I tested with utopic-proposed as well. 

installing libhwloc-dev installed 19 total packages from a fresh docker image. 

These were the packages: 
# dpkg -l | grep hwloc
ii  libhwloc-dev:amd64         1.8-1ubuntu1.14.10.1         amd64        Hierarchical view of the machine - static libs and headers
ii  libhwloc-plugins           1.8-1ubuntu1.14.10.1         amd64        Hierarchical view of the machine - plugins
ii  libhwloc5:amd64            1.8-1ubuntu1.14.10.1         amd64        Hierarchical view of the machine - shared libs

New dependency tree
# apt-get install libhwloc-dev
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following extra packages will be installed:
  libc-dev-bin libc6 libc6-dev libhwloc-plugins libhwloc5 libltdl7 libnuma1 libpci-dev libpci3 libpciaccess0 libxml2 libxml2-dev linux-libc-dev manpages
  manpages-dev ocl-icd-libopencl1 sgml-base xml-core zlib1g-dev
Suggested packages:
  glibc-doc libhwloc-contrib-plugins pciutils pkg-config man-browser opencl-icd sgml-base-doc debhelper
The following NEW packages will be installed:
  libc-dev-bin libc6-dev libhwloc-dev libhwloc-plugins libhwloc5 libltdl7 libnuma1 libpci-dev libpci3 libpciaccess0 libxml2 libxml2-dev linux-libc-dev
  manpages manpages-dev ocl-icd-libopencl1 sgml-base xml-core zlib1g-dev
The following packages will be upgraded:
  libc6
1 upgraded, 19 newly installed, 0 to remove and 24 not upgraded.
Need to get 11.8 MB of archives.
After this operation, 27.0 MB of additional disk space will be used.


I tested a baseline with the original and the problem was not as large as on trusty. 

# dpkg -l | grep hwloc
ii  libhwloc-dev:amd64         1.8-1ubuntu1                 amd64        Hierarchical view of the machine - static libs and headers
ii  libhwloc-plugins           1.8-1ubuntu1                 amd64        Hierarchical view of the machine - plugins
ii  libhwloc5:amd64            1.8-1ubuntu1                 amd64        Hierarchical view of the machine - shared libs


Old dependency tree: 

# apt-get install libhwloc-dev
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following extra packages will be installed:
  binutils cpp cpp-4.9 dkms fakeroot fglrx-updates-core gcc gcc-4.9 lib32gcc1
  libasan1 libatomic1 libc-dev-bin libc6 libc6-dev libc6-i386 libcilkrts5
  libcloog-isl4 libfakeroot libgcc-4.9-dev libgomp1 libhwloc-plugins libhwloc5
  libisl10 libitm1 liblsan0 libltdl7 libmpc3 libmpfr4 libnuma1 libpci-dev
  libpci3 libpciaccess0 libquadmath0 libtsan0 libubsan0 libxml2 libxml2-dev
  linux-libc-dev make manpages manpages-dev patch sgml-base xml-core
  zlib1g-dev
Suggested packages:
  binutils-doc cpp-doc gcc-4.9-locales dpkg-dev debhelper gcc-multilib
  autoconf automake libtool flex bison gdb gcc-doc gcc-4.9-multilib
  gcc-4.9-doc libgcc1-dbg libgomp1-dbg libitm1-dbg libatomic1-dbg libasan1-dbg
  liblsan0-dbg libtsan0-dbg libubsan0-dbg libcilkrts5-dbg libquadmath0-dbg
  glibc-doc libhwloc-contrib-plugins pciutils pkg-config make-doc man-browser
  ed diffutils-doc sgml-base-doc
The following NEW packages will be installed:
  binutils cpp cpp-4.9 dkms fakeroot fglrx-updates-core gcc gcc-4.9 lib32gcc1
  libasan1 libatomic1 libc-dev-bin libc6-dev libc6-i386 libcilkrts5
  libcloog-isl4 libfakeroot libgcc-4.9-dev libgomp1 libhwloc-dev
  libhwloc-plugins libhwloc5 libisl10 libitm1 liblsan0 libltdl7 libmpc3
  libmpfr4 libnuma1 libpci-dev libpci3 libpciaccess0 libquadmath0 libtsan0
  libubsan0 libxml2 libxml2-dev linux-libc-dev make manpages manpages-dev
  patch sgml-base xml-core zlib1g-dev
The following packages will be upgraded:
  libc6
1 upgraded, 45 newly installed, 0 to remove and 24 not upgraded.
Need to get 59.3 MB of archives.
After this operation, 226 MB of additional disk space will be used.