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AdV-DAQ (Data Acquisition and Global Control)
masserot - 17:50 Friday 28 March 2025 (66461) Print this report
ISC_rtpc : LSC_Acl RT Task reduce the mi n elapsed time from 24us to 23us

During today’s daily meeting, people reported that the ITF lock durations are quite small and Paolo explained that can be due to the troubles of ISC data delivered in late .

Some investigations were made comparing the following channels

  • ISC_Tpro_elasped_time giving the time used at each cycle to read the data, perform the calculation and build the packets sent on the Tolm network.
  • Daq_ISCToISYS_Tolm_Send_Start  giving the transmission time of this packet . This packect is the first packet sent after the ones related to the suspension (NE,WE,BS.PR.SR.NI.WI)

This plot compare the trend of these channels for the 2024-04-01 and the 2025-03-28

  • the ISC_Tpro has increased by 1us while the  Daq_ISCToISYS_Tolm_Send_Start has increased by 2us
  • These increases are not understood

Today to ensure the correct running conditions, for the ACL taks running on the ISC_rtpc, the minimal elapsed time of the LSC_Acl task is set to 24 us, but all its operations needs only 16 us to be executed.

As a trick, the LSC_Acl server minimal elapsed time has been reduced by 1us , 23us instead of 24us . This operation has been done at the 2025-03-28-15h14m49-UTC .

This plot shows the effect of this reduction on the same channels as before:

  • the ISC_Tpro_elasped_time has recovered its previous values
  • but the Daq_ISCToISYS_Tolm_Send_Start  ones have been reduced by 1us only  
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masserot, pacaud - 18:56 Monday 31 March 2025 (66475) Print this report

After some investigation, we found that the Tolm packets sent by the Acl tasks are not transmitted in the same order as the ACL tasks are executed:

  • all the Tolm packets sent by an Acl task are transmitted in the same order as they are declared in the Acl configuration flle\
  • today when a task is re-started, it is executed at the same rank as previously for the task order but its Tolm packets are put at the end in the packet list to transmit

As reminder, Monitoring information about emission and transmission times is available for each packet exchange using the TOLM-v2 format, meaning that today these informations are not available for the  Tolm packets sent to the suspension.

For the ISC_rtpc(rtpc20),

  • Only the CALnoise, LSC_SUSP, LSC_Acl and ENVnoise Acl taks  send external Tolm packets to others devices (rtpcs, DSP, others  ). Related to the LSC_Acl ACL task, the Tolm packets related to the suspension are sent firstly and then in order  the one for ISYS named LSCToISYS,  to one for  SSFS named LSCToSSFS and as last the one to OMC named LSCToOMC
  • the 2024-10-22: all the Acl taks were restarted with the latest Acl version. This plot shows the emited time  for each packet transmitted according to its Acl task , in brackets the current order of transmission
  • the  2024-10-26, the CALnoise server was restarted . This plot show that after this operation the CALnoise Tolm packets are transmitted the last
  • the 2025-02-18-16h45 the LSC_Acl server was restarted for unknown reasons. As consequence its Tolm packets, including the suspension ones, were sent the last , see this plot.

Today, the 2025-03-31 at 12h21m-UTC, as trial to recover the expected Tolm packet transmission order ,

  • the LSC_SUSP, LSC_Acl and ENVnoise servers were restarted
  • and the minimal elapsed time for the LSC_Acl task has been reduced for 24us to 23us
  • this plot shows  the result of these operations: the expected order for the Tolm transmission has been recovered
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