The 60K WFD readout that was introduced in MACRO 24 hours ago seems to
be affecting acquisition spy jobs by reducing their efficiency. This is
due to the fact that more ID=2 are now created. No observable overall
data volume increase was seen over the last 24 hours; this suggests that
the 60K is really marginal in creating an ID=2 buffer for every ID=1. It
was actually Jan Reynoldshon that first noticed a drop in the online
trigger rates and hinted that it might be related to the byte limit increase.
Off-line, there's nothing observable...
For the moment we decided to reduce the WFD readout byte limit to 50K for now
(RUN13796) which is still 10K on top of the 40K limit we had since last summer.
The main concern is the GC on-line analysis. Kate and Alec, do you have means of
checking the buffer collection efficiency of the ERP on-line analysis? Did you
see any drop over the last 24 hours? Please let me know.
We expect to fine tune the WFD byte limit value when the final WFD fix will
be implemented.
--Erik