14-34 Vol. 3B
POWER AND THERMAL MANAGEMENT
•
Package Power Limit #2(bits 46:32): Sets the average power usage limit of the package domain corre-
sponding to time window # 2. The unit of this field is specified by the “Power Units” field of
MSR_RAPL_POWER_UNIT.
•
Enable Power Limit #2(bit 47): 0 = disabled; 1 = enabled.
•
Package Clamping Limitation #2 (bit 48): Allow going below OS-requested P/T state setting during time
window specified by bits 23:17.
•
Time Window for Power Limit #2 (bits 55:49): Indicates the time window for power limit #2
Time limit = 2^Y * (1.0 + Z/4.0) * Time_Unit
Here “Y” is the unsigned integer value represented. by bits 53:49, “Z” is an unsigned integer represented by
bits 55:54. “Time_Unit” is specified by the “Time Units” field of MSR_RAPL_POWER_UNIT. This field may have
a hard-coded value in hardware and ignores values written by software.
•
Lock (bit 63): If set, all write attempts to this MSR are ignored until next RESET.
MSR_PKG_ENERGY_STATUS is a read-only MSR. It reports the actual energy use for the package domain. This MSR
is updated every ~1msec. It has a wraparound time of around 60 secs when power consumption is high, and may
be longer otherwise.
•
Total Energy Consumed (bits 31:0): The unsigned integer value represents the total amount of energy
consumed since that last time this register is cleared. The unit of this field is specified by the “Energy Status
Units” field of MSR_RAPL_POWER_UNIT.
MSR_PKG_POWER_INFO is a read-only MSR. It reports the package power range information for RAPL usage. This
MSR provides maximum/minimum values (derived from electrical specification), thermal specification power of the
package domain. It also provides the largest possible time window for software to program the RAPL interface.
•
Thermal Spec Power (bits 14:0): The unsigned integer value is the equivalent of thermal specification power
of the package domain. The unit of this field is specified by the “Power Units” field of MSR_RAPL_POWER_UNIT.
•
Minimum Power (bits 30:16): The unsigned integer value is the equivalent of minimum power derived from
electrical spec of the package domain. The unit of this field is specified by the “Power Units” field of
MSR_RAPL_POWER_UNIT.
•
Maximum Power (bits 46:32): The unsigned integer value is the equivalent of maximum power derived from
the electrical spec of the package domain. The unit of this field is specified by the “Power Units” field of
MSR_RAPL_POWER_UNIT.
Figure 14-33. MSR_PKG_ENERGY_STATUS MSR
Figure 14-34. MSR_PKG_POWER_INFO Register
63
0
Reserved
Total Energy Consumed
31
32
Reserved
63
31 30
15
0
Thermal Spec Power
48 47
32
54 53
46
14
Maximum Power
16
Maximum Time window
Minimum Power