Hi again, and sorry for too much noise.. I've checked the compiler output of i386 build of blender from [1] and there's such status print:
-- SSE and SSE2 optimizations are DISABLED! Meaning, there's no SSE/SSE2 global optimization of i386 builds of Blender in Debian already (thanks to Matteo i guess :) Is there anything else here to be solved? [1] https://buildd.debian.org/status/package.php?p=blender On Mon, Nov 7, 2016 at 10:52 AM, Sergey Sharybin <ser...@blender.org> wrote: > Ah, it's Pemtium 4 where SSE2 first arrived, for a moment thought it's > Pentium Pro. My bad.. > > So for both i386 and i686 SSE2 requirement is not valid. > > Currently in Blender upstream we detect SSE/SSE2 flags based on > current CPU. Meaning, if you're builing on i686 CPU Blender should > already have global SSE2 optimization disabled. If CPU on the builder > machine supports SSE2 we can still force SSE/SSE2 optimization to be > off by passing `-DSUPPORT_SSE_BUILD=OFF -DSUPPORT_SSE2_BUILD=OFF` to > CMake. > > On Mon, Nov 7, 2016 at 10:40 AM, Matthias Klose <d...@debian.org> wrote: >> On 07.11.2016 10:32, Sergey Sharybin wrote: >>> Hi, >>> >>> Afraid the reply to #843425 was only delivered to the BTS and not easily >>> visible to you guys. >>> >>> Here's the full reply, same as [1]. Just so you know :) >>> >>> [1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=843425#10 >>> >>> >>> ---------- Forwarded message ---------- >>> From: Sergey Sharybin <ser...@blender.org> >>> Date: Mon, Nov 7, 2016 at 9:50 AM >>> Subject: Bug#843425: blender doesn't optimize for amd64 defaults >>> To: 843...@bugs.debian.org >>> >>> >>> Hi, >>> >>> From the report it's not fully clear what parts Blender those CFLAGS >>> are referencing to, but because it's all within a context of #843379 i >>> would guess we are talking about Cycles kernel here (Cycles is the >>> render engine we use in Blender). >>> >>> In this case you're partially correct: we are mainly ignoring default >>> CFLAGS but we compile 6 different CPU kernels, optimized for various >>> microarchitectures ("native" - no SSE2 on i686 / SSE2 on amd64, forced >>> SSE2, SSE3, SSE4.1, AVX and AVX2). Then during runtime we detect >>> current CPU microarchitecture and invoke kernel with highest >>> capabilities allowed on the current processor. >>> >>> This is the only way we can guarantee optimal render times on amd64. >>> Keep in mind, AVX2 can render similar scene like 2x faster than simple >>> SSE2. This is something we can not ignore for our users. >> >> well, the GCC issue was opened with a RC severity, so I assumed that >> everything >> was built using these flags. The assumption of amd64 having SSE2 enabled by >> defaults is valid. >> >>> That being said, if you have some tricky setup where we do not detect >>> capabilities correctly and Cycles tries to use unsupported kernel and >>> runs into ILLEGAL INSTRUCTION i'll be happy to look into and solve >>> that from our end. >>> >>> Now, about forcing microarchitecture in rest of Blender. We do require >>> SSE2 on amd64 and i686, but that should be all fine as far as i know >>> (amd64 always have SSE2, 32bit builds will disable SSE2 automatically >>> if current CPU does not support it). >> >> For Debian it is not ok to assume SSE2 on the i386 architecture. >> >> Matthias >> > > -- > With best regards, Sergey Sharybin -- With best regards, Sergey Sharybin _______________________________________________ pkg-multimedia-maintainers mailing list pkg-multimedia-maintainers@lists.alioth.debian.org http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/pkg-multimedia-maintainers
