From: Mark Kettenis Subject: Re: clang: enable blake3 asm optimizations on amd64? To: Stuart Henderson Cc: naddy@mips.inka.de, tech@openbsd.org Date: Sun, 18 Feb 2024 10:53:45 +0100 > Date: Sun, 18 Feb 2024 09:25:38 +0000 > From: Stuart Henderson > > On 2024/02/17 20:59, Christian Weisgerber wrote: > > From some cursory grepping, I don't think BLAKE3 is used much if > > at all in clang. So I don't know if this buys us anything. It > > does not reduce the time required by clang to compile itself. > > Any idea how to make sure that this code is exercised? > > > +.if ${MACHINE_ARCH} == "amd64" > > +SRCS+= blake3_sse2_x86-64_unix.S \ > > + blake3_sse41_x86-64_unix.S \ > > + blake3_avx2_x86-64_unix.S \ > > + blake3_avx512_x86-64_unix.S > > +.endif > > I have a suspicion that AVX512 might not work with OpenBSD. > We've had a diagnosed problem with this in node, and now a suspected > one in GHC. AVX512 doesn't work with OpenBSD. Code is supposed to check whether AVX512 has been enabled by the OS (in addition to checking the CPUID bits). But I wouldn't be surprised if there is code out there that just checks the CPUID bits and just assumes the OS has enabled support if they're present.