#ifndef H_PERL
#define H_PERL 1
-#define PL_OP_SLAB_ALLOC
-
#ifdef PERL_FOR_X2P
/*
* This file is being used for x2p stuff.
/* See L<perlguts/"The Perl API"> for detailed notes on
* PERL_IMPLICIT_CONTEXT and PERL_IMPLICIT_SYS */
+#ifdef PERL_IMPLICIT_SYS
+/* PERL_IMPLICIT_SYS implies PerlMemShared != PerlMem
+ so use slab allocator to avoid lots of MUTEX overhead
+ */
+# ifndef PL_OP_SLAB_ALLOC
+# define PL_OP_SLAB_ALLOC
+# endif
+#endif
+
#ifdef USE_ITHREADS
# if !defined(MULTIPLICITY)
# define MULTIPLICITY