Summary:	ASTERISK-06921: [patch] some little G.711 optimizations
Reporter:	Denis Smirnov (mithraen)	Labels:
Date Opened:	2006-05-08 10:51:56	Date Closed:	2006-05-20 08:38:18
Priority:	Minor	Regression?	No
Status:	Closed/Complete	Components:	Core/CodecInterface
Versions:		Frequency of Occurrence
Related Issues:
Environment:		Attachments:	( 0) g711.2006-05-20.patch ( 1) while-vs-for-test.tar.gz
Description:	This patch change for( i=0; i < xxx; i++) to while ( i-- ), because second is faster on x86. x86 processors has decremt operator which set flag zero/non zero, that can be tested. I upload patch, and small demo for change in asm code with this optimization
Comments:	By: Tilghman Lesher (tilghman) 2006-05-08 11:52:04 Is this also faster on the other architectures that we target, such as PowerPC? By: Denis Smirnov (mithraen) 2006-05-09 08:59:58 Identical or faster. If this architecture has "decrement and compare to zero" command (x86 hasn't decrement _without_ compare to zero), it would be faster. If not -- it would decrement and compare, like with for. If you have access to PowerPC, please, try to run makefile in while-vs-for-test.tar.gz, and see or send me resulting asm code. I hasn't powerpc cross compiler. By: Denis Smirnov (mithraen) 2006-05-16 11:44:01 What about this patch? By: Russell Bryant (russell) 2006-05-19 22:20:42 Mithraen, did you mean to post a new patch when you made that last bug note? By: Jeffrey C. Ollie (jcollie) 2006-05-19 22:30:49 What would really be interesting would be to use liboil for some of these cpu-intensve inner loops: http://liboil.freedesktop.org/wiki/ By: Russell Bryant (russell) 2006-05-19 22:38:41 1) Why did you change BUFFER_SAMPLES in codec_a_mu.c? 2) Could you please change the format of while( x-- ) to be while (x--).  That will better match the coding guidelines. By: Denis Smirnov (mithraen) 2006-05-20 08:22:54 Patch updated with without buffer lenght change and with while( x-- ) -> while(x--) change. About liboil -- yes, this is interesting, but only if using of this considered as standart in asterisk development. And I think, that better is writing some simple inline functions, that can be use liboil _or_ intel IPP lib. By: Russell Bryant (russell) 2006-05-20 08:38:17 added to the trunk in revision 29018, thanks!