![Page 1: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/1.jpg)
Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinho
7/3/2017
![Page 2: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/2.jpg)
• P-SOCRATES: Parallel SOftware framework for time-CRitical mAny-core sysTEmS• Three-year FP7 STREP project (Oct-2013, Set-2016)• Website: www.p-socrates.eu• Budget: 3.6 M€• Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP• Partners
• Industrial Advisory Board
City of Bratislava
![Page 3: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/3.jpg)
3 application use-cases– Online ads selection system– Data extraction from images– Complex Event Processing Engine
Need High Computing Performance – Software Parallelization Æ openMP 4.0– Parallel processing (multi-cores) Æ Kalray MPPA-256– Optimized hardware configuration
Need for guaranteed performance (not safety-critical)
7/3/2017 A CISTER Template
![Page 4: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/4.jpg)
4
Timing objectives
Performance requirements
![Page 5: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/5.jpg)
5
![Page 6: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/6.jpg)
6
![Page 7: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/7.jpg)
7/3/2017 A CISTER Template
Worst input data sets+
Worst resource availability=
Worst execution conditions
![Page 8: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/8.jpg)
7/3/2017 A CISTER Template
Worst input data sets+
Best resource availability
Æ Understand the importance of the impact of the shared resources
![Page 9: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/9.jpg)
7/3/2017 A CISTER Template
Not one but two WCET estimates
Isolation mode
Contention mode
![Page 10: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/10.jpg)
task
task task task
task task task
task task task
task
TIME
![Page 11: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/11.jpg)
task
TIME
task task task
task task task
task task task
task
WCETISO
![Page 12: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/12.jpg)
task task task task task task task tasktask task task task task task task task task task tasktask task task task task
16-02-2017 P-SOCRATES (Grant agreement nº 611016)
TIME
Interference generator (IG)
Interference generator (IG)
Interference generator (IG)
task task task task
Big difference between WCET-ISO and WCET-CONT
WCETCONT
![Page 13: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/13.jpg)
16-02-2017 P-SOCRATES (Grant agreement nº 611016)
#pragma omp parallel{
#pragma omp master{
(Some initialization code)#pragma omp task
{Some code for the task}#pragma omp task
{Some code for the task}(Some more code)
}
}
#include "timing.h"TIMING_ANALYSIS_INIT();#pragma omp parallel{
#pragma omp master{
TIMING_BEGIN_OF_OMP_MASTER();(Some initialization code)#pragma omp task
{Some code for the task}#pragma omp task
{Some code for the task}(Some more code)TIMING_END_OF_OMP_MASTER();
}TIMING_END_OF_OMP_PARALLEL();
}TIMING_ANALYSIS_END();
![Page 14: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/14.jpg)
16-02-2017 P-SOCRATES (Grant agreement nº 611016)
![Page 15: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/15.jpg)
16-02-2017 P-SOCRATES (Grant agreement nº 611016)
SchedCONT
ExtractWCET-CONT
Compiler phase
010001011001011100110
Compiler (BSC)
for(int i=0; i<3; i++) {for(int j=0; j<3; j++) {
if(i==0 && j==0) { // Task T1#pragma omp task depend(inout:m[i][j])
compute_block(i, j); } else if (i == 0) { // Task T2#pragma omp task depend(in:m[i][j-1], inout:m[i][j])
compute_block(i, j); } else if (j == 0) { // Task T3#pragma omp task depend(in:m[i-1][j], inout:m[i][j])
compute_block(i, j); } else { // Task T4#pragma omp task depend(in:m[i-1][j],m[i][j-1],
m[i-1][j-1], inout:m[i][j])compute_block(i, j);
Annotate the graph with the WCET in CONTENTION
WCET-CONT
SUCCESS!
Nothing we can do…
![Page 16: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/16.jpg)
SchedCONT
MapCONT
WCET-CONT
16-02-2017 P-SOCRATES (Grant agreement nº 611016)
ExtractWCET-CONT
for(int i=0; i<3; i++) {for(int j=0; j<3; j++) {
if(i==0 && j==0) { // Task T1#pragma omp task depend(inout:m[i][j])
compute_block(i, j); } else if (i == 0) { // Task T2#pragma omp task depend(in:m[i][j-1], inout:m[i][j])
compute_block(i, j); } else if (j == 0) { // Task T3#pragma omp task depend(in:m[i-1][j], inout:m[i][j])
compute_block(i, j); } else { // Task T4#pragma omp task depend(in:m[i-1][j],m[i][j-1],
m[i-1][j-1], inout:m[i][j])compute_block(i, j);
Compiler (BSC)
010001011001011100110
Annotate the graph with the WCET in CONTENTION
WCET-CONT
SUCCESS!
![Page 17: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/17.jpg)
16-02-2017 P-SOCRATES (Grant agreement nº 611016)
ExtractWCET-CONT
for(int i=0; i<3; i++) {for(int j=0; j<3; j++) {
if(i==0 && j==0) { // Task T1#pragma omp task depend(inout:m[i][j])
compute_block(i, j); } else if (i == 0) { // Task T2#pragma omp task depend(in:m[i][j-1], inout:m[i][j])
compute_block(i, j); } else if (j == 0) { // Task T3#pragma omp task depend(in:m[i-1][j], inout:m[i][j])
compute_block(i, j); } else { // Task T4#pragma omp task depend(in:m[i-1][j],m[i][j-1],
m[i-1][j-1], inout:m[i][j])compute_block(i, j);
Compiler (BSC)
010001011001011100110
Map CONT
SchedCONT
WCET-CONT
Annotate the graph with the WCET in CONTENTION
WCET-CONT
![Page 18: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/18.jpg)
16-02-2017 P-SOCRATES (Grant agreement nº 611016)
SchedISO
Map ISO
WCET-ISO
ExtractWCET-
ISO
010001011001011100110
Map CONT
SchedCONT.
FAILURE!
WCET-CONT
Annotate the graph with the WCET in ISOLATION
WCET-ISO
![Page 19: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/19.jpg)
16-02-2017 P-SOCRATES (Grant agreement nº 611016)
Sched ISO
Map ISO
WCET-ISO
ExtractWCET-
ISO
010001011001011100110
Map CONT
SchedCONT
WCET-CONT
Annotate the graph with the WCET in ISOLATION
WCET-ISO
![Page 20: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/20.jpg)
SchedRUN
WCET-RUNMap RUN
WCET-RUN
SUCCESS!
SchedRUN
WCET-RUN
SchedISO
Map ISO
WCET-ISO
ExtractWCETRUN
010001011001011100110
Annotate the graph with the WCET observed
WCET-RUN
ID time //
INFO
![Page 21: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/21.jpg)
• Two sets of results:– On the MPPA Andey– One the MPPA Bostan
![Page 22: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/22.jpg)
23-10-2013
PLATFORM SETTINGS High-perf Low-perf
Activate the D-cache Yes No
Invalidate the D-cache before running each task No -
D-cache: Stall on access No Yes
Activate the I-cache Yes No
Invalidate the I-cache before running each task No -
Memory mapping Interleaved Sequential
![Page 23: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/23.jpg)
Isolation
High-performance Low-performance
Max = 523 M Max = 3.071 M
Variation = 377 k (0,07%) Variation = 1 M (0,03%)
Contention
High-performance Low-performance
Max = 527 M Max = 27.925 M
Variation = 710 k (0,13%) Variation = 12 M (0,04%)
![Page 24: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/24.jpg)
• We couldn’t reproduce the same experiments
• Use of printf() for generating interferenceÆDisastrous results: slow down of up to
1000x
7/3/2017 A CISTER Template
![Page 25: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/25.jpg)
• The 3 application use-cases have been tested
• Overall, results seemed to confirm that static mapping and scheduling leads to less performance at runtime but more accurate analysis (the blame is on the schedulability analysis)Æ Over-estimation of carry-in and carry-outÆ New results on the way (RTSS?)
7/3/2017 A CISTER Template
![Page 26: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/26.jpg)
Investigate statistical approaches (Already fully compatible with DiagXTrem)
16-02-2017 P-SOCRATES (Grant agreement nº 611016)
5435 ms5678 ms4876 ms3874 ms7624 ms…
ISO or CONT
StationarityStationarity of the extremeIndependenceIndependence of the extreme…
Apply the EVT
WCET - ISOor WCET - CONT
![Page 27: Vincent Nelis, Patrick Meumeu Yomsi, Luís Miguel Pinhoembedded.cs.uni-saarland.de/wcet-presentations/... · • Coordinator: Luis Miguel Pinho, CISTER Research Centre, ISEP • Partners](https://reader034.vdocuments.net/reader034/viewer/2022042104/5e82a8311cb3df03b473f8da/html5/thumbnails/27.jpg)
16-02-2017 P-SOCRATES (Grant agreement nº 611016)