Re: -CURRENT compilation time

> From: David Chisnall <theraven_at_FreeBSD.org> 
> Date: Tue, 7 Sep 2021 14:51:21 +0100
> On 06/09/2021 20:34, Wolfram Schneider wrote:
> > With the option WITHOUT_TOOLCHAIN=yes the world build time is 2.5
> > times faster (real or user+sys), down from 48 min to 19.5 min real
> > time.
> 
> Note that building LLVM with the upstream CMake + Ninja build system is 
> *significantly* faster on a decent multicore machine than the FreeBSD 
> bmake-based in-tree version.

Just examples of llvm12 builds from my checking this . . .

poudriere-devel llvm12 buil times, nothing else being built, all
prerequisites already built (not that such are trivial):


amd64 ThreadRipper 1950X with 128 GiByte of RAM, optane 1.4T media, 32 FreeBSD cpus:

[00:00:07] [01] [00:00:00] Building devel/llvm12 | llvm12-12.0.1_4
[00:22:54] [01] [00:22:47] Finished devel/llvm12 | llvm12-12.0.1_4: Success

for:

---Begin OPTIONS List---
===> The following configuration options are available for llvm12-12.0.1_4:
     BE_AMDGPU=on: AMD GPU backend (required by mesa)
     CLANG=on: Build clang
     COMPILER_RT=on: Sanitizer libraries
     DOCS=on: Build and/or install documentation
     EXTRAS=on: Extra clang tools
     GOLD=on: Build the LLVM Gold plugin for LTO
     LIT=on: Install lit and FileCheck test tools
     LLD=on: Install lld, the LLVM linker
     LLDB=on: Install lldb, the LLVM debugger
     OPENMP=on: Install libomp, the LLVM OpenMP runtime library
     PYCLANG=off: Install python bindings to libclang
====> Options available for the single BACKENDS: you have to select exactly one of them
     BE_FREEBSD=off: Backends for FreeBSD architectures
     BE_NATIVE=on: Backend(s) for this architecture (X86)
     BE_STANDARD=off: All non-experimental backends
===> Use 'make config' to modify these settings
---End OPTIONS List---

Note the BE_NATIVE use. Also poudriere.conf has:

ZPOOL=zoptb
USE_TMPFS=yes
ALLOW_MAKE_JOBS=yes

For reference:

# uname -apKU
FreeBSD amd64_ZFS 13.0-RELEASE-p4 FreeBSD 13.0-RELEASE-p4 #1 releng/13.0-n244760-940681634ee1-dirty: Mon Aug 30 11:28:31 PDT 2021     root@amd64_ZFS:/usr/obj/BUILDs/13_0R-amd64-nodbg-clang/usr/13_0R-src/amd64.amd64/sys/GENERIC-NODBG  amd64 amd64 1300139 1300139

The swap/paging space stayed unused.

aarch64 Honycomb with 64 GiByte of RAM, optane 480 GiByte media, 16 FreeBSD cpus:

[00:00:15] [01] [00:00:00] Building devel/llvm12 | llvm12-12.0.1_4
[00:58:07] [01] [00:57:52] Finished devel/llvm12 | llvm12-12.0.1_4: Success

for:

---Begin OPTIONS List---
===> The following configuration options are available for llvm12-12.0.1_4:
     BE_AMDGPU=on: AMD GPU backend (required by mesa)
     CLANG=on: Build clang
     DOCS=on: Build and/or install documentation
     EXTRAS=on: Extra clang tools
     LIT=on: Install lit and FileCheck test tools
     LLD=on: Install lld, the LLVM linker
     OPENMP=on: Install libomp, the LLVM OpenMP runtime library
     PYCLANG=off: Install python bindings to libclang
====> Options available for the single BACKENDS: you have to select exactly one of them
     BE_FREEBSD=off: Backends for FreeBSD architectures
     BE_NATIVE=on: Backend(s) for this architecture (AArch64)
     BE_STANDARD=off: All non-experimental backends
===> Use 'make config' to modify these settings
---End OPTIONS List---

Note the BE_NATIVE use. Also poudriere.conf has:

ZPOOL=zopt0
USE_TMPFS="data"
ALLOW_MAKE_JOBS=yes

For reference:

# uname -apKU
FreeBSD CA72_16Gp_ZFS 13.0-RELEASE-p4 FreeBSD 13.0-RELEASE-p4 #4 releng/13.0-n244760-940681634ee1-dirty: Mon Aug 30 11:35:45 PDT 2021     root@CA72_16Gp_ZFS:/usr/obj/BUILDs/13_0R-CA72-nodbg-clang/usr/13_0R-src/arm64.aarch64/sys/GENERIC-NODBG-CA72  arm64 aarch64 1300139 1300139

The swap/paging space stayed unused.



I've not yet figured out a good way to time just an analogous
subset of buildworld . It would need to be stable/13 or main
[so: 14] targetted to involve building an llvm12 based set of
material. releng/13.0 is llvm11 based.

One point is that likely the system builds libc++ and such
but devel/llvm12 does not: devel/llvm12 likely is bound to the
system libc++ and such. This may make "analogous subset of
buildworld" harder to isolate.

So I've not made it to well-measured differences in time-used
yet.


> One of the things I'd love to prototype if I had time is a CMake-based 
> build system for FreeBSD so that we could get all of the tooling 
> integration from the compile_commands.json, reuse LLVM's (and any other 
> contrib things that use CMake) build system without having to recreate 
> it, and be able to use ninja, to build.

===
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)