> On 12 May 2020, at 03:40, Lijian Zhang <lijian.zh...@arm.com> wrote: > > >> -----Original Message----- >> From: Damjan Marion <dmar...@me.com> >> Sent: 2020年5月12日 0:46 >> To: Lijian Zhang <lijian.zh...@arm.com> >> Cc: vpp-dev <vpp-dev@lists.fd.io>; nd <n...@arm.com> >> Subject: Re: [vpp-dev] clang-9 >> >> >> Hi Lijian, >> >> If I got it right, neither gcc or clang available in ubuntu 18.04 LTS are >> able to >> produce N1 optimised binaries. correct? > Yes, that's right. Support for optimized compiling for N1 starts with > gcc-9.2.0 and clang-10, which are not available in Ubuntu-18.04 yet. >> >> If yes, can we just add clang-10 from: https://apt.llvm.org to vpp build >> scripts? >> > Currently clang-10/clang-11 Aarch64 packages are not available at > apt.llvm.org yet. Arm compiler team is working on getting AArch64 packages > available at apt.llvm.org. It may take a couple of weeks. So let’s wait then. For people who wants to use N1 probably there is more sense in using ubuntu 20.04 anyway, and 20.04 is coming with clang10. >> In particular: >> >> # 10 >> deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-10 main deb-src >> http://apt.llvm.org/bionic/ llvm-toolchain-bionic-10 main >> >> >> Damjan >> >> >>> On 9 May 2020, at 12:12, Lijian Zhang <lijian.zh...@arm.com> wrote: >>> >>> Hi Damjan, >>> The patch[2] installs clang-9 in package dependencies and sets “clang-10 >> clang-9 gcc-9 cc” as the default compiler. >>> >>> The problem is, >>> 1. clang-9 does not support ‘-mtune=qdf24xx’, ‘-mtune=neoverse-n1’, ‘- >> mcpu=neoverse-n1’, so it cannot do arch-specific compiling and optimal >> function selection for those two CPUs. >>> These options requires gcc-9.2, clang-10 and any newer versions. >>> 2. The clang package servers for Ubuntu-18.04 mentioned in >> https://apt.llvm.org/ support x86, but does not support Arm64, so we cannot >> install clang-10/clang-11 directly via apt commands on Arm servers. >>> >>> I’m thinking two options, >>> 1. remove clang-9 dependency in Makefile or add for x86_64 only, so that >> users should install clang-10/clang-9 for x86 manually, and for Arm, install >> gcc- >> 9 and clang-10/clang-11(not available yet). Just like CSIT has to update gcc >> version to gcc-8.3 manually(gcc-8.3 not listed in dependencies) previously. >>> 2. there are other several workaround, >>> 2.1 install clang-10 from source code until we can do clang-10 >>> binary >> install on Ubuntu-18.04 on Arm; >>> 2.2 keep the code as it is now, although it will disable >>> multi-arch >> support for these two CPUs with clang-9; >>> 2.3 when we are developing code or doing benchmarking, we need >> to hack the code temporarily from “set(CMAKE_C_COMPILER_NAMES clang- >> 10 clang-9 gcc-9 cc)” to “set(CMAKE_C_COMPILER_NAMES clang-10 gcc-9 cc)”, >> so that multi-arch will be supported with gcc-9. >>> >>> Could you suggest on this issue? >>> Thanks. >>> From: vpp-dev@lists.fd.io <vpp-dev@lists.fd.io> On Behalf Of Damjan >>> Marion via lists.fd.io >>> Sent: 2020年4月28日 22:14 >>> To: vpp-dev <vpp-dev@lists.fd.io> >>> Subject: [vpp-dev] clang-9 >>> >>> >>> Folks, >>> >>> As there is bug in gnu assembler which is shipping with ubuntu 18.04 we are >> not able to produce working binaries with avx512 instruction set. >>> Because of that, I had to change default to avx2. reported bug[1], but it is >> ignored for a year. >>> >>> As alternative[2], I wanted to consider using clang-9 which is shipped with >> ubuntu 18.04 and seems like it is even capable of producing faster binaries >> than gcc. >>> Unfortunately, "make test" is failing at several places including vxlan, >>> ipsec >> and tcp stack[3]. >>> >>> May I ask folks who “own” that code to take a quick look? >>> >>> Thanks, >>> >>> Damjan >>> >>> [1] >>> https://bugs.launchpad.net/ubuntu/cosmic/+source/binutils/+bug/1819961 >>> [2] https://gerrit.fd.io/r/c/vpp/+/26744 >>> [3] >>> https://jenkins.fd.io/job/vpp-verify-master-ubuntu1804/3615/console >>> >>> >>> >>> >
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