Re: Feedback requested on using #defines to improve the performance of the TSRMG macro

+1 Regards, Basant. On Thu, Nov 05, 2009 at 05:22:34PM +0530, Arvind Srinivasan wrote: > 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 patch is fairly long, so rather than attach it to this email, i'll > point to it. > > It'd be great if someone could give me feedback on my changes - > > http://bitbucket.org/arvi/arviq/src/tip/arvi-16-ts_allocate_reserved_id > - for using reserved/fixed IDs for accessing thread-local storage of > frequently used/known/core subsystems. I think the changes only affect > the #ifdef ZTS codepaths. > > Thanks, > Arvi > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php >