Hi,
Matt Wilmas wrote:
Hi all,
Expanding on the idea of passing a size other than 0 to zend_hash_init(),
when possible, which was done awhile ago in a few areas (to save
resize/rehash operations), I finally added an "array_init_size()" that can
be used instead of array_init(), likewise, when a size is known. As an
example to start, I updated these functions:
array_*: change_key_case, chunk, combine, fill, fill_keys, flip, keys
(without $search_value), map, rand, reverse, slice, splice, unique (since it
copies all entries first), values; and also compact; func_get_args;
get_defined_vars; str_split; and a couple internal uses.
heh, this optimisitations was one of the pluses mysqlnd had over
mysqli/libmysql. I am using the following macro:
#if PHP_MAJOR_VERSION < 6
#define mysqlnd_array_init(arg, field_count) \
{ \
ALLOC_HASHTABLE_REL(Z_ARRVAL_P(arg));\
zend_hash_init(Z_ARRVAL_P(arg), (field_count), NULL, ZVAL_PTR_DTOR, 0);
\
Z_TYPE_P(arg) = IS_ARRAY;\
}
#else
#define mysqlnd_array_init(arg, field_count) \
{ \
ALLOC_HASHTABLE_REL(Z_ARRVAL_P(arg));\
zend_u_hash_init(Z_ARRVAL_P(arg), (field_count), NULL, ZVAL_PTR_DTOR,
0, 0);\
Z_TYPE_P(arg) = IS_ARRAY;\
}
#endif
Those were the simplest, most obvious cases I found. :-) I didn't test
every function, but for example, the array functions that don't do much work
I found to be ~10% faster (with more than 8 elements, otherwise no resizing
would be needed). If these changes are applied, more can be done where
possible, by others, or I can and send further patches, or update them
myself if I have CVS access...
http://realplain.com/php/array_init_size.diff
http://realplain.com/php/array_init_size_5_3.diff
I was playing with initializing scripts' array( ... ) constructs with the
correct size too, but wasn't sure about the changes or what the opinion
would be. Runtime creation is improved with >8 elements, though it adds a
bit of compile overhead. Anyway, separate patches for that:
http://realplain.com/php/array_init_size_vm.diff
http://realplain.com/php/array_init_size_vm_5_3.diff
Thanks,
Matt
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