Ptolemy EVM Simulation - PowerPoint PPT Presentation

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Ptolemy EVM Simulation

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This trigger buffer by default holds 10 triggers in it in this configuration. When this buffer becomes full, RM sends an RCN message containing the 10 event ... – PowerPoint PPT presentation

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Title: Ptolemy EVM Simulation


1
Ptolemy EVM Simulation
  • Simple EVM option
  • Simple EVM which is connected to last leg of
    switch on RU side (see fig on next slide) ? the
    number of BUs is one higher than the number of
    RUs in this configuration.
  • An external Ethernet network (RCN) to broadcast
    event IDs to Readout units. An extra port
    introduced in each RU for RCN network.
  • Trigger rate mean is 12.5 kHz by default
  • Poisson by default
  • Gaussian with cut-off also possible
  • Event Fragments are 16 ? 16 kB LogNormal by
    default
  • Other standard RU options available too
  • Each BU has 8 filter nodes by default
  • Filter farm default event processing time 40 ? 4
    ms per event

2
RCN Over Myrinet
3
EVM Messages
  • BM Messages
  • CMSAllocate message is for making new event ID
    requests to BM
  • CMSClear message is for sending clear request to
    BM
  • CMSConfirm message is for assigning event IDs to
    BU.
  • RM Messages
  • CMSRCN message is for distributing event IDs to
    all read out units.

4
How it works
  • In this configuration messages are packed before
    sending them to the network. The RM puts each
    arriving trigger in its trigger buffer and does
    not broadcast it to RUs immediately. This trigger
    buffer by default holds 10 triggers in it in this
    configuration. When this buffer becomes full, RM
    sends an RCN message containing the 10 event IDs
    to all readout units.
  • Each builder unit has 256 resources by default.
    On startup each builder unit by default makes 256
    requests to BM for 256 event IDs, one at a time.
    BM fulfills these requests in batches, because
    the RM makes events available in batches and the
    BM is participating in the RU-side barrel
    shifting. The BM puts event requests into a FIFO
    and serves event IDs accordingly. Due to
    randomization in the Myrinet code the FIFO is
    unordered, such that BUs typically receive one
    event ID at a time.

5
Active Events
  • The plot on next slide shows the total number of
    active events in EVM without any involvement of
    filter nodes. We increment this total in RM on
    each arriving trigger. These events are assigned
    to BUs which make data requests to RUs. As soon
    as a particular BU builds a complete event, it
    immediately sends a clear request to BM to clear
    this event ID and clear its resource. The active
    number total is decremented each time when BM
    receives a clear event request from any BU

6
EVM with 0ms FPT
7
EVM with 40ms FPT
  • The next plot shows the active events in the
    system with 40 ms farm processing time.

8
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