1. PACS SVR II – SPU HLSW Garching, 18th Jan 2007 prepared by R. Ottensamer and C. Reimers

2. PACS SVR II - SPU HLSW Garching, 18th Jan 2007 SVR I – SVR II: Overview SVR I: v12.2 FM-ILT: v12.81 SVR II: v13.1 „Cleaned“ „Problematic“ „Survive ILT“ Photometry broken, various problems tests were made with no major showstoppers better performance, CAPTEC comments, reliability, maintainability

3. PACS SVR II - SPU HLSW Garching, 18th Jan 2007 Starting Point: SVR I in June 06 SVR I: v12.2 Spectroscopy CQM data: 16 samples/mean 100 kbit/s, CPU at 100% Photometry FM testdata: 150 kbit/s CPU at 100% Various open problems Synchronization, Bol Signs,... „Problematic“ -red colour in almost all areas, especially CPU load -biggest problem: FM Bol Data so much different than expected -code is very unclean / hard to maintain -another question mark: FM Spec Data -tests would have been possible, but with some restrictions -risk of running into unknown bugs

4. PACS SVR II - SPU HLSW Garching, 18th Jan 2007 Support by MPE (1) Roland Ottensamer HLSWDOC/PAPCSS Christian Reimers Angela Baier M. Wetzstein E. Wieprecht DXSET Calfiles Next-Gen DXSET Editor SupportUM/TP/TR/...

5. PACS SVR II - SPU HLSW Garching, 18th Jan 2007 Rescue: Survival Version for the Tests -main goal: fix broken Photometry -v12.8 delivered 15.8. -major bugfix (v12.81) on 28.9. -very robust Photometry reduction scheme and LLC -bad luck: FM Spec Data lead to Autostop in best configuration -numerous smaller fixes / reactions to SPRs FM-ILT: v12.81 „Survive IMT“ Photometry 120-200 kbit/s, mostly ~145 CPU at ~55% still some minor problems timing, bugs...  Tests performed in slope fitting mode Spectroscopy FM data: 16 samples/mean goes to Autostop (CPU)

6. PACS SVR II - SPU HLSW Garching, 18th Jan 2007 Support by MPE (2) Roland Ottensamer HLSW Christian Reimers Angela Baier Second SPU HW Setup A. Mazy independent from IMT code cleaning and optimization FM Data Analyses

7. PACS SVR II - SPU HLSW Garching, 18th Jan 2007 Improvements so far: Cleaned Version -development started in Sept 06 -strict coding conventions applied and CAPTEC recommendations incorporated -cleanup of old and unused code -Autostop strategy changed -clean task communication and reassigned task priorities -checksum for compressed data -CPU performance optimization ~10% -Photometry: Nr. of frames / average can be chosen freely SVR II: v13.1 „Cleaned“ Spectroscopy FM data: 16 samples/mean 120 kbit/s, CPU at 95% Various small improvements Maintainability, Robustness, Memory, Tasks, Errors,... Photometry 120-200 kbit/s, mostly ~145 CPU at ~55%

8. PACS SVR II - SPU HLSW Garching, 18th Jan 2007 Lessons learnt: Don‘t trust...... the DSP Divisions, square roots and other math functions can have wrong results!... the compiler The default optimization flag –O2 can produce wrong code!... the drivers / library The function MEM_CopyDMToDM turned out to be a sink hole for CPU power!... bug reports Sometimes SPRs are raised just by suspicion...... hardware and documentation Detector sorting changed several times...

9. PACS SVR II - SPU HLSW Garching, 18th Jan 2007 Lessons learnt: Users don‘t use...... parameters Although a number of parameters can be set to configure compr/red, they have never been used!... detector selection Unless there is absolutely no other way, the whole array is always transmitted.... compression modes Other modes than default were hardly ever used.

10. PACS SVR II - SPU HLSW Garching, 18th Jan 2007 Next Improvements: Cleaned Version Photometry - final fine tuning of the „survival“ scheme and an adapted LLC allows 15% less TM at the cost of some CPU  125kbit/s at 70% load (TBC) tested and finalized in Feb Spectroscopy current scheme needs better adaptation to FM data current LLC needs revision/cleaning  save kbits and CPU power Header Compression - final fine tuning allows to save 1-2kbit/s and ~3% CPU at the same time Feb / Mar...... more cleaning / tuning Optimizations to save bandwidth and CPU power bugs still being found never ending? tested and finalized in Feb

11. PACS SVR II - SPU HLSW Garching, 18th Jan 2007 Goal: flight version 13.2 by February Photometry Spectroscopy averaging of 4 samples * 125 kbit/s at 70% CPU load * (remember: any number can be selected: 2, 3, 4, 5, 6, 7, 8, 9,...) 16 samples / submean 120 kbit/s at 90% CPU load