ID: 50238
Updated by: ras...@php.net
Reported By: yoarvi at gmail dot com
-Status: Open
+Status: Analyzed
Bug Type: Performance problem
Operating System: Solaris 5.10 (SPARC)
PHP Version: 6SVN-2009-11-20 (SVN)
New Comment:
It seems silly that this would make a difference. I guess make the
change in trunk. Can't do it in the branches because it would break
binary compatibility.
Previous Comments:
------------------------------------------------------------------------
[2009-11-20 10:29:03] yoarvi at gmail dot com
Description:
------------
When compiled for multi-threaded (#ifdef ZTS ) operation, the various
subsystems in PHP use dynamically allocated (ts_allocate_id)
identifiers to index into the thread-local storage for each subsystem.
These dynamically allocated ids are used by macros such as CG, EG, PG,
AG.
The TSRMG macro is defined as:
#define TSRMG(id, type, element) (((type) (*((void ***)
tsrm_ls))[TSRM_UNSHUFFLE_RSRC_ID(id)])->element)
The PG macro is defined as:
# define PG(v) TSRMG(core_globals_id, php_core_globals *, v)
where core_globals_id is
extern PHPAPI int core_globals_id;
cc -E of
PG(connection_status) = PHP_CONNECTION_ABORTED;
translates to:
(((php_core_globals *) (*((void ***)
tsrm_ls))[((core_globals_id)-1)])->connection_status) = 1;
and cc -S of the same code results in:
.loc 1 108 0
movl %ebx, %eax
subl core_globals_id, %eax
movl (%esi), %edx
sall $2, %eax
negl %eax
movl (%edx,%eax), %eax
movw $1, 144(%eax)
I used fixed IDs instead of dynamically allocated ones and noticed a
decent improvement in performance (few percentage points) when
running a web-based ecommerce-site workload on SPARC CMT hardware.
With my changes the PG macro is defined as:
# define PG(v) TSRMG(CORE_GLOBALS_ID, php_core_globals *, v)
#define CORE_GLOBALS_ID 10
and core_globals_id is
extern PHPAPI const ts_rsrc_id core_globals_id;
cc -E of the same line of code translates to:
(((php_core_globals *) (*((void ***)
tsrm_ls))[((10)-1)])->connection_status) = 1;
cc -S (my version):
.loc 1 108 0
movl (%eax), %eax
movl 36(%eax), %eax
movw $1, 144(%eax)
The relevant discussion can be found here:
http://marc.info/?l=php-internals&m=125742200330841&w=2
Reproduce code:
---------------
The following patch implements this and incorporates the feedback
received on internals:
http://bitbucket.org/arvi/arviq/src/tip/arvi-16-ts_allocate_reserved_id
Expected result:
----------------
Improved performance when PHP is compiled with support for
multi-threading.
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=50238&edit=1
