I ran my usual set of benchmarks of libav compiled with the current gcc releases (hand-written assembly disabled). The results are in this spreadsheet: https://docs.google.com/spreadsheet/ccc?key=0AguHvNGaLXy9dHExeWZ1YWZ1c0s2VnpJRkl2bVRPU2c
First the good news, almost everything is faster with 4.6+ than with linaro-4.5. The bad news is that some things have regressed since 4.6, even if not all the way back to 4.5 levels. A few especially problematic pieces stand out: - The mp3 test performs 5-15% worse. This regression is (mostly) attributable to the ff_mpadsp_apply_window_fixed [1] function. We have looked at this one before. - FLAC is 9% slower in upstream 4.7/4.8 compared to Linaro releases. Here flac_lpc_16_c [2] and flac_decorrelate_indep_c_16 [3] are mainly to blame. - MPEG2/MPEG4 decoding is ~10% slower with vectorisation turned on. The culprit here is ff_simple_idct_8_c [4] function. - H.264 and DTS seem 1-2% slower, although this could be just noise. - Code size has increased by ~10% in all post-4.6 releases. In all cases, compiled with -O3 -mcpu=cortex-a9. The vectorised builds all use -fvect-cost-model. Without this flag the results are much worse. [1] http://git.libav.org/?p=libav.git;a=blob;f=libavcodec/mpegaudiodsp_template.c;h=8a521d9d0ca0798c75f9cdfdf9887aa0c33c746a;hb=HEAD#l121 [2] http://git.libav.org/?p=libav.git;a=blob;f=libavcodec/flacdsp.c;h=a2e335b4de81188a61e1d62e970aa23204812973;hb=HEAD#l43 [3] http://git.libav.org/?p=libav.git;a=blob;f=libavcodec/flacdsp_template.c;h=0affe22ddb76325682aef46731722b068dd3a791;hb=HEAD#l51 [4] http://git.libav.org/?p=libav.git;a=blob;f=libavcodec/simple_idct_template.c;h=3c855e3825dc7b87747b8217b9955eae83528246;hb=HEAD#l315 -- Mans Rullgard / mru _______________________________________________ linaro-toolchain mailing list linaro-toolchain@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-toolchain
