From: Kees Cook <kees@kernel.org>
To: kernel test robot <oliver.sang@intel.com>
Cc: oe-lkp@lists.linux.dev, lkp@intel.com,
linux-kernel@vger.kernel.org,
"Thomas Weißschuh" <linux@weissschuh.net>,
"Nilay Shroff" <nilay@linux.ibm.com>,
"Yury Norov" <yury.norov@gmail.com>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
linux-hardening@vger.kernel.org
Subject: Re: [linus:master] [fortify] 239d87327d: vm-scalability.throughput 17.3% improvement
Date: Thu, 9 Jan 2025 12:38:04 -0800 [thread overview]
Message-ID: <202501091236.E3EDA2188@keescook> (raw)
In-Reply-To: <202501090850.F23EBEBC5B@keescook>
On Thu, Jan 09, 2025 at 08:51:44AM -0800, Kees Cook wrote:
> On Thu, Jan 09, 2025 at 02:57:58PM +0800, kernel test robot wrote:
> > kernel test robot noticed a 17.3% improvement of vm-scalability.throughput on:
> >
> > commit: 239d87327dcd361b0098038995f8908f3296864f ("fortify: Hide run-time copy size from value range tracking")
> > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
>
> Well that is unexpected. There should be no binary output difference
> with that patch. I will investigate...
It looks like hiding the size value from GCC has the side-effect of
breaking memcpy inlining in many places. I would expect this to make
things _slower_, though. O_o
--
Kees Cook
next prev parent reply other threads:[~2025-01-09 20:38 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-09 6:57 [linus:master] [fortify] 239d87327d: vm-scalability.throughput 17.3% improvement kernel test robot
2025-01-09 16:51 ` Kees Cook
2025-01-09 20:38 ` Kees Cook [this message]
2025-01-09 20:52 ` Mateusz Guzik
2025-01-09 21:12 ` Kees Cook
2025-01-09 22:01 ` Mateusz Guzik
2025-01-10 16:58 ` Kees Cook
2025-01-10 19:14 ` Mateusz Guzik
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=202501091236.E3EDA2188@keescook \
--to=kees@kernel.org \
--cc=gregkh@linuxfoundation.org \
--cc=linux-hardening@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@weissschuh.net \
--cc=lkp@intel.com \
--cc=nilay@linux.ibm.com \
--cc=oe-lkp@lists.linux.dev \
--cc=oliver.sang@intel.com \
--cc=yury.norov@gmail.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.