* Andy Lutomirski <l...@kernel.org> wrote:
> On Wed, Apr 10, 2019 at 4:43 AM Ingo Molnar <mi...@kernel.org> wrote: > > > > > > * Elena Reshetova <elena.reshet...@intel.com> wrote: > > > > > 2) Andy's tests, misc-tests: ./timing_test_64 10M sys_enosys > > > base: 10000000 loops in > > > 1.62224s = 162.22 nsec / loop > > > random_offset (prandom_u32() every syscall): 10000000 loops in > > > 1.64660s = 166.26 nsec / loop > > > > Stupid question, how did you manage to buil timing_test_64? Here it fails > > with a bog standard gcc 7.3.0 x86-64 distro toolchain: > > > > dagon:~/luto-misc-tests.git> make timing_test_64 > > g++ -m64 -o timing_test_64 -O2 -g -std=gnu++11 -pthread -Wall > > timing_test.cc -lrt -ldl > > /usr/bin/ld: /tmp/cc8VRkuV.o: relocation R_X86_64_32S against > > `.text.startup' can not be used when making a PIE object; recompile with > > -fPIC > > /usr/bin/ld: final link failed: Nonrepresentable section on > > outputcollect2: error: ld returned 1 exit status > > Makefile:39: recipe for target 'timing_test_64' failed > > > > I think your toolchain is screwy. If I create this file as ingo.c: > > #include <stdio.h> > > int main(int argc, char **argv) > { > printf("Hello world!"); > > return 0; > } > > And build it like this, it fails: > > $ gcc -o ingo -g ingo.c -pie > /usr/bin/ld: /tmp/ccofYU9N.o: relocation R_X86_64_32 against `.rodata' > can not be used when making a PIE object; recompile with -fPIC > /usr/bin/ld: final link failed: nonrepresentable section on output > collect2: error: ld returned 1 exit status > > Which I assume means that -pie requires -fPIC, and your toolchain is > screwed up and is defaulting to useless options. I'm guessing you > should file a bug against your distro gcc package. For me, it works > if I remove -pie. It's just a bog standard Ubuntu x86-64 installation. Thanks, Ingo