[Skiboot] [PATCH] Produce XZ compressed skiboot.lid as part of build

[Michael Neuling]

On Mon, 2016-07-04 at 13:27 +1000, Stewart Smith wrote:
> With a recent HostBoot change, we can have an XZ compressed PAYLOAD
> that's automagically detected (looking at magic numbers).
> 
> This gives us three great benefits:
> 1) it's transparent, uncompressed skiboot.lid works everywhere
> 2) it lets us grow greater than 1MB binary, as long as we compress
>    down to <1MB
> 3) It speeds up boot. We currently compress down to 230kb rather than
>    922kb, which is much quicker to read off flash.
> 
> This patch produces skiboot.lid.xz alongside standard skiboot.lid.

This increases the built time quite a bit.  On my laptop a build cached in
ccache currently takes 1.0 sec.  With this patch it increases to 1.5sec, an
almost 50% increase in build time.

This is still quite fast, but can be a pain if your doing lots of builds
(say checking bisects doesn't break on a series).

I'm wondering if we could cache it somehow or avoid building it by default?

Mikey

> 
> Signed-off-by: Stewart Smith <stewart at linux.vnet.ibm.com>
> ---
>  Makefile.main | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/Makefile.main b/Makefile.main
> index 9432654e5b6c..159ce26d291a 100644
> --- a/Makefile.main
> +++ b/Makefile.main
> @@ -156,7 +156,7 @@ pflash:
>  pflash-coverity:
>  	(cd external/pflash; ./build-all-arch.sh)
>  
> -all: $(SUBDIRS) $(TARGET).lid $(TARGET).map extract-gcov
> +all: $(SUBDIRS) $(TARGET).lid $(TARGET).lid.xz $(TARGET).map extract-
> gcov
>  
>  OBJS := $(ASM) $(CORE) $(HW) $(PLATFORMS) $(LIBFDT) $(LIBFLASH)
>  ifeq ($(PORE),1)
> @@ -169,6 +169,9 @@ ALL_OBJS = $(OBJS) version.o
>  ALL_OBJS_1 = $(ALL_OBJS) asm/dummy_map.o
>  ALL_OBJS_2 = $(ALL_OBJS) asm/real_map.o
>  
> +$(TARGET).lid.xz: $(TARGET).lid
> +	$(call Q,XZ, cat $^ | xz -9 -C crc32 > $@, $@)
> +
>  $(TARGET).lid: $(TARGET).elf
>  	$(call Q,OBJCOPY, $(OBJCOPY) -O binary -S $^ $@, $@)
>