From: Masahiro Yamada <masahiroy@kernel.org>
To: David Laight <David.Laight@aculab.com>
Cc: Joe Perches <joe@perches.com>, Arnd Bergmann <arnd@arndb.de>,
Oleksandr Natalenko <oleksandr@redhat.com>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10
Date: Tue, 12 May 2020 10:10:02 +0900 [thread overview]
Message-ID: <CAK7LNAQJR5JUc37QcYS2P=WOfDQmGyAh3nJ_m8qTQDnT6LOnyA@mail.gmail.com> (raw)
In-Reply-To: <9590a4674863448e8b13fee5086fcf73@AcuMS.aculab.com>
On Sun, May 10, 2020 at 9:47 PM David Laight <David.Laight@aculab.com> wrote:
>
> From: Joe Perches
> > Sent: 08 May 2020 16:06
> > On Fri, 2020-05-08 at 13:49 +0200, Arnd Bergmann wrote:
> > > Personally, I'm more interested in improving compile speed of the kernel
> >
> > Any opinion on precompiled header support?
>
> When ever I've been anywhere near it it is always a disaster.
> It may make sense for C++ where there is lots of complicated
> code to parse in .h files. Parsing C headers is usually easier.
>
> One this I have done that significantly speeds up .h file
> processing is to take the long list of '-I directory' parameters
> that are passed to the compiler and copy the first version
> of each file into a separate 'object headers' directory.
> This saves the compiler doing lots of 'failed opens'.
>
> If each fragment makefile lists its 'public' headers make
> can generate dependency rules that do the copies.
>
> FWIW make is much faster if you delete all the builtin and
> suffix rules and rely on explicit rules for each file.
Kbuild disables Make's builtin rules at least.
# Do not use make's built-in rules and variables
# (this increases performance and avoids hard-to-debug behaviour)
MAKEFLAGS += -rR
--
Best Regards
Masahiro Yamada
next prev parent reply other threads:[~2020-05-12 1:10 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-07 22:45 [PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10 Jason A. Donenfeld
2020-05-08 8:35 ` Peter Zijlstra
2020-05-08 9:02 ` Oleksandr Natalenko
2020-05-08 11:21 ` Jason A. Donenfeld
2020-05-08 11:33 ` Oleksandr Natalenko
2020-05-08 11:49 ` Arnd Bergmann
2020-05-08 12:07 ` Jason A. Donenfeld
2020-05-08 13:04 ` Arnd Bergmann
2020-05-08 15:06 ` Joe Perches
2020-05-08 15:09 ` Arnd Bergmann
2020-05-10 12:47 ` David Laight
2020-05-10 17:45 ` Joe Perches
2020-05-10 18:58 ` David Laight
2020-05-12 1:10 ` Masahiro Yamada [this message]
2020-05-11 21:57 ` [PATCH v2] " Jason A. Donenfeld
2020-05-12 0:04 ` Linus Torvalds
2020-05-12 0:09 ` Linus Torvalds
2020-05-12 0:43 ` Jason A. Donenfeld
2020-05-12 8:44 ` Richard Biener
2020-05-13 11:27 ` [PATCH] " Artem S. Tashkinov
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='CAK7LNAQJR5JUc37QcYS2P=WOfDQmGyAh3nJ_m8qTQDnT6LOnyA@mail.gmail.com' \
--to=masahiroy@kernel.org \
--cc=David.Laight@aculab.com \
--cc=Jason@zx2c4.com \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=joe@perches.com \
--cc=linux-kernel@vger.kernel.org \
--cc=oleksandr@redhat.com \
--cc=x86@kernel.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).