5 ms·

Are you talking about shared libraries, that kind of deduplication? Although true, that probably isn't really very significant compared to the vast wasted reso

• jacquesm 11y ago
  Yes, but then rather than shared libraries the kind of de-duplication the kernel will do when it runs multiple instances of the same binary. This is (normally) very cache and IO efficient since it is done at the VM page level. I also don't quite understand how one can reserve CPU cycles, memory and deliver IO guarantees without the same over-provisioning that you'd have to do using regular virtualization. After all, as soon as you make a guarantee nobody else can use that which is left over, so in that respect I see little difference between virtualizing the entire OS+app versus re-using the kernel (ok, that does save you the overhead of the kernel itself but that's not a huge difference unless you run a very large number of VMs on a single machine).
  • menage 11y ago
    But you can make guarantees to the critical jobs (up to the total size of the machine) and then let batch jobs (with less time-sensitive requirements) run best-effort in the slack. In the event that there ends up being no best-effort resources available on a machine for a significant period of time (because all the user-facing jobs are busy and using their guaranteed resources) Borg will shift the starving batch jobs to other machines that aren't so busy.