a process model of developing micro-code for a network processor
DESCRIPTION
A Process Model of Developing Micro-code for a Network Processor. 18.10.2005 Jani Koski. Author: Jani Koski Supervisor: Prof. Raimo Kantola Instructor: M.Sc Marko Lohjala. Contents. Introduction to the study Network device Network Processor (NP) Micro code for NP Why research was made - PowerPoint PPT PresentationTRANSCRIPT
1 © NOKIA 18-10-2005
A Process Model of Developing Micro-code for a Network Processor
18.10.2005 Jani Koski
Author: Jani KoskiSupervisor: Prof. Raimo Kantola Instructor: M.Sc Marko Lohjala
2 © NOKIA 18-10-2005
Contents
• Introduction to the study• Network device• Network Processor (NP)• Micro code for NP
• Why research was made• Research problem
• How to make micro code?• Micro code SW process?
• Research method• Search best SW model from literature• Let’s take to account the nature of Micro code, environment, etc
=> case study
• Case study• Project analysis• NP analysis• Micro code analysis• The result
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Network device
Hostprocessing
PHY
Parcing/framing
Lookup/classification
Modification
Quenue
Processing(slow path)Compressing/Encryption
Switching fabric
Transmission medium
Packet processing
NPSTM-1
FastEthernet
GigaEthernet
Network Processor (NP)
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Network Processor (NP)
NPSTM-1
FastEthernet
GigaEthernet
Classifier Traffic Mgnt and shaping
State machine
Ou
tput
Inpu
t
PacketssentPackets
arrive
Policing results
Micro code
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Why research was made
• Previously micro code was done by Agere Systems
• But also the Nokia had knowledge to produce the micro code
• Faster SW integration if Nokia produce the micro code it selves?
• Nokia did not have any process for producing APP550 specific micro code
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Research problem
QIn what level “micro code SW process” should be investigated?
QSchedule of micro code SW process? When to implement micro code?
QHow to implement micro code to support HW-test?
QThe nature of micro code? How does it differ from traditional coding?
QHow do we test micro code? What tools do we have?
QCan we reuse some generic SW process models using literature?
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Answers (Q1)
Q In what level should question “micro code SW process?” be investigated?
A The level is Generic micro code SW process model.
A It means that we will find different generic SW process models (e.g. Spiral model, Water Fall model) from literature and approach our question from academic point of view.
A We avoid “copy-paste” method and existing Nokia SW process models are not used
A To choose best model from literature we need information about nature of Micro code.
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Answers (Q2)
Q Schedule of micro code SW process? When to implement micro code? Somewhere middle of HW and SW schedule?
A HW must get some preliminary version from micro code to make their HW tests (HW MT). Without micro code it is not possible.
A Schedule is most likely following:
SW
OS
HW
Micro codeTime/t
simulation
Test board (e.g. Hydra)
Test version tosupport HW test
Final version
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Answers (Q2) cont.
Q How to map the micro code SW process to our HW milestone?
A We have different kind of SW to be integrated:• OS, SW, Micro code
A For micro code at least four different “versions” can be identified:1. Preliminary micro code version 1 test with simulator2. Preliminary micro code version 2 test with test board3. Preliminary micro code version 3 to support HW test4. Final micro code version 4 with all feature support
SW
OS
HW
Micro codeTime/t
simulation
Test board (e.g. Hydra)
Test version tosupport HW test
Final version
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Answers (Q3)
Q How to implement micro code to support HW-test?
A We need some input from HW group to make sufficient first version from micro code to HW group.
A After knowing requirements we can implements micro code.
1
2
3
1
2
SW_v0.1
SW_v0.2
SW_v1.0Rel 1.0
SW_v2.1
SW_v2.2
Main branch/main/dev1/
”HW test” branch/main/test/
Merge HW testcode to final code
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Answers (Q4)
Q The nature of Micro code? How does it differ from traditional coding (like C, C++, Java) or does it differ at all?
A Yes, micro code differs from traditional coding. If we compare e.g. to C language and SW done with that, micro code is:
o Usually less code lines than in C=> no big resources needed
o Available memory is usually small Big micro code software not possible Available memory can not be used as in C (we have no
pointers).o Instruction set smaller than in Co Same code editors can be used (emacs, UltraEdit)o Micro code can be simulated with simulator (SPA if APP is used)
o Note that there are different versions of APP and simulators!
o Debugging is different (and difficult) in micro code (printf(“Hello world”); is not possible).
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Answers (Q4) cont.
Q The nature of Micro code? How does it differ from traditional coding (like C, C++, Java) or does it differ at all?
A Yes, micro code differs from traditional coding. If we compare e.g. to C language and SW done with that, micro code is (APP):
o Real time programmingo In micro code we have only very limited time to use per
received cell or PDUo In micro code we may have dynamic changing code (using
searching trees). Trees are usually modified by some host processor.
o Micro code compiler gives similar kind of warning and error than e.g. gcc.
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Answers (Q5)
Q How do we test micro code? What tools do we have?
A HW can not be ready if it is not verified by HW MT (HardWare Module Testing). HW MT needs some preliminary micro code for testing. But how do we create micro code if we can not test that in some HW?
Chicken-Egg problem
A Because we do not have HW ready for testing we need simulator. Usually manufacturer can offer a simulator for their NP (e.g. SPA for APP). But simulator may have some SW bugs and we can not be 100% sure that micro code is really working.
We could use also “test boards” that include the real NP (delivered by manufacturer). E.g Agere’s Hydra.
A When our HW is ready we will continue testing with that. Testing equipment needed! (e.g. packet generator etc.) Simulator can be still used.
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Answers (Q6)
Q Can we reuse some generic SW process models using literature?
A Generic SW process models from literature
A Other SW process models.
A Agility methods in SW process models.
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Choosing the SW process
A Generic SW process models from literature :1. Water fall model is too heavy process model for
micro code. It produce lot of documentation and it’s applicable for big process
2. Evolution model is a good model for producing complex SW. SW is produced iterative but that will cause lot of updates to documentation. The biggest disadvantage is poor SW architecture caused by this model.
3. Component model uses old SW as much as possible. This leads SW design where SW components are very generic. However, the result is usually big SW because code is not optimized.
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Choosing the SW process
A Other SW process models:1. Prototyping is very useful model for example
finding out critical capacity questions2. RUP (Rational Unified Process) is a combination of
Water fall, Evolution Component models3. Formal models is based on mathematical forms4. 4 GT models are higher level tools for generating
code5. “Code and fix” –model is a poor model6. Spiral model is a model for minimizing risks
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Choosing the SW process
A Agility methods in SW process models:1. XP (Extreme Programming) was used as a main
model for micro code2. RAD (Rapid Application Development) is developed
from 4 GT models
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XP-model
• Based on iteration
• Pair programming
• For small projects (e.g. about 2-12 programmers)
• Promotes team work
• Stresses customer satisfaction (e.g. other project)
• Customer is part of the process
• Developers, managers and customers are working together
• Design unit test case before coding
• Automatic testing
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The Micro code SW process
Choosingnext feature
Featurepriorisation
Featurerequirements
Feature design,coding, testing
System testing
Componentanalyze
documentation DB
Micro
cod
e d
esig
n d
ocu
menta
tion
Micro
cod
e re
quire
ment d
ocu
menta
tion
Host
pro
cess
or
inte
rface
sp
eci
fica
tion
HW
te
st s
peci
fica
tion
Pro
duct
req
uir
em
ent
speci
fica
tion
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Detailed micro code SW process
Choosingnext feature
Featurepriorisation
Featurerequirements
Feature design,coding, testing
System testing
Componentanalyze
Design of FPL-program test
FPL-program coding
FPL-program testing
Micro code testing
Feature analyze
Design of C-NP -program test
C-NP -program coding
C-NP -program testing
Choosing next feature
Feature design, coding, testing
Component analyze
System testing
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Conclusion
• Feature IP QoS was implemented by using the micro code SW process
• Micro code SW process works but is it efficient?• Requires measurements later (out of this thesis)
• Component model was used but XP model is dominating
• Pair programming in XP model may face some problems. E.g cultural and behavioural problems
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Questions?
Comments?
Any new ideas?
Thank you!