Asymmetric Multi Processing (AMP) using VxWorks 6.9
This tutorial is the product of recent work on the Freescale P4080 Processor. If you are not familiar with this chip, it is an 8 core beast, in the PowerPC family. (The manual is over 3500 pages!)
The figure below shows a typical AMP system. Once CPU0 has booted up, the wrload utility is used to load a specific vxWorks image from the filesystem into the memory space of the target CPU. CPU 0 has a larger portion of the available memory space, whereas the other CPUs have a smaller region to play with.
Why Use AMP?
AMP lends itself to applications that can be split into logical modules (such as control plane and data plane processing in a router), or perhaps where an increased level of security is needed on some processors (devices are assigned to processors, so the IO connections and secure applications can be seperated by the MMU). In addition, completely different OSs can be loaded onto the CPUs, so you might want a mix of linux and different builds of vxWorks.
AMP also helps when upgrading old systems by consolidating multiple boards onto a single board. The system design can remain the same, and porting becomes much easier, by taking an old application that ran on an old board, and porting it to run on on one of the CPUs in a multiprocessor system. By using AMP, there is no need to merge all the application code into a single code space. Existing Ethernet connections can even be preserved with no changes by using MIPC Network Devices (MND).
Building AMP in VxWorks
You have two options for building VxWorks images for AMP, namely using WindRiver Workbench (the GUI), or using the command line. The trouble with using Workbench is that for 8 CPUs, you have to configure eight VxWorks images individually, and this gets very tedious. Instead, create a makefile like this one, in /workspace:
############################################################################### # # makefile for amc718 AMP builds # # Ed Liversidge, Harmonic Software Systems Ltd # # http://www.harmonicss.co.uk # # This makefile demonstrates how to build an AMP system for the # Vadatech AMC718 board. This board uses an 8 core Freescale P4080 Chip # # From a vxWorks development shell, type make amp. VxWorks images will be copied # into FTP_DIR # # for Windows hosts, fix slashes WIND_HOME := $(subst \,/,$(WIND_HOME)) WIND_BASE := $(subst \,/,$(WIND_BASE)) WIND_USR := $(subst \,/,$(WIND_USR)) TOOL = gnu # all vxWorks images will get copied here for pickup FTP_DIR = C:/temp/incoming AMP0_DIR = amc718_gnu_amp0 AMP0_PROJ = $(AMP0_DIR)/$(AMP0_DIR).wpj AMP1_DIR = amc718_gnu_amp1 AMP1_PROJ = $(AMP1_DIR)/$(AMP1_DIR).wpj AMP2_DIR = amc718_gnu_amp2 AMP2_PROJ = $(AMP2_DIR)/$(AMP2_DIR).wpj AMP3_DIR = amc718_gnu_amp3 AMP3_PROJ = $(AMP3_DIR)/$(AMP3_DIR).wpj AMP4_DIR = amc718_gnu_amp4 AMP4_PROJ = $(AMP4_DIR)/$(AMP4_DIR).wpj AMP5_DIR = amc718_gnu_amp5 AMP5_PROJ = $(AMP5_DIR)/$(AMP5_DIR).wpj AMP6_DIR = amc718_gnu_amp6 AMP6_PROJ = $(AMP6_DIR)/$(AMP6_DIR).wpj AMP7_DIR = amc718_gnu_amp7 AMP7_PROJ = $(AMP7_DIR)/$(AMP7_DIR).wpj amp: amp0 amp1 amp2 amp3 amp4 amp5 amp6 amp7 amp0: vxprj create -force $(BSP) $(TOOL) $(AMP0_PROJ) vxprj bundle add $(AMP0_PROJ) BUNDLE_STANDALONE_SHELL vxprj bundle add $(AMP0_PROJ) BUNDLE_AMP_PRI vxprj component add $(BSP_PROJ) INCLUDE_PCI_BUS vxprj build $(AMP0_PROJ) cp $(AMP0_DIR)/default/vxWorks $(FTP_DIR)/vxWorks.0 amp1: vxprj create -force $(BSP) $(TOOL) $(AMP1_PROJ) vxprj bundle add $(AMP1_PROJ) BUNDLE_STANDALONE_SHELL vxprj bundle add $(AMP1_PROJ) BUNDLE_AMP_SEC vxprj component add $(AMP1_PROJ) INCLUDE_AMP_CPU_01 # need to remove INCLUDE_WDB_SYS, incompatible with AMP vxprj component remove $(AMP1_PROJ) INCLUDE_WDB_SYS vxprj build $(AMP1_PROJ) cp $(AMP1_DIR)/default/vxWorks $(FTP_DIR)/vxWorks.1 amp2: vxprj create -force $(BSP) $(TOOL) $(AMP2_PROJ) vxprj bundle add $(AMP2_PROJ) BUNDLE_STANDALONE_SHELL vxprj bundle add $(AMP2_PROJ) BUNDLE_AMP_SEC vxprj component add $(AMP2_PROJ) INCLUDE_AMP_CPU_02 # need to remove INCLUDE_WDB_SYS, incompatible with AMP vxprj component remove $(AMP2_PROJ) INCLUDE_WDB_SYS # remove networking. No devices vxprj component remove $(AMP2_PROJ) INCLUDE_NETWORK vxprj build $(AMP2_PROJ) cp $(AMP2_DIR)/default/vxWorks $(FTP_DIR)/vxWorks.2 amp3: vxprj create -force $(BSP) $(TOOL) $(AMP3_PROJ) vxprj bundle add $(AMP3_PROJ) BUNDLE_STANDALONE_SHELL vxprj bundle add $(AMP3_PROJ) BUNDLE_AMP_SEC vxprj component add $(AMP3_PROJ) INCLUDE_AMP_CPU_03 # need to remove INCLUDE_WDB_SYS, incompatible with AMP vxprj component remove $(AMP3_PROJ) INCLUDE_WDB_SYS # remove networking. No devices vxprj component remove $(AMP3_PROJ) INCLUDE_NETWORK vxprj build $(AMP3_PROJ) cp $(AMP3_DIR)/default/vxWorks $(FTP_DIR)/vxWorks.3 amp4: vxprj create -force $(BSP) $(TOOL) $(AMP4_PROJ) vxprj bundle add $(AMP4_PROJ) BUNDLE_STANDALONE_SHELL vxprj bundle add $(AMP4_PROJ) BUNDLE_AMP_SEC vxprj component add $(AMP4_PROJ) INCLUDE_AMP_CPU_04 # need to remove INCLUDE_WDB_SYS, incompatible with AMP vxprj component remove $(AMP4_PROJ) INCLUDE_WDB_SYS # remove networking. No devices. vxprj component remove $(AMP4_PROJ) INCLUDE_NETWORK vxprj build $(AMP4_PROJ) cp $(AMP4_DIR)/default/vxWorks $(FTP_DIR)/vxWorks.4 amp5: vxprj create -force $(BSP) $(TOOL) $(AMP5_PROJ) vxprj bundle add $(AMP5_PROJ) BUNDLE_STANDALONE_SHELL vxprj bundle add $(AMP5_PROJ) BUNDLE_AMP_SEC vxprj component add $(AMP5_PROJ) INCLUDE_AMP_CPU_05 # need to remove INCLUDE_WDB_SYS, incompatible with AMP vxprj component remove $(AMP5_PROJ) INCLUDE_WDB_SYS # remove networking. No devices. vxprj component remove $(AMP5_PROJ) INCLUDE_NETWORK vxprj build $(AMP5_PROJ) cp $(AMP5_DIR)/default/vxWorks $(FTP_DIR)/vxWorks.5 amp6: vxprj create -force $(BSP) $(TOOL) $(AMP6_PROJ) vxprj bundle add $(AMP6_PROJ) BUNDLE_STANDALONE_SHELL vxprj bundle add $(AMP6_PROJ) BUNDLE_AMP_SEC vxprj component add $(AMP6_PROJ) INCLUDE_AMP_CPU_06 # need to remove INCLUDE_WDB_SYS, incompatible with AMP vxprj component remove $(AMP6_PROJ) INCLUDE_WDB_SYS # remove networking. No devices. vxprj component remove $(AMP6_PROJ) INCLUDE_NETWORK vxprj build $(AMP6_PROJ) cp $(AMP6_DIR)/default/vxWorks $(FTP_DIR)/vxWorks.6 amp7: vxprj create -force $(BSP) $(TOOL) $(AMP7_PROJ) vxprj bundle add $(AMP7_PROJ) BUNDLE_STANDALONE_SHELL vxprj bundle add $(AMP7_PROJ) BUNDLE_AMP_SEC vxprj component add $(AMP7_PROJ) INCLUDE_AMP_CPU_07 # need to remove INCLUDE_WDB_SYS, incompatible with AMP vxprj component remove $(AMP7_PROJ) INCLUDE_WDB_SYS # remove networking. No devices. vxprj component remove $(AMP7_PROJ) INCLUDE_NETWORK vxprj build $(AMP7_PROJ) cp $(AMP7_DIR)/default/vxWorks $(FTP_DIR)/vxWorks.7
Using wrload
The wrload utility is executed on the vxWorks shell on the first cpu (cpu0). It will load a vxWorks image from a mounted filesystem, load the code and data onto the target cpu, and then zero the .bss segment. I have found that it can be sensitive to consecutive loads, so I tend to put taskDelays between calls. Also, the vxWorks expects some sort of bootline, and doesn’t respond well when one is missing. See the example below:
wrload ("-file host:/vxWorks.1 -cpu 1 -tsym \"*sysBootLine=dtsec(1,1) host:/vxWorks.1 h=192.168.1.100 e=192.168.1.51\" ");
taskDelay (60);
wrload ("-file host:/vxWorks.2 -cpu 2 -tsym \"*sysBootLine=dtsec(2,2) \" ");
taskDelay (60);Using ‘tip’ to get a Shell on a CPU
tip is a new function that connects to the other CPUs via a MSD (MIPC Serial Device), enabling a shell to be established where there isn’t a physical serial connection available. The MSD connections are automatically created by the BSP:
-> devs drv name 0 /null 1 /tyCo/0 1 /tyCo/1 1 /ttyMsd0 1 /ttyMsd1 1 /ttyMsd2 1 /ttyMsd3 1 /ttyMsd4 1 /ttyMsd5 1 /ttyMsd6
tip ("dev=/ttyMsd0", "dev=/ttyMsd1")
~?
[Available commands]
~.: Drop connection and exit
~l: List available sessions
~s: Switch session
~?: Print command summaryConclusion
Hopefully this has given you a flavour of using AMP under VxWorks 6.9. Of course we are available to help you with your Multiprocessor BSPs, MIPC/MSD setup and configuration, or wrestling with the beast that is the Freescale P4080. Just contact us at sales@harmonicss.co.uk or get a quick quote
This page has been translated into Serbo-Croatian : http://science.webhostinggeeks.com/asimetricni-multi-processing-amp
This page has also been translated into Blugarian : http://go-grafix.com/blog/asimetrichna-multi-obrabotka-amp-izpolzvashhi-vxworks-6-9/
