From: Yang Shi <shy828301@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Rik van Riel <riel@surriel.com>,
Thorsten Leemhuis <regressions@leemhuis.info>,
"Huang, Ying" <ying.huang@intel.com>,
kernel test robot <yujie.liu@intel.com>,
lkp@lists.01.org, lkp@intel.com,
Matthew Wilcox <willy@infradead.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
feng.tang@intel.com, zhengjun.xing@linux.intel.com,
fengwei.yin@intel.com, Nathan Chancellor <nathan@kernel.org>
Subject: Re: [mm] f35b5d7d67: will-it-scale.per_process_ops -95.5% regression
Date: Thu, 1 Dec 2022 13:44:57 -0800 [thread overview]
Message-ID: <CAHbLzkpH3StOAP3jnR1ALO9dpz43j8zOR88+fj4iwCRYsnt3=A@mail.gmail.com> (raw)
In-Reply-To: <20221201132237.c55c4bd07ba44463b146882e@linux-foundation.org>
On Thu, Dec 1, 2022 at 1:22 PM Andrew Morton <akpm@linux-foundation.org> wrote:
>
> On Thu, 01 Dec 2022 15:29:41 -0500 Rik van Riel <riel@surriel.com> wrote:
>
> > On Thu, 2022-12-01 at 19:33 +0100, Thorsten Leemhuis wrote:
> > > Hi, this is your Linux kernel regression tracker.
> > >
> > > On 28.11.22 07:40, Nathan Chancellor wrote:
> > > > Hi Rik,
> > >
> > > I wonder what we should do about below performance regression. Is
> > > reverting the culprit now and reapplying it later together with a fix
> > > a
> > > viable option? Or was anything done/is anybody doing something
> > > already
> > > to address the problem and I just missed it?
> >
> > The changeset in question speeds up kernel compiles with
> > GCC, as well as the runtime speed of other programs, due
> > to being able to use THPs more. However, it slows down kernel
> > compiles with clang, due to ... something clang does.
> >
> > I have not figured out what that something is yet.
> >
> > I don't know if I have the wrong version of clang here,
> > but I have not seen any smoking gun at all when tracing
> > clang system calls. I see predominantly small mmap and
> > unmap calls, and nothing that even triggers 2MB alignment.
>
> 2.8% speedup for gcc is nice. Massive slowdown in the malloc banchmark
> and in LLVM/clang is very bad - we don't know what other userspace will
> be so affected.
>
> So I think we revert until this is fully understood.
+1
>
>
next prev parent reply other threads:[~2022-12-01 21:45 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-18 8:44 [mm] f35b5d7d67: will-it-scale.per_process_ops -95.5% regression kernel test robot
2022-10-19 2:05 ` Huang, Ying
2022-10-20 4:23 ` Nathan Chancellor
2022-10-20 5:07 ` Huang, Ying
2022-10-20 15:28 ` Rik van Riel
2022-10-20 17:16 ` Nathan Chancellor
2022-11-28 6:40 ` Nathan Chancellor
2022-12-01 18:33 ` Thorsten Leemhuis
2022-12-01 20:29 ` Rik van Riel
2022-12-01 21:22 ` Andrew Morton
2022-12-01 21:44 ` Yang Shi [this message]
2022-12-02 8:46 ` Thorsten Leemhuis
2022-12-02 18:44 ` Andrew Morton
2022-12-02 19:37 ` Thorsten Leemhuis
2022-12-01 21:35 ` Nathan Chancellor
2022-12-16 11:48 ` Yin, Fengwei
2022-10-20 16:40 ` Yujie Liu
2022-11-29 8:59 ` [mm] f35b5d7d67: will-it-scale.per_process_ops -95.5% regression #forregzbot Thorsten Leemhuis
2022-12-02 6:43 ` Thorsten Leemhuis
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAHbLzkpH3StOAP3jnR1ALO9dpz43j8zOR88+fj4iwCRYsnt3=A@mail.gmail.com' \
--to=shy828301@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=feng.tang@intel.com \
--cc=fengwei.yin@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=lkp@intel.com \
--cc=lkp@lists.01.org \
--cc=nathan@kernel.org \
--cc=regressions@leemhuis.info \
--cc=riel@surriel.com \
--cc=willy@infradead.org \
--cc=ying.huang@intel.com \
--cc=yujie.liu@intel.com \
--cc=zhengjun.xing@linux.intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).