On 07/27/2012 06:30 PM, Ronald S. Bultje wrote: > Hi, > > On Thu, Jul 26, 2012 at 9:46 AM, Ronald S. Bultje <[email protected]> wrote: >> On Thu, Jul 26, 2012 at 9:05 AM, Måns Rullgård <[email protected]> wrote: >>> "Ronald S. Bultje" <[email protected]> writes: >>>> On Thu, Jul 26, 2012 at 7:30 AM, Martin Storsjö <[email protected]> wrote: >>>>> On Thu, 26 Jul 2012, Ronald S. Bultje wrote: >>>>>> On Thu, Jul 26, 2012 at 2:06 AM, Diego Biurrun <[email protected]> wrote: >>>>>>> On Thu, Jul 26, 2012 at 05:10:10AM +0200, Luca Barbato wrote: >>>>>>>> On 07/26/2012 04:27 AM, Ronald S. Bultje wrote: >>>>>>>>> From: "Ronald S. Bultje" <[email protected]> >>>>>>>>> >>>>>>>>> --- >>>>>>>>> libswscale/swscale.c | 2 +- >>>>>>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>>>>> >>>>>>>> >>>>>>>> Ok. >>>>>>> >>>>>>> >>>>>>> No, not OK. This is just a repackaged piece of another patch that >>>>>>> has review questions that were never answered. Until those questions >>>>>>> are settled, this cannot go in. >>>>>> >>>>>> >>>>>> I've looked at all emails in: >>>>>> http://comments.gmane.org/gmane.comp.video.libav.devel/28861 >>>>>> >>>>>> including yours: >>>>>> http://permalink.gmane.org/gmane.comp.video.libav.devel/28871 >>>>>> >>>>>> and Mans': >>>>>> http://permalink.gmane.org/gmane.comp.video.libav.devel/28863 >>>>>> >>>>>> My original mail has the "fence" part in it (simply ctrl-F in your >>>>>> browser), and neither you nor Mans respond to that particular section. >>>>>> So I'm lost now. What is the specific comment you want me to respond >>>>>> to? >>>>> >>>>> >>>>> http://article.gmane.org/gmane.comp.video.libav.devel/30834 >>>> >>>> If someone feels like rewriting swscale, I'm all supportive of that >>>> effort. For now, sws uses movntq in its inline assembly mmx/3dnow >>>> optimizations and we'll have to deal with it until someone changes it >>>> not to do that. >>>> >>>> Doing it in generic code is silly because in practice there is never >>>> any advantage to doing movntq. Thus, we should discourage its use. >>>> Adding generic versions of sfence does not contribute to that. The >>>> whole goal - back when I worked on sws - was to kill all these old >>>> mmx/3dnow optimizations and replace with modern sse2/avx, which would >>>> mean we don't need a call to sfence anymore anyways. >>> >>> I'm still missing an explanation of why sfence is needed here other than >>> movntq somehow being involved. >> >> My understanding is that if you use movntq and not sfence, the data >> may not be in the destination memory pointer by the time swScale() >> returns. >> >> But I didn't write this code. > > Ping. >
I'd let this patch land. Once there is more time would be nice rething swscale completely, I do agree. lu -- Luca Barbato Gentoo/linux http://dev.gentoo.org/~lu_zero _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
