From: Nick Desaulniers <ndesaulniers@google.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
Masahiro Yamada <masahiroy@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: Very slow clang kernel config ..
Date: Fri, 30 Apr 2021 17:23:40 -0700 [thread overview]
Message-ID: <CAKwvOdm3D=dqKw=kx46PLaiqfHOZJL3QFKGc8kxqJqpwdFFWqw@mail.gmail.com> (raw)
In-Reply-To: <CAKwvOdn3uXniVedgtpD8QFAd-hdVuVjGPa4-n0h64PTxT4XhWg@mail.gmail.com>
On Fri, Apr 30, 2021 at 5:19 PM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> A quick:
> $ perf record -e cycles:pp --call-graph lbr make LLVM=1 LLVM_IAS=1
> -j72 allmodconfig
> $ perf report --no-children --sort=dso,symbol
> shows:
> 2.35% [unknown] [k] 0xffffffffabc00fc7
> + 2.29% libc-2.31.so [.] _int_malloc
> 1.24% libc-2.31.so [.] _int_free
> + 1.23% ld-2.31.so [.] do_lookup_x
^ bfd
> + 1.14% libc-2.31.so [.] __strlen_avx2
> + 1.06% libc-2.31.so [.] malloc
> + 1.03% clang-13 [.] llvm::StringMapImpl::LookupBucketFor
> 1.01% libc-2.31.so [.] __memmove_avx_unaligned_erms
> + 0.76% conf [.] yylex
^ kconfig
> + 0.68% clang-13 [.] llvm::Instruction::getNumSuccessors
> + 0.63% libbfd-2.35.2-system.so [.] bfd_hash_lookup
^ bfd
> + 0.63% clang-13 [.] llvm::PMDataManager::findAnalysisPass
^ this is another suspect one to me, though perhaps I should isolate
out the HOSTCC invocations vs cc-option checks. Should retest with
just CC=clang rather than HOSTCC=clang set via LLVM=1.
> + 0.63% ld-2.31.so [.] _dl_lookup_symbol_x
^ bfd
> 0.62% libc-2.31.so [.] __memcmp_avx2_movbe
> 0.60% libc-2.31.so [.] __strcmp_avx2
> + 0.56% clang-13 [.] llvm::ValueHandleBase::AddToUseList
> + 0.56% clang-13 [.]
> llvm::operator==<llvm::DenseMap<llvm::BasicBlock const*, unsigned int,
> llvm::DenseMapInfo<llvm::BasicBlock const*>, llvm::detail::Dense
> 0.53% clang-13 [.]
> llvm::SmallPtrSetImplBase::insert_imp_big
--
Thanks,
~Nick Desaulniers
next prev parent reply other threads:[~2021-05-01 0:23 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-29 21:53 Very slow clang kernel config Linus Torvalds
2021-04-30 0:19 ` Nick Desaulniers
2021-04-30 2:22 ` Nick Desaulniers
2021-05-01 0:19 ` Nick Desaulniers
2021-05-01 0:23 ` Nick Desaulniers [this message]
2021-05-01 0:25 ` Nick Desaulniers
2021-05-01 0:40 ` Nick Desaulniers
2021-05-01 1:22 ` Linus Torvalds
2021-05-01 1:48 ` Nick Desaulniers
2021-05-01 2:16 ` Fangrui Song
2021-05-01 3:32 ` Tom Stellard
2021-05-01 16:32 ` Linus Torvalds
2021-05-01 19:57 ` Serge Guelton
2021-05-01 22:39 ` Linus Torvalds
2021-05-01 23:55 ` Fangrui Song
2021-05-01 21:58 ` David Laight
2021-05-02 9:31 ` Adrian Bunk
2021-05-02 11:35 ` David Laight
2021-05-02 16:12 ` Linus Torvalds
2021-05-02 16:45 ` Adrian Bunk
2021-05-02 16:49 ` Linus Torvalds
2021-05-02 17:55 ` Adrian Bunk
2021-05-02 17:59 ` Linus Torvalds
2021-05-02 21:48 ` Adrian Bunk
2021-05-04 22:02 ` Miguel Ojeda
2021-05-05 0:58 ` Theodore Ts'o
2021-05-05 17:21 ` Miguel Ojeda
2021-05-04 21:32 ` Miguel Ojeda
2021-05-05 11:05 ` David Laight
2021-05-05 13:53 ` Miguel Ojeda
2021-05-05 14:13 ` David Laight
2021-05-05 16:06 ` Miguel Ojeda
2021-05-05 16:25 ` David Laight
2021-05-05 17:55 ` Miguel Ojeda
2021-05-03 1:03 ` Maciej W. Rozycki
2021-05-03 14:38 ` Theodore Ts'o
2021-05-03 14:54 ` Theodore Ts'o
2021-05-03 17:14 ` Maciej W. Rozycki
2021-05-03 16:09 ` David Laight
2021-05-04 23:04 ` Greg Stark
2021-05-05 0:55 ` Theodore Ts'o
2021-05-01 23:37 ` Mike Hommey
2021-05-02 5:19 ` Dan Aloni
2021-05-03 16:48 ` Tom Stellard
2021-05-03 19:00 ` Fangrui Song
2021-04-30 0:52 ` Nathan Chancellor
2021-04-30 2:21 ` Nick Desaulniers
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