4 ms·

No it's not. Research generational garbage collection.

by zelly 6y ago

ncmncm 6y ago
Research Java.
- pjmlp 6y ago
  https://www.businesswire.com/news/home/20090302005701/en/Thales-Air-Systems-Selects-Aonix-PERC-Ultra https://www.businesswire.com/news/home/20090302005701/en/Tha...
  - MaxBarraclough 6y ago
    Interesting read, thanks. The cynic in me thinks 'deterministic garbage collection' is trivial depending on how you define it. 1. Start off with an ordinary JVM with a non-concurrent, non-parallel GC. Doesn't matter if it's generational. 2. Take an extremely conservative estimate of the worst-case full-GC pause time, given the hardware (ideally with excessively powerful hardware) 3. Set up the system to invoke full-GC every frame We've now defined a system that will cope with GC pauses just fine, but we haven't done any real engineering. Their offering clearly isn't that lazy, they've apparently written their own AOT compiler, but it's hard to gauge how technically impressive their GC is.
    - pjmlp 6y ago
      I can post other articles, unfortunately the anti-GC crowd (in general) seems to think GC == whatever I know of the JVM on my computer and is completely oblivious of the various kinds of options available out there. Ironically it tends to be the same crowd that is unware that high performance C usually doesn't use libc malloc()/free(), and there are companies that used to make a business out of selling specialized heap management libraries.
      - MaxBarraclough 6y ago
        I was just wondering what these guys specifically had done. The new GCs in HotSpot - ZGC and Shenandoah - are extremely impressive technologies. I wonder if the PERC Ultra virtual machine does anything similar, or if it's just a simple GC with a cautious approach to timing commitments, which seems more likely to me.
        pjmlp 6y ago
        Real Time Java has multiple ways to manage memory including arenas and deadlines for GC actions, Aicas is the current steward company of the specification. https://www.aicas.com/download/rtsj/rtsj_76.pdf https://www.aicas.com/download/rtsj/rtsj_76.pdf Books like "Hard Realtime Garbage Collection in Modern Object Oriented Programming Languages", from one of the Aicas' founders are quite interesting reads. https://www.amazon.com/Realtime-Collection-Oriented-Programming-Languages/dp/3831138931 https://www.amazon.com/Realtime-Collection-Oriented-Programm... Many discuss drop frames and jitter, while forgetting that a couple of ms more can result in someone's death in industrial automation or getting the wrong guys dead in weapon control systems.

No it's not. Research generational garbage collection.

by zelly 6y ago

No it's not. Research generational garbage collection.

ncmncm 6y ago

Research Java.

pjmlp 6y ago
https://www.businesswire.com/news/home/20090302005701/en/Thales-Air-Systems-Selects-Aonix-PERC-Ultra https://www.businesswire.com/news/home/20090302005701/en/Tha...
- MaxBarraclough 6y ago
  Interesting read, thanks. The cynic in me thinks 'deterministic garbage collection' is trivial depending on how you define it. 1. Start off with an ordinary JVM with a non-concurrent, non-parallel GC. Doesn't matter if it's generational. 2. Take an extremely conservative estimate of the worst-case full-GC pause time, given the hardware (ideally with excessively powerful hardware) 3. Set up the system to invoke full-GC every frame We've now defined a system that will cope with GC pauses just fine, but we haven't done any real engineering. Their offering clearly isn't that lazy, they've apparently written their own AOT compiler, but it's hard to gauge how technically impressive their GC is.
  - pjmlp 6y ago
    I can post other articles, unfortunately the anti-GC crowd (in general) seems to think GC == whatever I know of the JVM on my computer and is completely oblivious of the various kinds of options available out there. Ironically it tends to be the same crowd that is unware that high performance C usually doesn't use libc malloc()/free(), and there are companies that used to make a business out of selling specialized heap management libraries.
    - MaxBarraclough 6y ago
      I was just wondering what these guys specifically had done. The new GCs in HotSpot - ZGC and Shenandoah - are extremely impressive technologies. I wonder if the PERC Ultra virtual machine does anything similar, or if it's just a simple GC with a cautious approach to timing commitments, which seems more likely to me.
      - pjmlp 6y ago
        Real Time Java has multiple ways to manage memory including arenas and deadlines for GC actions, Aicas is the current steward company of the specification. https://www.aicas.com/download/rtsj/rtsj_76.pdf https://www.aicas.com/download/rtsj/rtsj_76.pdf Books like "Hard Realtime Garbage Collection in Modern Object Oriented Programming Languages", from one of the Aicas' founders are quite interesting reads. https://www.amazon.com/Realtime-Collection-Oriented-Programming-Languages/dp/3831138931 https://www.amazon.com/Realtime-Collection-Oriented-Programm... Many discuss drop frames and jitter, while forgetting that a couple of ms more can result in someone's death in industrial automation or getting the wrong guys dead in weapon control systems.