Filter
Top Products
www.ti.com
6.8ResourceCharacterization
ResourceCharacterization
DMARule3
EachoftheIDMA2orIDMA3methodsimplementedbyanalgorithmmustbeindependently
relocateable.
Thepragmadirectivemustbeusedtoplaceeachmethodinappropriatesubsectionstoenable
independentrelocatabilityofthemethodsbythesystemintegrator.Thetablebelowsummarizesthe
sectionnamesandtheirpurpose.
SectionNamePurpose
.text:dmaGetChannelsImplementationoftheIDMA2orIDMA3dmaGetChannelsmethod
.text:<name>ImplementationoftheIDMA2orIDMA3<name>method
Inotherwords,analgorithm'simplementationoftheIDMA2orIDMA3method<name>shouldbeplaced
inaCOFFsectionnamed".text:<name>".
TheresourcesconsumedbyalgorithmsimplementingtheIALGinterfacearerestrictedtoMIPSand
memory.TheseresourcesmustbedocumentedaccordingtotherulesdefinedinChapter4.Algorithms
implementingtheIDMA2orIDMA3interfacewillconsumeanadditionalsystemresource.Thisresource
mustalsobedocumented.
SomeDMAmanagersusesoftwarequeuingforDMAjobs.ThesesystemsneedtoknowhowmanyDMA
transfersarequeuedupsothatitcansetasidememorytoholdtheinformationforallthetransfers.Itis
importantthatthesystemintegratorknowstheworst-casedepthofthequeueofDMAjobs(numberof
concurrenttransfers)oneachlogicalchannel.
DMARule4
AllalgorithmsmuststatethemaximumnumberofconcurrentDMAtransfersforeachlogicalchannel.
Thiscanbeaccomplishedbyfillingoutatablesuchasthatshownbelow.
LogicalchannelnumberNumberofconcurrenttransfers
(depthofqueue)
03
11
Intheexampleabove,thatalgorithmrequirestwoDMAlogicalchannels;channel0willnotissuemore
thanthreeconcurrentDMAtransfers,andchannel1willnotissuemorethatoneconcurrentDMAtransfer.
ItisimportantthatsystemintegratorsbeabletowiselyoptimizetheassignmentsofDMAresources
amongalgorithms.Forexample,ifasystemintegratorchoosestoshareaphysicalDMAchannelbetween
algorithmsinapreemptivesystem,thefrequencyofthedatatransfersandthesizeofthedatatransfers
mightaffectthisassignment.
DMARule5
Allagorithmsmustcharacterizetheaverageandmaximumsizeofthedatatransfersperlogicalchannel
foreachoperation.Also,allalgorithmsmustcharacterizetheaverageandmaximumfrequencyofdata
transfersperlogicalchannelforeachoperation.
Thiscanbeaccomplishedbyfillingoutatablesuchasthatshownbelow.
LogicalDataTransfers(bytes)Frequency
Channel
OperationNumberAverageMaximumAverageMaximum
algActivate()051251211
process()0768102457
process()16412888
UseoftheDMAResource 66SPRU352G–June2005–RevisedFebruary2007
SubmitDocumentationFeedback