Change 27406 by [EMAIL PROTECTED] on 2006/03/07 19:31:49
Two more TODOs for those with C knowledge.
Affected files ...
... //depot/perl/pod/perltodo.pod#132 edit
Differences ...
==== //depot/perl/pod/perltodo.pod#132 (text) ====
Index: perl/pod/perltodo.pod
--- perl/pod/perltodo.pod#131~27404~ 2006-03-07 11:23:14.000000000 -0800
+++ perl/pod/perltodo.pod 2006-03-07 11:31:49.000000000 -0800
@@ -372,6 +372,31 @@
might want to determine what ops I<really> are the most commonly used. And in
turn suggest evictions and promotions to achieve a better F<pp_hot.c>.
+=head2 Shrink struct context
+
+In F<cop.h>, we have
+
+ struct context {
+ U32 cx_type; /* what kind of context this is */
+ union {
+ struct block cx_blk;
+ struct subst cx_subst;
+ } cx_u;
+ };
+
+There are less than 256 values for C<cx_type>, and the constituent parts
+C<struct block> and C<struct subst> both contain some C<U8> and C<U16> fields,
+so it should be possible to move them to the first word, and share space with
+a C<U8> C<cx_type>, saving 1 word.
+
+=head2 Allocate OPs from arenas
+
+Currently all new OP structures are individually malloc()ed and free()d.
+All C<malloc> implementations have space overheads, and are now as fast as
+custom allocates so it would both use less memory and less CPU to allocate
+the various OP structures from arenas. The SV arena code can probably be
+re-used for this.
+
End of Patch.
