Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <CAHk-=wjmNOoX8iPtYsM8PVa+7DE1=5bv-XVe_egP0ZOiuT=7CQ@mail.gmail.com>
 <CAKwvOdmMF_v9TzBtFn2S1qSS_yCDO8D-u3WhBehUM7gzjcdjUQ@mail.gmail.com>
 <CAKwvOdk+V2dc31guafFM=N2ez4SrwCmah+mimUG3MzPMx_2efQ@mail.gmail.com>
 <CAKwvOdn3uXniVedgtpD8QFAd-hdVuVjGPa4-n0h64PTxT4XhWg@mail.gmail.com> <CAKwvOdm3D=dqKw=kx46PLaiqfHOZJL3QFKGc8kxqJqpwdFFWqw@mail.gmail.com>
In-Reply-To: <CAKwvOdm3D=dqKw=kx46PLaiqfHOZJL3QFKGc8kxqJqpwdFFWqw@mail.gmail.com>
From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Fri, 30 Apr 2021 17:25:02 -0700
Message-ID: <CAKwvOdkp_P8BCtFuKqDrtC_=A89ZfDf66Yr3FL2e=ojwv4KaMA@mail.gmail.com>
Subject: Re: Very slow clang kernel config ..
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>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Fri, Apr 30, 2021 at 5:23 PM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> 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


> > +    0.63%  ld-2.31.so               [.] _dl_lookup_symbol_x
>
> ^ bfd

Ah, no, sorry, these are the runtime link editor/loader. So probably
spending quite some time resolving symbols in large binaries.

-- 
Thanks,
~Nick Desaulniers