Hi Masahiro, On 18 February 2014 01:02, Masahiro Yamada <yamad...@jp.panasonic.com> wrote: > Hello Simon, > > >> >> I'm not sure whether to start a new thread or not, but here in one >> observations which might be useful. >> >> With current master, a 'null' build (with nothing changed) takes about >> 5s for me. >> >> time >> CROSS_COMPILE=/opt/linaro/gcc-linaro-arm-linux-gnueabihf-4.8-2013.08_linux/bin/arm >> -linux-gnueabihf- ARCH=arm make -j1 >> real 0m4.978s >> user 0m1.144s >> sys 0m0.360s >> >> >> With the kbuild series, it takes a lot longer: >> >> real 0m46.600s >> user 0m17.628s >> sys 0m8.664s > > Thanks for your feedback. > > Hmm, Kbuild is 9 times slower on your computer. > This is a big difference. (It was about 1.6 x slower on my box.) > > I don't know where such a difference came from.
Note this is a 32-core machine. > >> There seem to be noticeable pauses between things happening. I'm not >> quite sure how to dig into it more. Is it possible that cc-option is >> no-longer caching the various compiler options? > > I guess it's possible. > > Is sandbox build slow as well? > Sandbox has no cc-option. > If cc-option is the cause of pauses, sandbox build > should be faster. Yes actually sandbox is pretty fast. > > Anyway, evaluating cc-option multiple times isn't nice > and its optimization is on my TODO list. > > Historically, U-Boot has included all > config.mk (arch/*/config.mk and board/*/config.mk) > every time descending into subdirectories. > That means cc-options are evaluated over and over again. > Caching cc-option is one of work arounds, but we should not > revive it. > > What we should do is to include arch/*/config.mk and board/*/config.mk > only once at the top Makefile and export options. That sounds good to me. Thanks for looking at it. Regards, Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot