Presentation of the research work of Nicolas Dintzner, Arie van Deursen and Martin Pinzger on the evolution of feature models. This presentation was given at the VaMoS 2014 workshop.

1. EXTRACTING FEATURE MODEL
CHANGES FROM THE LINUX
KERNEL WITH FMDIFF
The 8th International Workshop on Variability
Modeling of Software-intensive Systems
Nicolas Dintzner
Delft University of Technology
Netherlands
N.J.R.Dintzner@tudelft.nl
Arie van Deursen
Delft University of Technology
Netherlands
Arie.vanDeursen@tudelft.nl
Martin Pinzger
University of Klagenfurt
Austria
martin.pinzger@aau.at

2. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
Linux kernel feature model changes
FMDiff
Feature changes
2

3. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
Feature model changes
• Major changes in a S.P.L. are mirrored by changes in its
feature model
• Details of the evolution of the Linux feature model are not
available
• Can changes in a feature models can give insights on
how the implementation changes ?
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4. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
Questions
1. What types of changes can be applied to a FM ?
2. How can we automate the extraction of feature changes
from a large scale FM?
3. How does a large scale FM change over time ?
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5. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
Linux kernel
• Very large feature model: 13k+ features
• Long history: 20+ years of existence
• Feature driven development: model “correctness”
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6. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
A feature in a Kconfig file
if ACPI
Name
config ACPI_AC
tristate "AC Adapter"
default y if ACPI
depends X86
select POWER_SUPPLY
help
This driver supports the AC Adapter object ,(...).
Type & Prompt
Default
Depends
Select
endif
(help text)
Kconfig file
Additional
structures
6

7. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
Linux feature changes
if ACPI
if ACPI
config ACPI_AC
tristate "AC Adapter"
default y if ACPI
depends X86
select POWER_SUPPLY
config ACPI_AC
boolean "AC Adapter”
default y if ACPI
default n if AIX
depends X86 || AMD
select POWER_SUPPLY
endif
endif
V1
V2
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8. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
Change classification
CHANGE
CATEGORY
CHANGE SUBCATEGORY
CHANGE TYPE
Feature
Add Remove Modify
Attribute
Depends
Default
Select
Add Remove Modify
Add Remove Modify
Add Remove Modify
Type
Prompt
Expression
References
Default value
Condition
References
Select
Condition
References
Add Remove Modify
Add Remove Modify
Add Remove Modify
Add Remove Modify
Add Remove Modify
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9. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
Classifying changes
if ACPI
config ACPI_AC
boolean "AC Adapter"
default y if ACPI
default n if AIX
depends X86 || AMD
select POWER_SUPPLY
endif
Rev.
Feature
Change type
Change
category
Change
subcategory
Old
value
New value
2
ACPI_AC
Modification
Change Attr.
Change type
“Tristate”
“Boolean”
2
ACPI_AC
Modification
Add default
Add default value
n
2
ACPI_AC
Modification
Add default
Add def. condition
AIX
2
ACPI_AC
Modification
Modify depends
Modify depends
X86
X86||AMD
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10. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
FMDiff: getting the changes
Linux repository
Feature model translation
X86
v1
X86
v2
X86
v…
FMDiff
Feature model reconstruction (EMF)
Feature model comparison (EMF Compare)
Feature change classification
Feature change repository
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11. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
From Kconfig to Kdump
1- Kconfig (original)
2- Hierarchy flattening
if ACPI
config ACPI_AC
tristate "AC Adapter"
default y if ACPI
depends X86 && ACPI
select POWER_SUPPLY
config ACPI_AC
tristate "AC Adapter"
default y if ACPI
depends X86
select POWER_SUPPLY
endif
3- Depends propagation
4- Kdump format (what we use)
config ACPI_AC
tristate "AC Adapter"
default y if X86 && ACPI
depends X86 && ACPI
select POWER_SUPPLY if X86 && ACPI
Item ACPI_AC tristate
Prompt ACPI_AC 1
Default ACPI_AC "y" "X86 && ACPI"
Depends ACPI_AC "X86 && ACPI"
ItemSelects ACPI_AC POWER_SUPPLY "X86 && ACPI”
Credits to
for Undertaker and the translation process
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12. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
Rebuilding
Kdump
Feature Model
v1
Kdump
Feature Model
v2
Feature model reconstruction (EMF)
Feature Model
(Ecore)
EMF Feature
model
Instance
v1
EMF Feature
model
Instance
v2
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13. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
Meta model
FeatureModel
Architecture (string)
Revision (string)
"contains"
0
*
Feature
Type (string)
Prompt (boolean)
Depends (string)
DependsReferences (list of strings)
Select Statement
"contains"
0
*
"contains"
0
*
Target (string)
Condition (string)
SelectConditionReferences (list of strings)
Default Statement
DefaultValue (string)
Condition (string)
DefaultValueReferences (list of strings)
DefaultValueConditionReferences (list of strings)
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14. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
Example
V1
Item ACPI_AC tristate
Depends ACPI_AC "X86 && ACPI"
…
V2
Item ACPI_AC tristate
Depends ACPI_AC “(X86 || AMD) && ACPI"
…
Feature Meta-Model
(Ecore)
Feature Model
Architecture: X86
Revision: 1
Feature Model
Architecture: X86
Revision: 2
Feature
Name: ACPI_AC
Depends: “X86 && ACPI”
Depends references:
[X86,ACPI]
Feature
Name: ACPI_AC
Depends: “(AMD || X86) && ACPI”
Depends references:
[X86,ACPI,AMD]
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15. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
EMF Compare
Differencing
Matching
Feature Model
Architecture: X86
Revision: 1
Feature
Name: ACPI_AC
Depends: “X86 && ACPI”
Depends references:
[X86,ACPI]
Feature Model
Architecture: X86
Revision: 1
Feature
Name: ACPI_AC
Depends: “X86 && ACPI”
Depends references:
[X86,ACPI]
Feature
Name: ACPI_AC
Depends: “(AMD || X86) && ACPI”
Depends references:
[X86,ACPI,AMD]
Architecture
Name
Feature
Name
Feature Model
Architecture: X86
Revision: 2
Feature Model
Architecture: X86
Revision: 2
Feature
Name: ACPI_AC
Depends: “(AMD || X86) && ACPI”
Depends references:
[X86,ACPI,AMD]
Feature Model
Architecture: X86
Attribute change: “Revision” “1”à“2”
Feature
Name: ACPI_AC
Attribute change; “Depends”; “X86 && ACPI”à“(AMD||X8…”
Attribute change; “Depends Ref.”; added “AMD”
15

16. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
Feature model changes
Feature Model
Architecture: X86
Attribute change; “Revision”; 1 à 2
Feature
Name: ACPI_AC
Attribute change; “Depends”; “X86 && ACPI” à “(AMD||X86)
Attribute change; “Depends Ref”; added “AMD”
Feature change classification
Rev.
Feature
Change type
Change
category
Change
subcategory
Old
value
New value
2
ACPI_AC
Modification
Modify depends
modify depends
X86
X86||AMD
2
ACPI_AC
Modification
Modify depends
add depends ref.
…
…
…
…
…
AMD
…
…
16

17. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
Linux kernel dataset
• 10 releases (from v2.6.38 to v3.8)
• Between 10,000 and 13,000 features in each release
• 22 to 26 architectures
• Approximately 7000 feature per architecture specific F.M.
• 1,8+ million feature change recorded
• Tool and data available
• https://github.com/NZR/Software-Product-Line-Research
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18. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
Add and remove
493
772
397
1740
612
493
750
609
1068
544
Percentage of changes (architecture average)
100%
90%
80%
70%
60%
50%
MODIFIED
REMOVED
40%
ADDED
30%
20%
10%
0%
v2.6.39
v3.0
v3.1
v3.2
v3.3
v3.4
v3.5
Linux releases
v3.6
v3.7
v3.8
18

19. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
Spread over architectures (modifications)
Series1
25
25
Series2
number of impacted architectures
Series3
Series4
Series5
20
20
Series6
Series7
Series8
15
15
Series9
Series10
Series11
10
10
Series12
Series13
Series14
5
5
Series15
Series16
Series17
0
0
2.6.39
2
3.0
3.1
4
3.2
3.3
6
3.4
Linux releases
3.5
8
3.6
3.7
10
3.8
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20. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
Questions
1. What types of changes can be applied to a FM ?
Change classification for Kconfig
2. How can we automate the extraction of feature changes
from a large scale FM?
We used Undertaker and EMF Compare
3. How does a large scale SPL FM change over time ?
Dataset available…
20

21. Extracting feature model changes from the Linux kernel with FMDiff
-
Nicolas Dintzner
Extracting feature model changes from the
Linux Kernel using FMDiff
Change classification
Tool and approach
Feature model change
Add Feature
CHANGE CATEGORY
Remove Feature
Modify Feature
Change Category
Attribute
CHANGE
SUB-CATEGORY Add
Remove Modify
Depends
Add Remove Modify
Type
Prompt
CHANGE TYPE
Add Remove Modify
Default
Add Remove Modify
Default Value
Condition
References
Expression
References
Add
Remove Modify
Add
Remove Modify
Select
Add Remove Modify
Target
Condition
References
Add Remove Modify
Tool and dataset at your disposal
https://github.com/NZR/Software-Product-LineResearch
Nicolas Dintzner
Pr. Arie Van Deursen
Pr. Martin Pinzger
Contact: Nicolas Dintzner
N.J.R.Dintzner@tudelft.nl
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