"Ronald S. Bultje" <[email protected]> writes: > Hi, > > On Thu, Jul 26, 2012 at 7:30 AM, Martin Storsjö <[email protected]> wrote: >> On Thu, 26 Jul 2012, Ronald S. Bultje wrote: >> >>> Hi, >>> >>> 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. -- Måns Rullgård [email protected] _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
