Wall Clock Time in screen and history output?

[ChristianBauerEng]

Hi All!

I'm currently running transient, 2D axisymmetric simulations of an oscillating resonator. For now I'm still in the validation and testing phase, but the results look promising!

However, I've noticed that solver performance (as in Time/Iteration) seems to degrade over runtime, so I wanted to measure that by including WALL_TIME in screen and history output. I still have trouble understanding the outputs, though.

The screen output looks like this:

+-------------------------------------
| Time_Iter| Inner_Iter| Time(sec)
+-------------------------------------
| 45330| 0| 6.3412e+02
| 45330| 5| 1.0572e+02
| 45330| 10| 5.7680e+01
+-------------------------------------
| Time_Iter| Inner_Iter| Time(sec)
+-------------------------------------
| 45340| 0| 6.3783e+02
| 45340| 5| 1.0633e+02
| 45340| 9| 6.3815e+01

The Time(sec) values of the 0th inner iteration seems to monotonically increase and represent the accumulated wall clock time since simulation start I assume. But what do the Time(sec) values for the inner iterations mean?

In the history output, the Time(sec) field looks different, as can be seen in the upper part of this figure:

In the history file, actually the last Time(sec) value of each time-iteration is printed, which also tends to increase, but not monotonically. Additionally, it seems to get reset to 0 each time output is written:

What does this value in the history output actually mean? Is it time/iteration? I've noticed a performance degradation over time, but not to this extent (I've monitored the actual runtime only sporadically, though).
If the performance degradation is in fact so severe, what could be the cause?

I'd really be happy if one of the veterans could chip in their ideas here!

[ChristianBauerEng]

Update:
It turns out, that WINDOW_START_ITER=167e3 was interpreted as 167, so time-averaging was active virtually throughout the entire simulation run. Could this be the reason for the degrading performance?