The clang -ftrapv option is not currently implemented efficiently for the type of integer computation-intensive code used in FLAC inner loops. The code generated for -ftrapv option doesn't yet take advantage of the ARM architecture's "V" (overflow) condition code bit.
On Thursday, January 9, 2014 3:42:45 PM UTC-8, Uday Gupta wrote: > > Thanks. > > I actually made the same change after I posted the query and the stutters > went away. Looks like the clang compiler is was inefficient compared to gcc > or is it that compiler options are not getting passed to clang? > > On Thursday, January 9, 2014 3:06:08 PM UTC-8, Glenn Kasten wrote: >> >> See https://code.google.com/p/android/issues/detail?id=62562 >> comment #23 Nov 25, 2013 >> and the AOSP CL that it links to: >> https://android-review.googlesource.com/#/c/70749/ >> >> On Thursday, January 9, 2014 2:43:38 PM UTC-8, Uday Gupta wrote: >>> >>> Hi, >>> >>> Has anybody seen that FLAC decoder/Parser in Android Kitkat is taking up >>> too much CPU. >>> >>> For example to get 4096 frames it can take anywhere from 90 to 150 msec >>> on our platform. >>> >>> Only change between JB and KK seems to be in Android.mk. KK Android.mk >>> adds >>> >>> LOCAL_CLANG := true >>> LOCAL_CFLAGS += -ftrapv >>> >>> If I remove the above changes, then the time taken is consistently less >>> than or equal to ~10 msec. >>> >>> Does anybody know what this new LOCAL_CLANG option is for. >>> >>> Thanks >>> >> -- -- unsubscribe: android-porting+unsubscr...@googlegroups.com website: http://groups.google.com/group/android-porting --- You received this message because you are subscribed to the Google Groups "android-porting" group. To unsubscribe from this group and stop receiving emails from it, send an email to android-porting+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
