Chess ReviewMay 10, 2004Berkeley, CA
Distributed Schedule-Carrying Code
Tom HenzingerSlobodan Matic
Chess Review, May 10, 2004 2
Motivation
• Distributed real-time system– static scheduling, TDMA communication
• Independent code generation by several developers– specifications from resource manager
• Code composability– component code modification does not influence other
components– check only modified code against its specification
RESOURCEMANAGER
DEVELOPER 1 DEVELOPER 2 DEVELOPER N...
Spec 1 Spec 2 Spec N
Chess Review, May 10, 2004 3
Distributing SCC
1t2
2
1
3
2t
3t
4tmode start() period 24ms {
taskfreq 2 do t1();taskfreq 2 do t2(t1);taskfreq 1 do t3(); taskfreq 3 do t4(t2,t3);
}
Giotto
dispatch(t3,5)dispatch(t2,5)
call(d2)idle(1)
dispatch(t2,1)
SCC (segment)
1t2
2
1
3
2t
3t
4t1h
2h
RESOURCEMANAGER
DEVELOPER 1 DEVELOPER 2
- task allocation- constraints (S+N type)
S+N type SCC code
- schedule code (SCC)- wcet, wcct
Chess Review, May 10, 2004 4
S+N Type and SCC
204 120 24168
21 , hcS
12 ,hcN
204 120 24168
11 ,hcN
21 ,hcN
12 ,hcS
r
r
s
0
0
3
2
t
t
1
2
3
2
t
t
1t 1t 11t 21t1t1t
r s r r s
3
2 1
t
t
3
2 1
t
t
3
21
t
t
3
2 2
t
t
04t 4t24t 24t 34t 4t
r r rr r
s r s s r
11 ,hcS
N type
SCC Modified SCC
S type
201640 248 20164 120 248
4
12
111 :, thc
3221 ,:, tthc
412 :, thc
111 :, thc
3221 ,:, tthc
412 :, thc
3t
41t 2t
4 74t
wcet3t
101t 2t
44t
wcet3 3
