* Martin Buchholz: > Here's an experiment using the 3 competing open source linkers to link > hotspot. This confirms that lld is faster than gold is faster than > bfd, but is the one second saving worth the engineering effort? > > $ (BUILDDIR=$HOME/ws/jdk/build/linux-x86_64-server-release; for > linker in bfd gold lld; do echo --- $linker ---; time /usr/bin/g++ > -fuse-ld=$linker -Wl,--hash-style=both -Wl,-z,defs -Wl,-z,noexecstack > -Wl,-O1 -Wl,-z,relro -m64 -static-libstdc++ -static-libgcc -shared > -m64 -Wl,-version-script=$BUILDDIR/hotspot/variant-server/libjvm/mapfile > -Wl,-soname=libjvm.so -o > $BUILDDIR/support/modules_libs/java.base/server/libjvm.so > @$BUILDDIR/hotspot/variant-server/libjvm/objs/_BUILD_LIBJVM_objectfilenames.txt > -lm -ldl -lpthread; done) > --- bfd --- > /usr/bin/g++ -fuse-ld=$linker -Wl,--hash-style=both -Wl,-z,defs > -Wl,-O1 -m6 1.31s user 0.36s system 99% cpu 1.669 total > --- gold --- > /usr/bin/g++ -fuse-ld=$linker -Wl,--hash-style=both -Wl,-z,defs > -Wl,-O1 -m6 0.42s user 0.11s system 99% cpu 0.537 total > --- lld --- > /usr/bin/g++ -fuse-ld=$linker -Wl,--hash-style=both -Wl,-z,defs > -Wl,-O1 -m6 0.25s user 0.20s system 145% cpu 0.310 total
Do the constituent object files have debugging information? Sub-second processing times for ~350 MiB of output are rather impressive. On a Sandybridge-era Xeon (probably without SSD storage), I see a change from 13 seconds to 8 seconds (BFD to gold). This is the first libjvm.so link from “make images”, and the output includes (apparently full) debugging information. Thanks, Florian
