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Volume 2, Part 1: Processor Abstraction Layer
procedure, and the caller is expected to make another PAL_SET_PSTATE request to
transition to the desired P-state. The
transition_latency_2
field in the
pstate_buffer
returned by PAL_PSTATE_INFO indicates the time interval the caller needs to wait to
have a reasonable chance of success when initiating another PAL_SET_PSTATE call.
Implementation-specific event conditions may prevent a PAL_SET_PSTATE request from
being accepted (e.g., due to a thermal protection mechanism), in which case the PAL
procedure returns a status of
transition failure
. Such events are expected to be rare
and to happen only in abnormal situations.
It should be noted that platform power-caps do not cause a PAL_SET_PSTATE request
to fail. The requested P-state is registered with PAL, and the procedure returns a status
of
transition success
.
SCDD: If the logical processor belongs to a software-coordinated dependency domain,
the PAL_SET_PSTATE procedure will change the domain parameters resulting in a
transition to the requested P-state for all logical processors in that domain.
HCDD: If the logical processor belongs to a hardware-coordinated dependency domain,
the PAL_SET_PSTATE procedure will attempt to change the power/performance
characteristics for that logical processor. Since the power/performance characteristics
for the domain depend on the P-state settings of the other logical processors in the
domain, a PAL_SET_PSTATE call on one logical processor may result in either partial or
complete transition to the requested P-state. In case of partial transition (see
Figure 11-11, “Computation of performance_index” on page 2:321
for an example,
where the logical processor transitions from state P0 to state P3 in partial increments),
the logical processor may attempt to perform changes at a later time to the local
parameters and/or domain parameters to transition to the originally requested P-state
based on P-state transition requests on other logical processors. Software can also
approximate the behavior of a SCDD by forcing P-state transitions. See the description
of the PAL_SET_PSTATE procedure for more details.
HIDD: If the logical processor belongs to a hardware-independent dependency domain,
the PAL_SET_PSTATE procedure will attempt to change the domain parameters, which
will transition the logical processor in that domain to the requested P-state.
PAL_GET_PSTATE
: This procedure returns the performance index of the logical
processor, relative to the highest available P-state (P0). A value of 100 in P0 represents
the minimum processor performance in the P0 state. For example, if the value returned
by the procedure is 80, this indicates that the performance of the logical processor over
the last time period was 20% lower than the minimum P0 performance. For processors
that support variable P-states, it is possible for a processor to report a number greater
than 100, representing that the processor is running at a performance level greater
than the minimum P0 performance. For example, if the value returned by the processor
is 120, it indicates that the performance of the logical processor over the last time
period was 20% higher than the minimum P0 performance. The performance index is
measured over the time interval since the last PAL_GET_PSTATE call with a type
operand of 1. If the processor supports variable P-state performance then the
PAL_PROC_SET_FEATURE procedure can be used to enable or disable this feature.
Software may choose, on each invocation of the PAL_GET_PSTATE procedure, whether
to reset the internal performance measurement logic; resetting the measurement logic
Содержание ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS VOLUME 3 REV 2.3
Страница 1: ......
Страница 11: ...x Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 12: ...1 1 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part I Application Architecture Guide ...
Страница 13: ...1 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 33: ...1 22 Volume 1 Part 1 Introduction to the Intel Itanium Architecture ...
Страница 57: ...1 46 Volume 1 Part 1 Execution Environment ...
Страница 147: ...1 136 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 149: ...1 138 Volume 1 Part 2 About the Optimization Guide ...
Страница 191: ...1 180 Volume 1 Part 2 Predication Control Flow and Instruction Stream ...
Страница 230: ......
Страница 248: ...236 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 249: ...2 1 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part I System Architecture Guide ...
Страница 250: ...2 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 264: ...2 16 Volume 2 Part 1 Intel Itanium System Environment ...
Страница 380: ...2 132 Volume 2 Part 1 Interruptions ...
Страница 398: ...2 150 Volume 2 Part 1 Register Stack Engine ...
Страница 486: ...2 238 Volume 2 Part 1 IA 32 Interruption Vector Descriptions ...
Страница 749: ...2 501 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part II System Programmer s Guide ...
Страница 750: ...2 502 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 754: ...2 506 Volume 2 Part 2 About the System Programmer s Guide ...
Страница 796: ...2 548 Volume 2 Part 2 Interruptions and Serialization ...
Страница 808: ...2 560 Volume 2 Part 2 Context Management ...
Страница 842: ...2 594 Volume 2 Part 2 Floating point System Software ...
Страница 850: ...2 602 Volume 2 Part 2 IA 32 Application Support ...
Страница 862: ...2 614 Volume 2 Part 2 External Interrupt Architecture ...
Страница 870: ...2 622 Volume 2 Part 2 Performance Monitoring Support ...
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Страница 941: ...3 42 Volume 3 Instruction Reference cmp illegal_operation_fault PR p1 0 PR p2 0 Interruptions Illegal Operation fault ...
Страница 1099: ...3 200 Volume 3 Instruction Reference padd Interruptions Illegal Operation fault ...
Страница 1191: ...3 292 Volume 3 Pseudo Code Functions Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1295: ...3 396 Volume 3 Resource and Dependency Semantics ...
Страница 1296: ......
Страница 1302: ...402 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1494: ...4 192 Volume 4 Base IA 32 Instruction Reference FWAIT Wait See entry for WAIT ...
Страница 1564: ...4 262 Volume 4 Base IA 32 Instruction Reference LES Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1565: ...Volume 4 Base IA 32 Instruction Reference 4 263 LFS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1568: ...4 266 Volume 4 Base IA 32 Instruction Reference LGS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1583: ...Volume 4 Base IA 32 Instruction Reference 4 281 LSS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1647: ...Volume 4 Base IA 32 Instruction Reference 4 345 ROL ROR Rotate See entry for RCL RCR ROL ROR ...
Страница 1663: ...Volume 4 Base IA 32 Instruction Reference 4 361 SHL SHR Shift Instructions See entry for SAL SAR SHL SHR ...
Страница 1668: ...4 366 Volume 4 Base IA 32 Instruction Reference SIDT Store Interrupt Descriptor Table Register See entry for SGDT SIDT ...
Страница 1884: ...4 582 Volume 4 IA 32 SSE Instruction Reference ...
Страница 1885: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 Index ...
Страница 1886: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1898: ...INDEX Index 12 Index for Volumes 1 2 3 and 4 ...