2x cocotb test speed improvement by being reasonable with the GC

Author: psychogenic

microcotb

@@ -32,6 +32,13 @@
 
 import micropython
 import gc
+
+# stash the current value for garbage 
+# collection threshold (is -1/when full, by default)
+GCThreshold = gc.threshold()
+
+# start very aggressive, to keep thing defragged
+# as we read in ini and JSON files, etc
 gc.threshold(10000)
 import ttboard.util.time as time
 from ttboard.boot.demoboard_detect import DemoboardDetect
@@ -88,6 +95,7 @@ def stopClocking():
 if PowerOnSelfTest.first_boot():
     print('First boot!')
     PowerOnSelfTest.handle_first_boot()
+    gc.collect()
 
 
 
@@ -132,6 +140,9 @@ def stopClocking():
 
 print(f"tt.sdk_version={tt.version}")
 
+# end by being so aggressive on collection
+gc.threshold(GCThreshold)
+
 # to run tests easily import a module of interest, as below, and then 
 # run() it