From: Ingo Molnar <mingo@kernel.org>
To: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Graf <tgraf@suug.ch>,
"David S. Miller" <davem@davemloft.net>,
Bart Van Assche <bvanassche@acm.org>,
Peter Zijlstra <peterz@infradead.org>,
David Rientjes <rientjes@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] force inlining of spinlock ops
Date: Tue, 12 May 2015 09:44:43 +0200 [thread overview]
Message-ID: <20150512074443.GA724@gmail.com> (raw)
In-Reply-To: <1431367042-31475-1-git-send-email-dvlasenk@redhat.com>
* Denys Vlasenko <dvlasenk@redhat.com> wrote:
> With both gcc 4.7.2 and 4.9.2, sometimes gcc mysteriously doesn't inline
> very small functions we expect to be inlined. In particular,
> with this config: http://busybox.net/~vda/kernel_config
> there are more than a thousand copies of tiny spinlock-related functions:
That's an x86-64 allyesconfig AFAICS, right?
It's not mysterious, but an effect of -Os plus allowing GCC to do
inlining heuristics:
CONFIG_CC_OPTIMIZE_FOR_SIZE=y
CONFIG_OPTIMIZE_INLINING=y
Does the problem go away if you unset of these config options?
Furtermore, what is the size win on x86 defconfig with these options
set? allyesconfig has all sorts of crazy stuff enabled while defconfig
on x86 tries to track typical distro configs.
Thanks,
Ingo
next prev parent reply other threads:[~2015-05-12 7:44 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-11 17:57 [PATCH] force inlining of spinlock ops Denys Vlasenko
2015-05-11 18:53 ` Josh Triplett
2015-05-11 22:19 ` Andrew Morton
2015-05-12 8:16 ` Hagen Paul Pfeifer
2015-05-12 9:44 ` Denys Vlasenko
2015-05-12 9:48 ` Ingo Molnar
2015-05-12 7:44 ` Ingo Molnar [this message]
2015-05-12 11:02 ` Denys Vlasenko
2015-05-12 11:43 ` Ingo Molnar
2015-05-12 13:13 ` Denys Vlasenko
2015-05-13 10:17 ` Ingo Molnar
2015-05-13 10:28 ` Denys Vlasenko
2015-05-13 10:43 ` Ingo Molnar
2015-05-13 14:09 ` Denys Vlasenko
2015-05-15 7:20 ` Heiko Carstens
-- strict thread matches above, loose matches on Subject: below --
2015-07-13 18:31 Denys Vlasenko
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