On Tue, Aug 07, 2018 at 07:30:17AM +0200, Heiko Carstens wrote: > On Mon, Aug 06, 2018 at 03:17:47PM +0200, Vasily Gorbik wrote: > > Utilize -mfentry and -mnop-mcount gcc options together with > > -mrecord-mcount to get compiler generated calls to the profiling functions > > as nops which are compatible with current -mhotpatch=0,3 approach. At the > > same time -mrecord-mcount enables __mcount_loc section generation by > > the compiler which allows to avoid using scripts/recordmcount.pl script. > > > > Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx> > > --- > > arch/s390/Kconfig | 2 ++ > > arch/s390/Makefile | 16 +++++++++------- > > arch/s390/include/asm/ftrace.h | 6 +++--- > > arch/s390/kernel/ftrace.c | 2 +- > > arch/s390/kernel/mcount.S | 2 +- > > 5 files changed, 16 insertions(+), 12 deletions(-) > > Do you have numbers which tell how much this reduces the compile time of > the kernel on s390? I assume this change makes quite some difference. > Very roughly, best time across several runs. With -j24 on 24 core lpar with -mfentry -mrecord-mcount etc real 0m54.748s user 12m32.041s sys 1m17.778s vs -mhotpatch=0,3 + scripts/recordmcount.pl: real 0m56.752s user 12m52.386s sys 1m35.873s -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
