From: Bill Wendling <morbo@google.com>
To: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>,
Masahiro Yamada <masahiroy@kernel.org>,
Linux Doc Mailing List <linux-doc@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
Clang-Built-Linux ML <clang-built-linux@googlegroups.com>,
Andrew Morton <akpm@linux-foundation.org>,
Nathan Chancellor <natechancellor@gmail.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Sami Tolvanen <samitolvanen@google.com>,
Fangrui Song <maskray@google.com>
Subject: Re: [PATCH v5] pgo: add clang's Profile Guided Optimization infrastructure
Date: Mon, 18 Jan 2021 13:56:39 -0800 [thread overview]
Message-ID: <CAGG=3QUcaY1wzJhBD4ZGhPSNPik-kL0PuoE1SJqkFJEM_mkGYA@mail.gmail.com> (raw)
In-Reply-To: <CA+icZUXa9wvSWe=21_gjAapoHpbgBmYzFpQjb=o_WRQgK+O4gA@mail.gmail.com>
On Mon, Jan 18, 2021 at 9:26 AM Sedat Dilek <sedat.dilek@gmail.com> wrote:
>
> On Mon, Jan 18, 2021 at 1:39 PM Sedat Dilek <sedat.dilek@gmail.com> wrote:
> >
> > On Mon, Jan 18, 2021 at 3:32 AM Bill Wendling <morbo@google.com> wrote:
> > >
> > > On Sun, Jan 17, 2021 at 4:27 PM Sedat Dilek <sedat.dilek@gmail.com> wrote:
> > > >
> > > > [ big snip ]
> > >
> > > [More snippage.]
> > >
> > > > [ CC Fangrui ]
> > > >
> > > > With the attached...
> > > >
> > > > [PATCH v3] module: Ignore _GLOBAL_OFFSET_TABLE_ when warning for
> > > > undefined symbols
> > > >
> > > > ...I was finally able to boot into a rebuild PGO-optimized Linux-kernel.
> > > > For details see ClangBuiltLinux issue #1250 "Unknown symbol
> > > > _GLOBAL_OFFSET_TABLE_ loading kernel modules".
> > > >
> > > Thanks for confirming that this works with the above patch.
> > >
> > > > @ Bill Nick Sami Nathan
> > > >
> > > > 1, Can you say something of the impact passing "LLVM_IAS=1" to make?
> > >
> > > The integrated assembler and this option are more-or-less orthogonal
> > > to each other. One can still use the GNU assembler with PGO. If you're
> > > having an issue, it may be related to ClangBuiltLinux issue #1250.
> > >
> > > > 2. Can you please try Nick's DWARF v5 support patchset v5 and
> > > > CONFIG_DEBUG_INFO_DWARF5=y (see attachments)?
> > > >
> > > I know Nick did several tests with PGO. He may have looked into it
> > > already, but we can check.
> > >
> >
> > Reproducible.
> >
> > LLVM_IAS=1 + DWARF5 = Not bootable
> >
> > I will try:
> >
> > LLVM_IAS=1 + DWARF4
> >
>
> I was not able to boot into such a built Linux-kernel.
>
PGO will have no effect on debugging data. If this is an issue with
DWARF, then it's likely orthogonal to the PGO patch.
> For me worked: DWARF2 and LLVM_IAS=1 *not* set.
>
> Of course, this could be an issue with my system's LLVM/Clang.
>
> Debian clang version
> 12.0.0-++20210115111113+45ef053bd709-1~exp1~20210115101809.3724
>
Please use the official clang 11.0.1 release
(https://releases.llvm.org/download.html), modifying the
kernel/pgo/Kconfig as I suggested above. The reason we specify clang
12 for the minimal version is because of an issue that was recently
fixed.
> Can you give me a LLVM commit-id where you had success with LLVM_IAS=1
> and especially CONFIG_DEBUG_INFO_DWARF5=y?
> Success means I was able to boot in QEMU and/or bare metal.
>
The DWARF5 patch isn't in yet, so I don't want to rely upon it too much.
-bw
next prev parent reply other threads:[~2021-01-18 21:57 UTC|newest]
Thread overview: 116+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-11 8:18 [PATCH] pgo: add clang's Profile Guided Optimization infrastructure Bill Wendling
2021-01-11 8:39 ` Sedat Dilek
2021-01-11 8:42 ` Sedat Dilek
2021-01-11 9:17 ` Bill Wendling
2021-01-11 9:57 ` Sedat Dilek
2021-01-11 18:28 ` Nathan Chancellor
2021-01-11 20:12 ` Fangrui Song
2021-01-11 20:23 ` Bill Wendling
2021-01-11 20:31 ` Fangrui Song
2021-01-12 0:37 ` Bill Wendling
2021-01-12 0:44 ` Fāng-ruì Sòng
2021-01-11 21:04 ` Nathan Chancellor
2021-01-11 21:17 ` Nick Desaulniers
2021-01-11 21:32 ` Bill Wendling
2021-01-12 5:14 ` [PATCH v2] " Bill Wendling
2021-01-12 5:17 ` Sedat Dilek
2021-01-12 5:31 ` [PATCH v3] " Bill Wendling
[not found] ` <202101121755.pyYoRozB-lkp@intel.com>
2021-01-12 17:22 ` Nathan Chancellor
2021-01-13 6:19 ` [PATCH v4] " Bill Wendling
2021-01-13 20:55 ` Nathan Chancellor
2021-01-13 21:59 ` Bill Wendling
2021-01-14 4:07 ` Nick Desaulniers
2021-01-16 0:01 ` Nick Desaulniers
2021-01-16 0:13 ` Nick Desaulniers
2021-01-16 4:30 ` Sedat Dilek
2021-01-16 5:07 ` Sedat Dilek
2021-01-16 5:18 ` Sedat Dilek
2021-01-18 0:57 ` Sedat Dilek
2021-01-13 23:01 ` Nick Desaulniers
2021-01-16 9:43 ` [PATCH v5] " Bill Wendling
2021-01-16 17:38 ` Sedat Dilek
2021-01-16 18:36 ` Sedat Dilek
2021-01-16 20:23 ` Bill Wendling
2021-01-17 10:44 ` Sedat Dilek
2021-01-17 10:53 ` Sedat Dilek
2021-01-17 11:23 ` Sedat Dilek
2021-01-17 11:42 ` Sedat Dilek
2021-01-17 11:58 ` Sedat Dilek
[not found] ` <CA+icZUXmn15w=kSq2CZzQD5JggJw_9AEam=Sz13M0KpJ68MWZg@mail.gmail.com>
2021-01-17 17:42 ` Sedat Dilek
2021-01-17 20:34 ` Bill Wendling
[not found] ` <CA+icZUU1HihUFaEHzF69+01+Picg8aq6HAqHupxiRqyDGJ=Mpw@mail.gmail.com>
[not found] ` <CA+icZUUuzA5JEXyVzKbVX+T3xeOdRAU6-mntbo+VwwTxqmN7LA@mail.gmail.com>
2021-01-18 2:32 ` Bill Wendling
2021-01-18 12:39 ` Sedat Dilek
2021-01-18 17:26 ` Sedat Dilek
2021-01-18 21:56 ` Bill Wendling [this message]
2021-01-18 23:29 ` Sedat Dilek
2021-01-21 2:03 ` Sedat Dilek
2021-01-21 22:44 ` Sedat Dilek
2021-01-22 1:42 ` Nick Desaulniers
2021-01-22 1:49 ` Sedat Dilek
2021-01-22 1:52 ` Nick Desaulniers
2021-01-20 1:02 ` Nick Desaulniers
2021-01-21 0:51 ` Nick Desaulniers
2021-01-21 8:24 ` Bill Wendling
2021-01-21 8:24 ` [PATCH v6] " Bill Wendling
2021-01-21 10:34 ` Sedat Dilek
2021-01-22 1:44 ` Nick Desaulniers
2021-01-22 1:51 ` Sedat Dilek
2021-01-22 0:14 ` Sedat Dilek
2021-01-22 0:58 ` Sedat Dilek
2021-01-22 1:29 ` Nick Desaulniers
2021-01-22 10:11 ` [PATCH v7] " Bill Wendling
2021-01-22 11:31 ` Sedat Dilek
2021-01-22 18:41 ` Nick Desaulniers
[not found] ` <CA+icZUU=XfwqMcXYonQKcD4QgqTBW-mA+d_84b7cU2R3HYPOSQ@mail.gmail.com>
2021-01-28 21:12 ` Nick Desaulniers
2021-01-28 21:19 ` Sedat Dilek
2021-01-28 21:24 ` Nick Desaulniers
2021-01-28 21:39 ` Sedat Dilek
2021-01-29 7:43 ` Sedat Dilek
2021-01-29 21:48 ` Nick Desaulniers
2021-02-10 23:25 ` Bill Wendling
2021-02-22 21:52 ` Bill Wendling
2021-02-26 22:20 ` [PATCH v8] " Bill Wendling
2021-02-26 22:55 ` Bill Wendling
2021-02-28 18:52 ` Fangrui Song
2021-02-28 21:50 ` Fangrui Song
2021-01-12 17:37 ` [PATCH v2] " Nick Desaulniers
2021-01-12 17:45 ` Fāng-ruì Sòng
2021-01-21 2:21 ` [PATCH] " Sedat Dilek
2021-01-22 1:34 ` Nick Desaulniers
2021-01-22 1:43 ` Sedat Dilek
2021-04-07 21:17 ` [PATCH v9] " Bill Wendling
2021-04-07 21:22 ` Kees Cook
2021-04-07 21:44 ` Fāng-ruì Sòng
2021-04-07 21:47 ` Nathan Chancellor
2021-04-07 21:58 ` Bill Wendling
2021-05-19 21:37 ` Kees Cook
2021-05-22 23:51 ` Bill Wendling
2021-05-31 21:12 ` Nathan Chancellor
2021-06-01 17:31 ` Nick Desaulniers
2021-06-12 16:59 ` Peter Zijlstra
2021-06-12 17:25 ` Bill Wendling
2021-06-12 18:15 ` Peter Zijlstra
2021-06-12 19:10 ` Bill Wendling
2021-06-12 19:28 ` Bill Wendling
2021-06-12 20:25 ` Peter Zijlstra
2021-06-12 20:56 ` Bill Wendling
2021-06-12 22:47 ` Bill Wendling
2021-06-13 18:07 ` Bill Wendling
2021-06-14 9:43 ` Peter Zijlstra
2021-06-14 10:18 ` Peter Zijlstra
2021-06-14 7:51 ` Peter Zijlstra
2021-06-14 9:01 ` Peter Zijlstra
2021-06-14 9:39 ` Bill Wendling
2021-06-14 10:44 ` Peter Zijlstra
2021-06-14 11:41 ` Bill Wendling
2021-06-14 11:43 ` Bill Wendling
2021-06-14 14:16 ` Marco Elver
2021-06-14 15:26 ` Kees Cook
2021-06-14 15:35 ` Peter Zijlstra
2021-06-14 16:22 ` Kees Cook
2021-06-14 18:07 ` Nick Desaulniers
2021-06-14 20:49 ` Nick Desaulniers
2021-06-14 15:46 ` Peter Zijlstra
2021-06-14 16:03 ` Nick Desaulniers
2021-06-12 20:20 ` Fangrui Song
2021-06-12 20:31 ` Peter Zijlstra
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