On Aug 21, 2013, at 10:45 PM, sun york-R58495 wrote:
On Aug 21, 2013, at 10:02 PM, Marek Vasut wrote:
Dear sun york-R58495,
On Aug 21, 2013, at 7:51 PM, Marek Vasut wrote:
Dear York Sun,
On 05/20/2013 10:25 AM, Marek Vasut wrote:
Prefix HOSTCC and CC with CCACHE variable to allow easy use of ccache. In case the user wants to use ccache, exporting CCACHE=ccache will do the trick. It is of course possible to either make the cross-compiler name into a shellscript which invokes the ccache and the compiler, but setting this variable makes use of ccache easier and more convenient.
Using ccache becomes convenient when using MAKEALL for large build tests, where the speedup after building the cache for the first time is about 4-6 times.
Signed-off-by: Marek Vasut marex@denx.de Cc: Tom Rini trini@ti.com
config.mk | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/config.mk b/config.mk index 1fd109f..d59ded2 100644 --- a/config.mk +++ b/config.mk @@ -98,6 +98,8 @@ else
HOSTCC = gcc endif
+HOSTCC := $(CCACHE) $(HOSTCC)
ifeq ($(HOSTOS),cygwin) HOSTCFLAGS += -ansi endif
@@ -140,13 +142,13 @@ binutils-version = $(shell $(SHELL) $(SRCTREE)/tools/binutils-version.sh $(AS))
# # Include the make variables (CC, etc...) #
-AS = $(CROSS_COMPILE)as +AS = $(CCACHE) $(CROSS_COMPILE)as
# Always use GNU ld LD = $(shell if $(CROSS_COMPILE)ld.bfd -v > /dev/null 2>&1; \
then echo "$(CROSS_COMPILE)ld.bfd"; else echo"$(CROSS_COMPILE)ld";
fi;)-CC = $(CROSS_COMPILE)gcc +CC = $(CCACHE) $(CROSS_COMPILE)gcc
CPP = $(CC) -E AR = $(CROSS_COMPILE)ar NM = $(CROSS_COMPILE)nm
@@ -320,7 +322,7 @@ endif
####################################################################### # #
-export HOSTCC HOSTCFLAGS HOSTLDFLAGS PEDCFLAGS HOSTSTRIP CROSS_COMPILE
\
+export HOSTCC HOSTCFLAGS HOSTLDFLAGS PEDCFLAGS HOSTSTRIP CROSS_COMPILE CCACHE \
AS LD CC CPP AR NM STRIP OBJCOPY OBJDUMP MAKE
export CONFIG_SYS_TEXT_BASE PLATFORM_CPPFLAGS PLATFORM_RELFLAGS
CPPFLAGS
CFLAGS AFLAGS
Where did this patch go? I found it useful.
It needs additional fixes, try running with MAKEALL and you will see the problem -- the problem is you would need separate ccache for each MAKEALL thread.
I didn't use this patch but I modified config.mk as this patch did. MAKEALL works fine for "-a powerpc". It cuts my compiling time more than half for 660+ boards.
That is still poor, it should be much faster. If you use separate ccache for each board, then it will be _much_ more performant.
The problem is that when rebuilding all of those 680 configurations, the cached files get replaced by ones based on different board config all the time => you need to rebuild them => you loose performance.
I kind of get it. I have to increase my ccache size a lot (more than 2GB) to get consistent cache hit. I thought that was because I was using out-of-tree build when setting BUILD_NBUILDS. For the first time I run MAKEALL with ccache, it was completely miss. I mean zero hit. It would be nice to be able hit the cache. I was read the ccache document to understand how the path is involved when calculating the hash. How do you plan to make it work?
I forgot to mention, if the ccache size is at default (1GB), I don't see any performance improvement by using ccache. I think that's what you meant the cached files get replaced. I don't understand what you mean to use separated ccache for each board. Would it be equivalent to have a big cache? I was compiling with and without BUILD_NBUILDS, and my cache size is more than 3GB now. I could see the improvement by 2x~3x faster, but not more.
York