From: Doug Anderson <dianders@chromium.org>
To: Russell King <rmk+kernel@arm.linux.org.uk>,
Olof Johansson <olof@lixom.net>
Cc: Mike Frysinger <vapier@gentoo.org>,
Doug Anderson <dianders@chromium.org>,
Russell King <linux@arm.linux.org.uk>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: [PATCH] ARM: Avoid extra calls to the C compiler
Date: Tue, 25 Jun 2013 09:11:36 -0700 [thread overview]
Message-ID: <1372176696-5104-1-git-send-email-dianders@chromium.org> (raw)
Starting up the C compiler can be a slow operation on some systems.
Though these calls don't individually take a lot of time, they add up.
Rearrange the ARM Makefile a bit to avoid extra calls to the compiler
when they can be easily avoided.
When running with the Chrome OS ARM cross compiler
"armv7a-cros-linux-gnueabi-", this shaved .55 seconds (from 5.31
seconds to 4.76 seconds) off an incremental build of the kernel:
time make -j32 ARCH=arm CROSS_COMPILE=armv7a-cros-linux-gnueabi-
Thanks to Mike Frysinger for the clean trick to make this work.
Signed-off-by: Doug Anderson <dianders@chromium.org>
---
arch/arm/Makefile | 56 ++++++++++++++++++++++++++++++-------------------------
1 file changed, 31 insertions(+), 25 deletions(-)
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 1ba358b..49f0c7e 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -59,37 +59,43 @@ comma = ,
# Note that GCC does not numerically define an architecture version
# macro, but instead defines a whole series of macros which makes
# testing for a specific architecture or later rather impossible.
-arch-$(CONFIG_CPU_32v7) :=-D__LINUX_ARM_ARCH__=7 $(call cc-option,-march=armv7-a,-march=armv5t -Wa$(comma)-march=armv7-a)
-arch-$(CONFIG_CPU_32v6) :=-D__LINUX_ARM_ARCH__=6 $(call cc-option,-march=armv6,-march=armv5t -Wa$(comma)-march=armv6)
+arch-$(CONFIG_CPU_32v7) =-D__LINUX_ARM_ARCH__=7 $(call cc-option,-march=armv7-a,-march=armv5t -Wa$(comma)-march=armv7-a)
+arch-$(CONFIG_CPU_32v6) =-D__LINUX_ARM_ARCH__=6 $(call cc-option,-march=armv6,-march=armv5t -Wa$(comma)-march=armv6)
# Only override the compiler option if ARMv6. The ARMv6K extensions are
# always available in ARMv7
ifeq ($(CONFIG_CPU_32v6),y)
-arch-$(CONFIG_CPU_32v6K) :=-D__LINUX_ARM_ARCH__=6 $(call cc-option,-march=armv6k,-march=armv5t -Wa$(comma)-march=armv6k)
+arch-$(CONFIG_CPU_32v6K) =-D__LINUX_ARM_ARCH__=6 $(call cc-option,-march=armv6k,-march=armv5t -Wa$(comma)-march=armv6k)
endif
-arch-$(CONFIG_CPU_32v5) :=-D__LINUX_ARM_ARCH__=5 $(call cc-option,-march=armv5te,-march=armv4t)
-arch-$(CONFIG_CPU_32v4T) :=-D__LINUX_ARM_ARCH__=4 -march=armv4t
-arch-$(CONFIG_CPU_32v4) :=-D__LINUX_ARM_ARCH__=4 -march=armv4
-arch-$(CONFIG_CPU_32v3) :=-D__LINUX_ARM_ARCH__=3 -march=armv3
+arch-$(CONFIG_CPU_32v5) =-D__LINUX_ARM_ARCH__=5 $(call cc-option,-march=armv5te,-march=armv4t)
+arch-$(CONFIG_CPU_32v4T) =-D__LINUX_ARM_ARCH__=4 -march=armv4t
+arch-$(CONFIG_CPU_32v4) =-D__LINUX_ARM_ARCH__=4 -march=armv4
+arch-$(CONFIG_CPU_32v3) =-D__LINUX_ARM_ARCH__=3 -march=armv3
+
+# Evaluate arch cc-option calls now
+arch-y := $(arch-y)
# This selects how we optimise for the processor.
-tune-$(CONFIG_CPU_ARM7TDMI) :=-mtune=arm7tdmi
-tune-$(CONFIG_CPU_ARM720T) :=-mtune=arm7tdmi
-tune-$(CONFIG_CPU_ARM740T) :=-mtune=arm7tdmi
-tune-$(CONFIG_CPU_ARM9TDMI) :=-mtune=arm9tdmi
-tune-$(CONFIG_CPU_ARM940T) :=-mtune=arm9tdmi
-tune-$(CONFIG_CPU_ARM946E) :=$(call cc-option,-mtune=arm9e,-mtune=arm9tdmi)
-tune-$(CONFIG_CPU_ARM920T) :=-mtune=arm9tdmi
-tune-$(CONFIG_CPU_ARM922T) :=-mtune=arm9tdmi
-tune-$(CONFIG_CPU_ARM925T) :=-mtune=arm9tdmi
-tune-$(CONFIG_CPU_ARM926T) :=-mtune=arm9tdmi
-tune-$(CONFIG_CPU_FA526) :=-mtune=arm9tdmi
-tune-$(CONFIG_CPU_SA110) :=-mtune=strongarm110
-tune-$(CONFIG_CPU_SA1100) :=-mtune=strongarm1100
-tune-$(CONFIG_CPU_XSCALE) :=$(call cc-option,-mtune=xscale,-mtune=strongarm110) -Wa,-mcpu=xscale
-tune-$(CONFIG_CPU_XSC3) :=$(call cc-option,-mtune=xscale,-mtune=strongarm110) -Wa,-mcpu=xscale
-tune-$(CONFIG_CPU_FEROCEON) :=$(call cc-option,-mtune=marvell-f,-mtune=xscale)
-tune-$(CONFIG_CPU_V6) :=$(call cc-option,-mtune=arm1136j-s,-mtune=strongarm)
-tune-$(CONFIG_CPU_V6K) :=$(call cc-option,-mtune=arm1136j-s,-mtune=strongarm)
+tune-$(CONFIG_CPU_ARM7TDMI) =-mtune=arm7tdmi
+tune-$(CONFIG_CPU_ARM720T) =-mtune=arm7tdmi
+tune-$(CONFIG_CPU_ARM740T) =-mtune=arm7tdmi
+tune-$(CONFIG_CPU_ARM9TDMI) =-mtune=arm9tdmi
+tune-$(CONFIG_CPU_ARM940T) =-mtune=arm9tdmi
+tune-$(CONFIG_CPU_ARM946E) =$(call cc-option,-mtune=arm9e,-mtune=arm9tdmi)
+tune-$(CONFIG_CPU_ARM920T) =-mtune=arm9tdmi
+tune-$(CONFIG_CPU_ARM922T) =-mtune=arm9tdmi
+tune-$(CONFIG_CPU_ARM925T) =-mtune=arm9tdmi
+tune-$(CONFIG_CPU_ARM926T) =-mtune=arm9tdmi
+tune-$(CONFIG_CPU_FA526) =-mtune=arm9tdmi
+tune-$(CONFIG_CPU_SA110) =-mtune=strongarm110
+tune-$(CONFIG_CPU_SA1100) =-mtune=strongarm1100
+tune-$(CONFIG_CPU_XSCALE) =$(call cc-option,-mtune=xscale,-mtune=strongarm110) -Wa,-mcpu=xscale
+tune-$(CONFIG_CPU_XSC3) =$(call cc-option,-mtune=xscale,-mtune=strongarm110) -Wa,-mcpu=xscale
+tune-$(CONFIG_CPU_FEROCEON) =$(call cc-option,-mtune=marvell-f,-mtune=xscale)
+tune-$(CONFIG_CPU_V6) =$(call cc-option,-mtune=arm1136j-s,-mtune=strongarm)
+tune-$(CONFIG_CPU_V6K) =$(call cc-option,-mtune=arm1136j-s,-mtune=strongarm)
+
+# Evaluate tune cc-option calls now
+tune-y := $(tune-y)
ifeq ($(CONFIG_AEABI),y)
CFLAGS_ABI :=-mabi=aapcs-linux -mno-thumb-interwork
--
1.8.3
next reply other threads:[~2013-06-25 16:11 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-25 16:11 Doug Anderson [this message]
2013-06-25 16:27 ` Mike Frysinger
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