TRT ROD Data Compression TRT Overview Meeting 25 June 2013 Paul T. Keener

Outline Compression status Validity gate Next steps Paul T. Keener TRT Overview 25 June 2015

Compression Status Huffman compression is still working well Run 209109: 50ns, L=7.5x1033, μ≈35, Occ=37% Total compression: 4.45 bits/straw (16.5%) Non-zero compression: 10.3 bits/straw (εNZ=0.32) Run 216432: 25ns, L=0.57x1033, μ≈10, Occ=26% Total compression: 3.43 bits/straw (12.7%) Non-zero compression: 10.5 bits/straw (εNZ=0.33) Paul T. Keener TRT Overview 25 June 2015

Stability Compare the non-zero compression for these runs using Table 6 and tables generated from these runs: Compress with Table Run Table 6 209109 216432 10.34 bits/straw 10.30 bits/straw 10.44 bits/straw 10.51 bits/straw 10.49 bits/straw 10.32 bits/straw Everything is within 2%. Expect 25ns run to be worse Patterns should be different! Paul T. Keener TRT Overview 25 June 2015

Validity Gate Suppress most info for straw that do not have LT hits in some gate Avoid compression lookups in ROD Reduce ROD->ROS bandwidth Paul T. Keener TRT Overview 25 June 2015

V-Gate Preliminary Results Run 209109, 50ns 7.5x1033 Gate (LT bitmaps, early -> late) Bar: 0000.0001 1111.1111 1100.0000 EC : 0000.0001 1111.1111 1000.0000 Total occupancy: 37.0% Non-valid straw words: 14.8% Top valid pattern: 11th most frequent, 0.37% Total Compression: 3.7 bits/straw (13.8%) Non-Zero Compression: 8.3 bits/straw (εNZ=0.26) Paul T. Keener TRT Overview 25 June 2015

V-Gate Preliminary Results (2) Run 209109, 50ns 7.5x1033, reduced readout Same gate as Full Readout mode Total occupancy: 27.3% Non-valid straw words: 5.5% Top valid pattern: 9th most frequent, 0.43% Total Compression: 3.4 bits/straw (12.4%) Non-Zero Compression: 8.2 bits/straw (εNZ=0.26) Paul T. Keener TRT Overview 25 June 2015

What to do about non-valid straws There is value in preserving the non-empty status of non-valid straws Encode with special pattern that means “non-empty, non-valid” Gives us a better view of status of detector Monitoring Debugging Other? Cost: 1 bit for ~ 15% of straws (plus a little…) Paul T. Keener TRT Overview 25 June 2015

Non-valid Straws with HT Useful to preserve this information as well Unique encoding Tiny rate Paul T. Keener TRT Overview 25 June 2015

Symbol Generation With full data, the relative rates of non-valid hit patterns can be calculated Appropriate symbol length can be determined and fixed Paul T. Keener TRT Overview 25 June 2015

Next Steps Look at realistic high μ, 25ns datasets Characterize compression scheme in general Reduced ReadOut Mode Validity Gate Check effect of Ar vs Xe. Look at possibility of running multiple tables Supported in ByteStream Converter Need to add to DAQ and DB Paul T. Keener TRT Overview 25 June 2015

Summary Compression is working well Appear to be in good shape for 100 KHz L1A Paul T. Keener TRT Overview 25 June 2015