$ git clone -n https://src.fedoraproject.org/rpms/gperftools.git /var/lib/mock/f40-build-2241114-53661/root/chroot_tmpdir/scmroot/gperftools
Cloning into '/var/lib/mock/f40-build-2241114-53661/root/chroot_tmpdir/scmroot/gperftools'...
$ git fetch origin 0e8898ba1083938248c3128185eaf8ef33c9cd02:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gperftools
 * [new ref]         0e8898ba1083938248c3128185eaf8ef33c9cd02 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0e8898b update to 2.14, add fix for i686/ppc64le