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This OS doesn't require an MMU or protected memory. I wonder if a processor architecture that lacks those features could yield much higher performance due to le

by sprash 7y ago

This OS doesn't require an MMU or protected memory. I wonder if a processor architecture that lacks those features could yield much higher performance due to less complexity, reduced memory latency or less cache miss penalty. Will it be enough to mitigate the perormance penalty of runing code in the Dis VM?

soraminazuki 7y ago
You'd have to compensate for the lack of memory protection by running all unprivileged code in a VM, which would very likely introduce its own class of complexities and performance penalties.
- henesy 7y ago
  Inferno instances are really meant to be compartments for individual programs more than a desktop OS in and of itself. Dis VM instances are super light… you wouldn't really be needing to worry much about running a large number of them. Point aside in many cases you can sandbox applications in crafted namespaces using spawn and flags like NODEVS.
- sprash 7y ago
  Inferno already runs all unprivileged code in a VM. When I installed it on a Raspberry Pi for example could disable or enable its MMU, it didn't make a difference at all.
- tinus_hn 7y ago
  People always defend Java as if these penalties don’t exist somehow.
  - sprash 7y ago
    The question was more about how the big the penalty is compared to running a MMU. Also according to my (admittedly rather basic) tests the DIS VM performs far better than JVM.
the_why_of_y 7y ago
You could do that (see Singularity OS [0] and Midori [1]), but recently it was discovered that it wouldn't work on modern out-of-order CPUs due to Spectre [2]. [0] https://research.cs.wisc.edu/areas/os/Seminar/schedules/papers/Deconstructing_Process_Isolation_final.pdf https://research.cs.wisc.edu/areas/os/Seminar/schedules/pape... [1] http://joeduffyblog.com/2015/11/03/blogging-about-midori/ http://joeduffyblog.com/2015/11/03/blogging-about-midori/ [2] https://arxiv.org/abs/1902.05178 https://arxiv.org/abs/1902.05178

by sprash 7y ago

soraminazuki 7y ago

You'd have to compensate for the lack of memory protection by running all unprivileged code in a VM, which would very likely introduce its own class of complexities and performance penalties.

henesy 7y ago
Inferno instances are really meant to be compartments for individual programs more than a desktop OS in and of itself. Dis VM instances are super light… you wouldn't really be needing to worry much about running a large number of them. Point aside in many cases you can sandbox applications in crafted namespaces using spawn and flags like NODEVS.
sprash 7y ago
Inferno already runs all unprivileged code in a VM. When I installed it on a Raspberry Pi for example could disable or enable its MMU, it didn't make a difference at all.
tinus_hn 7y ago
People always defend Java as if these penalties don’t exist somehow.
- sprash 7y ago
  The question was more about how the big the penalty is compared to running a MMU. Also according to my (admittedly rather basic) tests the DIS VM performs far better than JVM.

the_why_of_y 7y ago

You could do that (see Singularity OS [0] and Midori [1]), but recently it was discovered that it wouldn't work on modern out-of-order CPUs due to Spectre [2]. [0] https://research.cs.wisc.edu/areas/os/Seminar/schedules/papers/Deconstructing_Process_Isolation_final.pdf https://research.cs.wisc.edu/areas/os/Seminar/schedules/pape... [1] http://joeduffyblog.com/2015/11/03/blogging-about-midori/ http://joeduffyblog.com/2015/11/03/blogging-about-midori/ [2] https://arxiv.org/abs/1902.05178 https://arxiv.org/abs/1902.05178