (bits 22:16, RO) — Package digital temperature reading in 1 degree Celsius
relative to the package TCC activation temperature.
0: Package TCC Activation temperature,
1: (PTCC Activation - 1) , etc. See the processor’s data sheet for details regarding PTCC activation.
A lower reading in the Package Digital Readout field (bits 22:16) indicates a higher actual temperature.
The layout of IA32_PACKAGE_THERM_INTERRUPT MSR is shown in Figure 14-30.