configure: fix performance regression due to PIC objects
authorPaolo Bonzini <pbonzini@redhat.com>
Wed, 7 Oct 2020 16:00:17 +0000 (17:00 +0100)
committerAlex Bennée <alex.bennee@linaro.org>
Fri, 9 Oct 2020 16:27:50 +0000 (17:27 +0100)
Because most files in QEMU are grouped into static libraries, Meson conservatively
compiles them with -fPIC.  This is overkill and produces slowdowns up to 20% on
some TCG tests.

As a stopgap measure, use the b_staticpic option to limit the slowdown to
--enable-pie.  https://github.com/mesonbuild/meson/pull/7760 will allow
us to use b_staticpic=false and let Meson do the right thing.

Reported-by: Ahmed Karaman <ahmedkrmn@outlook.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200924092314.1722645-57-pbonzini@redhat.com>
Message-Id: <20201007160038.26953-2-alex.bennee@linaro.org>

configure

index 28df227db56605ce8f721d6adeda934e96dc2db4..b553288c5e44f7c25c4686f2617837f0ae7ab752 100755 (executable)
--- a/configure
+++ b/configure
@@ -7209,6 +7209,7 @@ NINJA=${ninja:-$PWD/ninjatool} $meson setup \
         -Dwerror=$(if test "$werror" = yes; then echo true; else echo false; fi) \
         -Dstrip=$(if test "$strip_opt" = yes; then echo true; else echo false; fi) \
         -Db_pie=$(if test "$pie" = yes; then echo true; else echo false; fi) \
+        -Db_staticpic=$(if test "$pie" = yes; then echo true; else echo false; fi) \
         -Db_coverage=$(if test "$gcov" = yes; then echo true; else echo false; fi) \
        -Dmalloc=$malloc -Dmalloc_trim=$malloc_trim -Dsparse=$sparse \
        -Dkvm=$kvm -Dhax=$hax -Dwhpx=$whpx -Dhvf=$hvf \