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author | Joel Sherrill <joel.sherrill@OARcorp.com> | 1998-10-19 19:31:22 +0000 |
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committer | Joel Sherrill <joel.sherrill@OARcorp.com> | 1998-10-19 19:31:22 +0000 |
commit | 9d10023164ae13c1a33d67e256005d5f4404fc87 (patch) | |
tree | 9d951d4644ffc69d37f3133537d9702e2f4f18f6 /doc/supplements/powerpc/timedata.t | |
parent | Renamed memmodel.texi to memmodel.t. (diff) | |
download | rtems-9d10023164ae13c1a33d67e256005d5f4404fc87.tar.bz2 |
Renamed
Diffstat (limited to 'doc/supplements/powerpc/timedata.t')
-rw-r--r-- | doc/supplements/powerpc/timedata.t | 142 |
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diff --git a/doc/supplements/powerpc/timedata.t b/doc/supplements/powerpc/timedata.t deleted file mode 100644 index f5ea26e7fc..0000000000 --- a/doc/supplements/powerpc/timedata.t +++ /dev/null @@ -1,142 +0,0 @@ -@c -@c Timing information for PSIM -@c -@c COPYRIGHT (c) 1988-1998. -@c On-Line Applications Research Corporation (OAR). -@c All rights reserved. -@c -@c $Id$ -@c - -@include ../../common/timemac.texi -@tex -\global\advance \smallskipamount by -4pt -@end tex - -@ifinfo -@node RTEMS_BSP Timing Data, RTEMS_BSP Timing Data Introduction, Timing Specification Terminology, Top -@end ifinfo -@chapter RTEMS_BSP Timing Data -@ifinfo -@menu -* RTEMS_BSP Timing Data Introduction:: -* RTEMS_BSP Timing Data Hardware Platform:: -* RTEMS_BSP Timing Data Interrupt Latency:: -* RTEMS_BSP Timing Data Context Switch:: -* RTEMS_BSP Timing Data Directive Times:: -* RTEMS_BSP Timing Data Task Manager:: -* RTEMS_BSP Timing Data Interrupt Manager:: -* RTEMS_BSP Timing Data Clock Manager:: -* RTEMS_BSP Timing Data Timer Manager:: -* RTEMS_BSP Timing Data Semaphore Manager:: -* RTEMS_BSP Timing Data Message Manager:: -* RTEMS_BSP Timing Data Event Manager:: -* RTEMS_BSP Timing Data Signal Manager:: -* RTEMS_BSP Timing Data Partition Manager:: -* RTEMS_BSP Timing Data Region Manager:: -* RTEMS_BSP Timing Data Dual-Ported Memory Manager:: -* RTEMS_BSP Timing Data I/O Manager:: -* RTEMS_BSP Timing Data Rate Monotonic Manager:: -@end menu -@end ifinfo - -@ifinfo -@node RTEMS_BSP Timing Data Introduction, RTEMS_BSP Timing Data Hardware Platform, RTEMS_BSP Timing Data, RTEMS_BSP Timing Data -@end ifinfo -@section Introduction - -The timing data for RTEMS on the RTEMS_BSP target -is provided along with the target -dependent aspects concerning the gathering of the timing data. -The hardware platform used to gather the times is described to -give the reader a better understanding of each directive time -provided. Also, provided is a description of the interrupt -latency and the context switch times as they pertain to the -PowerPC version of RTEMS. - -@ifinfo -@node RTEMS_BSP Timing Data Hardware Platform, RTEMS_BSP Timing Data Interrupt Latency, RTEMS_BSP Timing Data Introduction, RTEMS_BSP Timing Data -@end ifinfo -@section Hardware Platform - -All times reported in this chapter were measured using the PowerPC -Instruction Simulator (PSIM). PSIM simulates a variety of PowerPC -6xx models with the PPC603e being used as the basis for the measurements -reported in this chapter. - -The PowerPC decrementer register was was used to gather -all timing information. In real hardware implementations -of the PowerPC architecture, this register would typically -count something like CPU cycles or be a function of the clock -speed. However, with PSIM each count of the decrementer register -represents an instruction. Thus all measurements in this -chapter are reported as the actual number of instructions -executed. All sources of hardware interrupts were disabled, -although traps were enabled and the interrupt level of the -PowerPC allows all interrupts. - -@ifinfo -@node RTEMS_BSP Timing Data Interrupt Latency, RTEMS_BSP Timing Data Context Switch, RTEMS_BSP Timing Data Hardware Platform, RTEMS_BSP Timing Data -@end ifinfo -@section Interrupt Latency - -The maximum period with traps disabled or the -processor interrupt level set to it's highest value inside RTEMS -is less than RTEMS_MAXIMUM_DISABLE_PERIOD -microseconds including the instructions which -disable and re-enable interrupts. The time required for the -PowerPC to vector an interrupt and for the RTEMS entry overhead -before invoking the user's trap handler are a total of -RTEMS_INTR_ENTRY_RETURNS_TO_PREEMPTING_TASK -microseconds. These combine to yield a worst case interrupt -latency of less than RTEMS_MAXIMUM_DISABLE_PERIOD + -RTEMS_INTR_ENTRY_RETURNS_TO_PREEMPTING_TASK microseconds at -RTEMS_MAXIMUM_DISABLE_PERIOD_MHZ Mhz. -[NOTE: The maximum period with interrupts disabled was last -determined for Release RTEMS_RELEASE_FOR_MAXIMUM_DISABLE_PERIOD.] - -The maximum period with interrupts disabled within -RTEMS is hand-timed with some assistance from RTEMS_BSP. The maximum -period with interrupts disabled with RTEMS occurs was not measured -on this target. - -The interrupt vector and entry overhead time was -generated on the RTEMS_BSP benchmark platform using the PowerPC's -decrementer register. This register was programmed to generate -an interrupt after one countdown. - -@ifinfo -@node RTEMS_BSP Timing Data Context Switch, RTEMS_BSP Timing Data Directive Times, RTEMS_BSP Timing Data Interrupt Latency, RTEMS_BSP Timing Data -@end ifinfo -@section Context Switch - -The RTEMS processor context switch time is RTEMS_NO_FP_CONTEXTS -instructions on the RTEMS_BSP benchmark platform when no floating -point context is saved or restored. Additional execution time -is required when a TASK_SWITCH user extension is configured. -The use of the TASK_SWITCH extension is application dependent. -Thus, its execution time is not considered part of the raw -context switch time. - -Since RTEMS was designed specifically for embedded -missile applications which are floating point intensive, the -executive is optimized to avoid unnecessarily saving and -restoring the state of the numeric coprocessor. The state of -the numeric coprocessor is only saved when an FLOATING_POINT -task is dispatched and that task was not the last task to -utilize the coprocessor. In a system with only one -FLOATING_POINT task, the state of the numeric coprocessor will -never be saved or restored. When the first FLOATING_POINT task -is dispatched, RTEMS does not need to save the current state of -the numeric coprocessor. - -The following table summarizes the context switch -times for the RTEMS_BSP benchmark platform: - -@include timetbl.texi - -@tex -\global\advance \smallskipamount by 4pt -@end tex - - |