ATLAS Event Streaming

1. ATLAS Event Streaming Game of the Goose (Dutch: Ganzenborden) (Spanish: Juego de la Oca) (Portuguese: Jogo do Ganso) Real-Time 2010 Sander Klous on behalf of the ATLAS Collaboration

2. ATLAS Event Streaming Real-Time 2010 Sander Klous on behalf of the ATLAS Collaboration

3. (Dutch: ganzenborden) Original game of the goose Game of the Goose, rules of engagement At the start of the game, each player will throw the dice. The player with the highest sum of the dice will be allowed to throw first. At each turn, a player will throw the dice and move the pawn as many fields as the sum of the dice. If you arrive at a field with a pawn of another player, you go back to the field you were coming from. In case you hit a field with a picture, please consult these rules of engagement: Number 6 (bridge): cross the bridge and continue to field number 12 Number 19 (bed and breakfast): stay and relax, so skip the next turn Number 26 (dice): throw again Number 31 (dungeon): sit and wait until one of the other players passes and pulls you out  Number 42 (woods): you got lost in the woods, go back to field number 37 Number 52 (prison): wait until one of the other players passes and gets you out of prison Number 53 (dice): throw again Number 58 (death): you died and went to goose heaven, please start over again If your picture field is not listed above you can move the same number of fields forward again. In order to win the game you have to throw the exact number to reach field number 63 in your last turn. If the number is too high, you move backwards from field 63 with the remaining number of steps. In case you hit a picture field that is not listed above, you will move backward even further, with the same number of steps as already taken. Real-Time 2010 Sander Klous on behalf of the ATLAS Collaboration

4.  0 Game of the Goose ATLAS Event Streaming Goal of the game You are an ATLAS event on an adventurous trip through the Trigger and Data Acquisition System. On your way you are faced with numerous obstacles. You can be rejected at any of the different trigger levels and you have to follow the instructions of the data acquisition components or you will never find your way to mass storage! 01 11001 0111000 110111001 010110000101 Throw the die! W H 0 Z t You are on your way to the first Level Trigger (LVL1). This hardware based system will identify if you have sufficient interesting features (known as Regions of Interest - RoIs) to move on. Once all the information has been collected from the ROS and one of the 150 Sub Farm Inputs (SFIs) is done building the event, it will be shipped to one of the 1500 Event Filter (EF) nodes over the Event Filter Network. The Event Filter only handles fully assembled events. In case one of your STs says physics or debug, you are fully built. This means you have to wait 2 turns for all the relevant information to be retrieved from the ROBs over the event builder network. In case your only ST says calibration, you are partially built (only a subset of information is required). So, you only have to wait 1 turn. Note that in the real system you can have multiple STs. You are on your way to the Level 2 Trigger (LVL2). The label physics/calibration is recorded in the event header, as LVL1 Trigger Type (L1TT). The data is read out from the FEs by the Read Out Drivers (RODs) and buffered in the Read Out Buffers (ROBs), awaiting processing by LVL2. The LVL2 receives RoI information from LVL1. it will only retrieve detector information associated with the RoIs from the ROBs via the Read Out System (ROS). Like this, the LVL2 network is capable of handling an input rate of 100 kHz. The EF Dataflow components will evaluate the LVL2 ST. In case one of your STs says physics, it is sent to the EF processors (10a). In case the only ST you have says calibration, the event is forwarded directly to the Sub Farm Outputs (SFOs – see 10b). In case of a debug ST everything is overruled. The event will go directly to the SFOs (10b). The EF can confirm the LVL2 physics ST, reject a physics ST but still accept the event for calibration or reject it completely. In case of problems, either in DAQ or in the algorithms the event will get a debug ST. Events left only with a calibration ST will be stripped from superfluous information to reduce the network load and the CPU load in the SFOs. You are a special muon calibration event produced in the LVL2 Processing units. These very small events are produced at high rate and sent directly to calibration centers all over the world via a dedicated network path. Work is ongoing to include these events in the standard event streaming. 4 10a 8 1 7b 5 9 7a Only 1 in 400 events is accepted by the LVL1 trigger. This decision is based on the information of a few subdetector systems. Information of the other subdetectors is collected, but does not participate in the decision making at LVL1. During the LVL1 decision making process, some of the information collected by the Front-end Electronics (FEs) is evaluated. Throw a die to see if you are accepted by LVL1. There are 3 options: 2 3 decision 6 In case your L1TT says calibration, you can continue to 7a. The LVL2 will simply forward the decision. Otherwise, there are 4 decision types the LVL2 can take. About 1 out of 30 events is accepted by LVL2. The decision type is stored in a label in the event header: “the StreamTag (ST)”. Besides the type the ST will contain a rough classification and some other information needed to store the events consistently. Throw a 1: Accepted for physics Throw a 2:Accepted for calibration Other numbers: Rejected, go back to start! Regions of Interest - RoI RoI Data 2% = 3GB/s decision Throw a 1 (7a): Accepted for physics Throw a 2:Accepted for calibration Throw again! Odd (7a) Throw a 3 (7a):Problems with event - debug Other numbers: Rejected, go back to start! Even (7b) Event 3GB/s, decision The 5 SFOs are the last components in the DAQ chain. This is where the actual event streaming takes place. Depending on your ST content you are stored as physics or calibration or both. If you have a debug ST you only go into the debug stream. For the physics streams a new file is opened at luminosity block (LB) boundaries. To muon calibration centers 10b Throw a 1: Accepted for physics 11 Throw a 2: Accepted for calibration ~50Hz*50kB Throw a 3:Problems with event - debug ~10Hz*1.5MB ~200Hz*1.5MB ~2kHz*1kB very low rate Other numbers: Rejected, go back to start! Congratulations You may add 1 kB to your collected total and go to start as a new event. Congratulations A calibration event can have different sizes. Throw a die and multiply with 100 kB. This you can add to your collected total. Go to start as a new event. Congratulations You may add a physics event (1.5 MB) to your collected total. A fraction of the physics events is stored in the express stream as well, for fast inspection. Throw a 1 to add another 1.5 MB to your total. Go to start as a new event. Congratulations You may add a debug event (1.5 MB) to your collected total. Go to start as a new event. Real-Time 2010 Sander Klous on behalf of the ATLAS Collaboration