=head1 Performance Enhancements
-XXX Changes which enhance performance without changing behaviour go here. There
-may well be none in a stable release.
+Multiple small improvements to threads:
+
+Change the internal structured of thread->params from an SV (RV) to an AV
+- so we now pass around and store the array directly, rather than creating,
+holding and dereferencing a reference to it (78b7eff).
+
+Change S_ithread_create() params from a single AV* to a pair of SV** pointers.
+This saves creating, duplicating and freeing and AV, which is only ever used for
+an internal calling convention (4cf5ea).
+
+Remove redundant hv_exists() calls from ithread_create()'s spec parser (b1faab).
+
+Skip unnecessary newAV() in ithread_create() (39f3f7).
=over 4