Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756711AbaDXMI0 (ORCPT ); Thu, 24 Apr 2014 08:08:26 -0400 Received: from top.free-electrons.com ([176.31.233.9]:37463 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753318AbaDXMHr (ORCPT ); Thu, 24 Apr 2014 08:07:47 -0400 From: Michael Opdenacker To: akpm@linux-foundation.org Cc: paulmck@linux.vnet.ibm.com, fweisbec@gmail.com, josh@joshtriplett.org, eparis@redhat.com, paul.gortmaker@windriver.com, vapier@gentoo.org, kyungsik.lee@lge.com, jslaby@suse.cz, dwight.engen@oracle.com, pefoley2@pefoley.com, linux-kernel@vger.kernel.org, Michael Opdenacker Subject: [PATCH 1/1] init/Kconfig: improve CC_OPTIMIZE_FOR_SIZE documentation Date: Thu, 24 Apr 2014 14:07:34 +0200 Message-Id: <1398341254-4626-2-git-send-email-michael.opdenacker@free-electrons.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1398341254-4626-1-git-send-email-michael.opdenacker@free-electrons.com> References: <1398341254-4626-1-git-send-email-michael.opdenacker@free-electrons.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Signed-off-by: Michael Opdenacker --- init/Kconfig | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/init/Kconfig b/init/Kconfig index 9d3585bb2a7a..b6394a9ddc38 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1251,7 +1251,19 @@ config CC_OPTIMIZE_FOR_SIZE bool "Optimize for size" help Enabling this option will pass "-Os" instead of "-O2" to gcc - resulting in a smaller kernel. + resulting in a smaller but slower kernel. + + This option can be useful in very small systems where every + byte counts. + + A smaller kernel will also be slightly faster to load and start. + However, experiments have shown that such early speedups are + quickly offset by the slower kernel speed. Unless you are running + a very simple user space, the total boot time should be degraded + by this option. + + Anyway, kernel code will be slower to execute and overall system + performance will be degraded. If unsure, say N. -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/