[Halld-online] [New Logentry] High-rate performance testing

[somov at jlab.org]

Logentry Text:
--
We have tested performance of the L1/DAQ at
high rate.

Setup:
-------


Trigger type: 

25 FCAL + BCAL > 45000
PS

Configuration:
All detector, reduced size of readout windows, 
compressed mode for fadc 125, 250 

block level 40, buffer level 4
Trigger holdoffs correspond to fa125 requirements

Beam conditions:

e current - up to 500 nA
radiator - JD70-100 (58 um)
collimator - 5 mm
converter - 75 um Be


------

Some results:

Not stable DAQ performance was observed at the
trigger rate of about  70 kHz (probably at smaller
rates as well). The beam current corresponded to about 
300 nA.


Fig. 1  Live time at the trigger rate of 70 kHz

Fig. 2  Saturation of output buffers 
        (when live time drops at the previous plot)

Fig 3. Data rate from the detector (about 1 Gb/sec)


Performance of the readout electronics (read out all
modules from the crate, transmit only TI blocks through
Ethernet links) was found to be stable

Fig 4. Live time (no Ethernet transmission except TI
                  blocks)


The live time decreases to about 70-75 % when the trigger rate was 
increased to 90 kHz (400 nA current), see Fig 5.


Crates with the largest data size are:

TAGMH 28.5 k  
TAGH1 27 k
TAGM1 38 k     (data rate ~80 Mb/sec )

Note, size of the readout window should still be optimized
We also need to check threshols for the microscope

Excluding these crates from the configuration improved the
live time by 3-5%


---

This is a plain text email for clients that cannot display HTML.  The full logentry can be found online at https://logbooks.jlab.org/entry/3449004
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