> Hi Yueling, > > you can declare the input array as follow： > > > _MM_ALIGN16 float array[index]; > "_MM_ALIGN16" will call "__declspec(align(16))" indirectly， > > then you can use "_mm_load_ps" safely. > > BR > dianming > > 2010/11/29 pl bossart <[email protected]> > > On Mon, Nov 29, 2010 at 2:13 AM, Yue, Ling <[email protected]> wrote: >> > Hi, group >> > >> > I am looking at Meego bug #5603: >> > >> > Bug 5603 - SSE misalignment removal in gstreamer base plugin >> "audioresample" >> > >> > (http://bugs.meego.com/show_bug.cgi?id=5603) >> > >> > It's about removing the SSE misalignment in gstreamer audio resample >> > element. >> > >> > Since the input array can't ensure 16-byte aligned, when _USE_SSE is >> > configured, >> > >> > _mm_loadu_ps() will be used instead of _mm_load_ps() to load from array. >> > >> > And _mm_loadu_ps should be the main cause for high CPU usage according >> to >> > BMC#5603. >> > >> > The prototyping codes suggest removing misalignment for oversample=1 and >> 2, >> > this will reduce the hot function overhead by about 60%. >> > >> > Of course the disadvantage of removing the mis-alignment is to increase >> the >> > code complexity a lot. >> > >> > >> > >> > I plan to optimize gstreamer audio resample code now. And since this is >> a >> > common issue for speex, ffmpeg, pulseaudio etc, I wonder what's the >> > suggested method to increase SSE optimization utilization for all of >> them~ >> > >> > I googled and found someone asked about SSE optimization for moblin >> audio >> > before but I can't see the cached content. >> >> I wouldn't spend too much time fixing this bug since we want >> resampling to take place in PulseAudio, so that the rate of a specific >> stream is adjusted to the output exactly once. If you enable >> resampling in gstreamer, you have no idea what the actual output >> sampling frequency is and you will do this costly operation twice. >> remove the audioresample element from the pipeline and it should work >> just fine. Likewise all volume control operations should be handled in >> PulseAudio. >> -Pierre >> _______________________________________________ >> MeeGo-dev mailing list >> [email protected] >> http://lists.meego.com/listinfo/meego-dev >> > >
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