CBI NaCl is a project that improves Native Client's performance by allowing more relaxed instruction alignment invariants, while providing same level of security.
Here you can access the paper we published at NDSS BAR 2018:
The Effect of Instruction Padding on SFI Overhead

You can also access the project's artifact by downloading the following virtual machine. We recommend using VritalBox, but QEMU-KVM can be used with some workaround, as well.