Re: ANNOUNCE: pahole v1.24 (Faster BTF encoding, 64-bit BTF enum entries)

From: Luna Jernberg <droidbittin@gmail.com>
To: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>, droidbittin@gmail.com
Cc: dwarves@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Alibek Omarov <a1ba.omarov@gmail.com>,
	Kornilios Kourtis <kornilios@isovalent.com>,
	Kui-Feng Lee <kuifeng@fb.com>, Yonghong Song <yhs@fb.com>,
	bpf@vger.kernel.org, Jiri Olsa <jolsa@kernel.org>
Subject: Re: ANNOUNCE: pahole v1.24 (Faster BTF encoding, 64-bit BTF enum entries)
Date: Wed, 24 Aug 2022 16:38:47 +0200	[thread overview]
Message-ID: <CADo9pHhcw2+WEYfD=hJ-o67fw9Uf+ERS8xo2SHApNQgPwGCmBA@mail.gmail.com> (raw)
In-Reply-To: <YwY3qEa2gFsPg2jz@kernel.org>

https://forum.endeavouros.com/t/failed-to-start-load-kernel-modules-on-boot-after-system-update-nvidia/30584/17?u=sradjoker

On 8/24/22, Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com> wrote:
> Em Wed, Aug 24, 2022 at 04:36:18PM +0200, Luna Jernberg escreveu:
>> The Nvidia driver breaks
>
> How? What are the messages?
>
> Here is a test on an Archlinux container:
>
> [perfbuilder@758097c04011 dwarves-1.24]$ pahole --version
> v1.24
> [perfbuilder@758097c04011 dwarves-1.24]$ cat /etc/os-release
> NAME="Arch Linux"
> PRETTY_NAME="Arch Linux"
> ID=arch
> BUILD_ID=rolling
> VERSION_ID=TEMPLATE_VERSION_ID
> ANSI_COLOR="38;2;23;147;209"
> HOME_URL="https://archlinux.org/"
> DOCUMENTATION_URL="https://wiki.archlinux.org/"
> SUPPORT_URL="https://bbs.archlinux.org/"
> BUG_REPORT_URL="https://bugs.archlinux.org/"
> LOGO=archlinux-logo
> [perfbuilder@758097c04011 dwarves-1.24]$ pahole list_head
> struct list_head {
> 	struct list_head *         next;                 /*     0     8 */
> 	struct list_head *         prev;                 /*     8     8 */
>
> 	/* size: 16, cachelines: 1, members: 2 */
> 	/* last cacheline: 16 bytes */
> };
> [perfbuilder@758097c04011 dwarves-1.24]$ pahole --sizes | sort -k2 -nr |
> head
> rcu_state	300608	7
> cmp_data	290904	1
> dec_data	274520	1
> cpu_entry_area	241664	0
> kvm	190016	6
> pglist_data	173440	6
> ZSTD_DCtx_s	161480	6
> saved_cmdlines_buffer	131104	1
> debug_store_buffers	131072	0
> hid_parser	110848	1
> [perfbuilder@758097c04011 dwarves-1.24]$
>
>> On 8/24/22, Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com> wrote:
>> > Em Wed, Aug 24, 2022 at 03:23:29PM +0200, Luna Jernberg escreveu:
>> >> This package breaks on Arch Linux at the moment and if you are using
>> >> Arch
>> >> its recommended that you downgrade to 1.23
>> >
>> > Breaks in what sense? Can you please provide details?
>> >
>> > - Arnaldo
>> >
>> >> On Tue, Aug 23, 2022 at 1:59 AM Arnaldo Carvalho de Melo
>> >> <acme@kernel.org>
>> >> wrote:
>> >>
>> >> > Hi,
>> >> >
>> >> >         The v1.24 release of pahole and its friends is out, with
>> >> > faster
>> >> > BTF generation by parallelizing the encoding part in addition to the
>> >> > previoulsy parallelized DWARF loading, support for 64-bit BTF
>> >> > enumeration
>> >> > entries, signed BTF encoding of 'char', exclude/select DWARF loading
>> >> > based on the language that generated the objects, etc.
>> >> >
>> >> > Main git repo:
>> >> >
>> >> >    git://git.kernel.org/pub/scm/devel/pahole/pahole.git
>> >> >
>> >> > Mirror git repo:
>> >> >
>> >> >    https://github.com/acmel/dwarves.git
>> >> >
>> >> > tarball + gpg signature:
>> >> >
>> >> >    https://fedorapeople.org/~acme/dwarves/dwarves-1.24.tar.xz
>> >> >    https://fedorapeople.org/~acme/dwarves/dwarves-1.24.tar.bz2
>> >> >    https://fedorapeople.org/~acme/dwarves/dwarves-1.24.tar.sign
>> >> >
>> >> >         Thanks a lot to all the contributors and distro packagers,
>> >> > you're
>> >> > on the
>> >> > CC list, I appreciate a lot the work you put into these tools,
>> >> >
>> >> > Best Regards,
>> >> >
>> >> > BTF encoder:
>> >> >
>> >> > - Add support to BTF_KIND_ENUM64 to represent enumeration entries
>> >> > with
>> >> >   more than 32 bits.
>> >> >
>> >> > - Support multithreaded encoding, in addition to DWARF multithreaded
>> >> >   loading, speeding up the process.
>> >> >
>> >> >   Selected just like DWARF multithreaded loading, using the 'pahole
>> >> > -j'
>> >> >   option.
>> >> >
>> >> > - Encode 'char' type as signed.
>> >> >
>> >> > BTF Loader:
>> >> >
>> >> > - Add support to BTF_KIND_ENUM64.
>> >> >
>> >> > pahole:
>> >> >
>> >> > - Introduce --lang and --lang_exclude to specify the language the
>> >> >   DWARF compile units were originated from to use or filter.
>> >> >
>> >> >   Use case is to exclude Rust compile units while aspects of the
>> >> >   DWARF generated for it get sorted out in a way that the kernel
>> >> >   BPF verifier don't refuse loading the BTF generated from them.
>> >> >
>> >> > - Introduce --compile to generate compilable code in a similar
>> >> > fashion
>> >> > to:
>> >> >
>> >> >    bpftool btf dump file vmlinux format c > vmlinux.h
>> >> >
>> >> >   As with 'bpftool', this will notice type shadowing, i.e. multiple
>> >> > types
>> >> >   with the same name and will disambiguate by adding a suffix.
>> >> >
>> >> > - Don't segfault when processing bogus files.
>> >> >
>> >
>> > --
>> >
>> > - Arnaldo
>> >
>
> --
>
> - Arnaldo
>