From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Christophe Leroy <christophe.leroy@c-s.fr>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: powerpc/Makefile: set -mcpu=860 flag for the 8xx
Date: Tue, 5 Jun 2018 00:11:07 +1000 (AEST) [thread overview]
Message-ID: <40zxgL3MdHz9s7X@ozlabs.org> (raw)
In-Reply-To: <20180528060834.72DE86F377@po14934vm.idsi0.si.c-s.fr>
On Mon, 2018-05-28 at 06:08:34 UTC, Christophe Leroy wrote:
> When compiled with GCC 8.1, vmlinux is significantly bigger than
> with GCC 4.8.
>
> When looking at the generated code with objdump, we notice that
> all functions and loops when a 16 bytes alignment. This significantly
> increases the size of the kernel. It is pointless and even
> counterproductive as on the 8xx 'nop' also consumes one clock cycle.
>
> Size of vmlinux with GCC 4.8:
> text data bss dec hex filename
> 5801948 1626076 457796 7885820 7853fc vmlinux
>
> Size of vmlinux with GCC 8.1:
> text data bss dec hex filename
> 6764592 1630652 456476 8851720 871108 vmlinux
>
> Size of vmlinux with GCC 8.1 and this patch:
> text data bss dec hex filename
> 6331544 1631756 456476 8419776 8079c0 vmlinux
>
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/1c38976334c0efce1b285369a6037f
cheers
prev parent reply other threads:[~2018-06-04 14:11 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-28 6:08 [PATCH] powerpc/Makefile: set -mcpu=860 flag for the 8xx Christophe Leroy
2018-06-04 14:11 ` Michael Ellerman [this message]
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=40zxgL3MdHz9s7X@ozlabs.org \
--to=patch-notifications@ellerman.id.au \
--cc=benh@kernel.crashing.org \
--cc=christophe.leroy@c-s.fr \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=paulus@samba.org \
/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).