Add libbpf as a submodule (take 2) #168

jordalgo · 2024-02-29T22:11:35Z

This is to potentinally reduce issues with folks
using different versions of libbpf at runtime.

This also:

makes static linking of libbpf the default
adds steps in meson setup to fetch libbpf and make it

jordalgo · 2024-02-29T22:12:21Z

I tested a bunch but if folks want to experiment with the setup:

git clone https://github.com/jordalgo/scx.git --branch libbpf-submodule-2

htejun · 2024-02-29T22:18:03Z

meson.build

+    if get_option('libbpf_a') == ''
+      message('Checking out libbpf submodule and building it...')
+      run_command('git', 'submodule', 'update', '--init', '--recursive', check: true)
+      run_command('make', '-C', 'libbpf/src', check: true)


Shouldn't it pass cc and other build options (CFLGAS, LDFLAGS) down to make? Also, what about build concurrency? Can we specify a reasonable -j option by default?

Doesn't cc (and the other build options) get picked up by make in the same way that meson grabs it with meson.get_compiler? When I'm building locally if I run setup with the env CC=clang then it builds libbpf with clang as well (as opposed to gcc which is my default).

Can we specify a reasonable -j option by default?

Sure. Is there a decent middle ground here? -j32 ?

Doesn't cc (and the other build options) get picked up by make in the same way that meson grabs it with meson.get_compiler? When I'm building locally if I run setup with the env CC=clang then it builds libbpf with clang as well (as opposed to gcc which is my default).

Well, depends on how the flags are specified, I think. e.g. I don't think CFLAGS is the only way to pass in compiler flags to meson. Best to explicitly set relavent enviroments as when we're calling e.g. cargo.

Can we specify a reasonable -j option by default?

Sure. Is there a decent middle ground here? -j32 ?

Add nproc as dependency and run that to get the answer?

e.g. I don't think CFLAGS is the only way to pass in compiler flags to meson

In looking at the docs, I think this is the recommended way to do this: https://mesonbuild.com/howtox.html#set-extra-compiler-and-linker-flags-from-the-outside-when-eg-building-distro-packages

I think if there are specific flags that we want to pass to either clang or gcc then we have to do that explicitly in the build file. e.g. do we want to check if the compiler is clang and pass the BPF_BASE_CFLAGS ? Maybe I'm missing something.

htejun · 2024-02-29T22:20:11Z

meson.build

+endif
+
+if libbpf_a != ''
+  if not fs.exists(libbpf_a)


So, we end up running this once. Wouldn't it be better to have a more permanent way of detecting the default case (it can just be a bool from the above if/else block too) and run make each time?

Good call. If people pull and we've update the submodule we'd want to run it again.

meson.options

This is to potentinally reduce issues with folks using different versions of libbpf at runtime. This also: - makes static linking of libbpf the default - adds steps in `meson setup` to fetch libbpf and make it

ptr1337 · 2024-03-01T21:09:01Z

LGTM.
Tested locally:

The Meson build system
Version: 1.3.2
Source dir: /tmp/makepkg/scx-scheds-git/src/scx
Build dir: /tmp/makepkg/scx-scheds-git/src/scx/build
Build type: native build
Project name: sched_ext schedulers
Project version: 0.1.7
C compiler for the host machine: cc (gcc 13.2.1 "cc (GCC) 13.2.1 20230801")
C linker for the host machine: cc ld.bfd 2.42.0
Host machine cpu family: x86_64
Host machine cpu: x86_64
Program clang found: YES (/usr/bin/clang)
Program bpftool found: YES (/usr/bin/bpftool)
Program cargo found: YES (/usr/bin/cargo)
Program /tmp/makepkg/scx-scheds-git/src/scx/meson-scripts/get_clang_ver found: YES (/tmp/makepkg/scx-scheds-git/src/scx/meson-scripts/get_clang_ver)
Program /tmp/makepkg/scx-scheds-git/src/scx/meson-scripts/bpftool_build_skel found: YES (/tmp/makepkg/scx-scheds-git/src/scx/meson-scripts/bpftool_build_skel)
Program /tmp/makepkg/scx-scheds-git/src/scx/meson-scripts/get_sys_incls found: YES (/tmp/makepkg/scx-scheds-git/src/scx/meson-scripts/get_sys_incls)
Program /tmp/makepkg/scx-scheds-git/src/scx/meson-scripts/test_sched found: YES (/tmp/makepkg/scx-scheds-git/src/scx/meson-scripts/test_sched)
Program /tmp/makepkg/scx-scheds-git/src/scx/meson-scripts/build_libbpf found: YES (/tmp/makepkg/scx-scheds-git/src/scx/meson-scripts/build_libbpf)
Program /tmp/makepkg/scx-scheds-git/src/scx/meson-scripts/cargo_fetch found: YES (/tmp/makepkg/scx-scheds-git/src/scx/meson-scripts/cargo_fetch)
meson.build:45: WARNING: clang >= 17 recommended (/usr/bin/clang ver=16.0.6)
Program jq found: YES (/usr/bin/jq)
Program make found: YES (/usr/bin/make)
Program nproc found: YES (/usr/bin/nproc)
Message: Updating libbpf submodule
Library elf found: YES
Library z found: YES
Library zstd found: YES
Message: cpu=x86_64 bpf_base_cflags=['-g', '-O2', '-Wall', '-Wno-compare-distinct-pointer-types', '-D__TARGET_ARCH_x86', '-mcpu=v3', '-mlittle-endian', '-idirafter /usr/lib/clang/16/include', '-idirafter /usr/local/include', '-idirafter /usr/include']
Run-time dependency threads found: YES
Dependency threads found: YES unknown (cached)
Dependency threads found: YES unknown (cached)
Dependency threads found: YES unknown (cached)
Dependency threads found: YES unknown (cached)
Dependency threads found: YES unknown (cached)
Dependency threads found: YES unknown (cached)
Found pkg-config: YES (/usr/bin/pkg-config) 2.1.0
Run-time dependency systemd found: YES 255
Build targets in project: 17

sched_ext schedulers 0.1.7

  User defined options
    auto_features     : enabled
    buildtype         : plain
    libexecdir        : lib
    prefix            : /usr
    sbindir           : bin
    wrap_mode         : nodownload
    python.bytecompile: 1
    b_pie             : true

Found ninja-1.11.1 at /usr/bin/ninja
INFO: autodetecting backend as ninja                                                                                                                                                                                                        
INFO: calculating backend command to run: /usr/bin/ninja -C /tmp/makepkg/scx-scheds-git/src/scx/build
ninja: Entering directory `/tmp/makepkg/scx-scheds-git/src/scx/build'
[3/37] Generating libbpf with a custom command
In function ‘elf_close’,
    inlined from ‘elf_close’ at elf.c:55:6,
    inlined from ‘elf_find_func_offset_from_file’ at elf.c:386:2:
elf.c:59:9: warning: ‘elf_fd.elf’ may be used uninitialized [-Wmaybe-uninitialized]
   59 |         elf_end(elf_fd->elf);
      |         ^~~~~~~~~~~~~~~~~~~~
elf.c: In function ‘elf_find_func_offset_from_file’:
elf.c:379:23: note: ‘elf_fd.elf’ was declared here
  379 |         struct elf_fd elf_fd;
      |                       ^~~~~~
In function ‘elf_close’,
    inlined from ‘elf_close’ at elf.c:55:6,
    inlined from ‘elf_find_func_offset_from_file’ at elf.c:386:2:
elf.c:60:9: warning: ‘elf_fd.fd’ may be used uninitialized [-Wmaybe-uninitialized]
   60 |         close(elf_fd->fd);
      |         ^~~~~~~~~~~~~~~~~
elf.c: In function ‘elf_find_func_offset_from_file’:
elf.c:379:23: note: ‘elf_fd.fd’ was declared here
  379 |         struct elf_fd elf_fd;
      |                       ^~~~~~
At top level:
cc1: note: unrecognized command-line option ‘-Wno-unknown-warning-option’ may have been intended to silence earlier diagnostics
In function ‘elf_close’,
    inlined from ‘elf_close’ at elf.c:55:6,
    inlined from ‘elf_find_func_offset_from_file’ at elf.c:386:2:
elf.c:59:9: warning: ‘elf_fd.elf’ may be used uninitialized [-Wmaybe-uninitialized]
   59 |         elf_end(elf_fd->elf);
      |         ^~~~~~~~~~~~~~~~~~~~
elf.c: In function ‘elf_find_func_offset_from_file’:
elf.c:379:23: note: ‘elf_fd.elf’ was declared here
  379 |         struct elf_fd elf_fd;
      |                       ^~~~~~
In function ‘elf_close’,
    inlined from ‘elf_close’ at elf.c:55:6,
    inlined from ‘elf_find_func_offset_from_file’ at elf.c:386:2:
elf.c:60:9: warning: ‘elf_fd.fd’ may be used uninitialized [-Wmaybe-uninitialized]
   60 |         close(elf_fd->fd);
      |         ^~~~~~~~~~~~~~~~~
elf.c: In function ‘elf_find_func_offset_from_file’:
elf.c:379:23: note: ‘elf_fd.fd’ was declared here
  379 |         struct elf_fd elf_fd;
      |                       ^~~~~~
At top level:
cc1: note: unrecognized command-line option ‘-Wno-unknown-warning-option’ may have been intended to silence earlier diagnostics
[37/37] Generating scheds/rust/scx_rlfifo/scx_rlfifo with a custom command (wrapped by meson to set env)

Size diff:

Package (1)     Old Version          New Version           Net Change

scx-scheds-git  0.1.7.r0.g37dde8a-1  0.1.6.r65.g1c00de9-1   24,15 MiB

Total Installed Size:  29,68 MiB
Net Upgrade Size:      24,15 MiB

jordalgo · 2024-03-01T21:39:34Z

@ptr1337 Thanks for testing! The size increase is a little sad but I guess that's expected pulling in a submodule.

sirlucjan · 2024-03-01T21:48:47Z

@jordalgo It seems that everything is working properly.

jordalgo changed the title ~~Add libbpf as a submodule~~ Add libbpf as a submodule (take 2) Feb 29, 2024

htejun reviewed Feb 29, 2024

View reviewed changes

jordalgo force-pushed the libbpf-submodule-2 branch 3 times, most recently from 63b06fa to 494e9be Compare March 1, 2024 19:24

htejun approved these changes Mar 1, 2024

View reviewed changes

Add libbpf as a submodule

499924e

This is to potentinally reduce issues with folks using different versions of libbpf at runtime. This also: - makes static linking of libbpf the default - adds steps in `meson setup` to fetch libbpf and make it

jordalgo force-pushed the libbpf-submodule-2 branch from 494e9be to 499924e Compare March 1, 2024 20:39

sirlucjan approved these changes Mar 1, 2024

View reviewed changes

jordalgo merged commit 143743c into sched-ext:main Mar 2, 2024
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Add libbpf as a submodule (take 2) #168

Add libbpf as a submodule (take 2) #168

jordalgo commented Feb 29, 2024

jordalgo commented Feb 29, 2024

htejun Feb 29, 2024

jordalgo Feb 29, 2024

jordalgo Feb 29, 2024

htejun Feb 29, 2024

htejun Feb 29, 2024

jordalgo Mar 1, 2024 •

edited

htejun Feb 29, 2024

jordalgo Feb 29, 2024

ptr1337 commented Mar 1, 2024

jordalgo commented Mar 1, 2024

sirlucjan commented Mar 1, 2024

Add libbpf as a submodule (take 2) #168

Add libbpf as a submodule (take 2) #168

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jordalgo commented Feb 29, 2024

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jordalgo Mar 1, 2024 • edited

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ptr1337 commented Mar 1, 2024

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sirlucjan commented Mar 1, 2024

jordalgo Mar 1, 2024 •

edited