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I find it odd that they would publish a video showing performance numbers from out of date hardware. I mean I believe you - I watched the presentation in their

I find it odd that they would publish a video showing performance numbers from out of date hardware. I mean I believe you - I watched the presentation in their custom processor and it’s quite impressive. Just weird that they’re showing old performance numbers. Perhaps this video is old.

grecy 7y ago
There is speculation going around the "big rewrite" Elon mentioned last week is actually porting the code to run natively on the new hardware. Speculation says it's just been running in an emulation layer, but now they're about to unleash the full potential of the hardware. If true, it makes sense the video would also have been captured using this emulation layer, explaining why it's not latest-and-greatest-fast.
- TaylorAlexander 7y ago
  Ah that would make some sense. Certainly I’m expecting extremely good performance from the new computer once everything is running natively.
- mike_d 7y ago
  If that is true you should call in to question the integrity of a company that would run life-critical software on a non-RTOS.
  - TaylorAlexander 7y ago
    Nobody said anything about whether or not there is an RTOS involved.
  - eru 7y ago
    Realtime has nothing to do with absolute performance. It's about meeting your deadlines. And, of course, often real-time systems have much worse throughput performance than a non-real-time system on the same hardware. After all, latency guarantees are not free.
    - Dylan16807 7y ago
      Yeah, until we're above 500Hz I'd rather have a significantly faster non-realtime main system, with a small realtime watchdog/backup.
      - eru 7y ago
        Even a guaranteed 10Hz, ie 100ms reaction time, is better than what humans routinely do. And yes, in practice you will probably combine a small real-time core with most of the code (by volume) running non-real time. Lots of one-time setup at the beginning of the right, or longer-range route replanning doesn't need to finish within tight deadlines. The human analogue is your co-pilot reading the map; or when you are fiddling with the aircon or radio dial.
    - mike_d 7y ago
      Yup. I think we agree on that. It doesn't matter if you have a highly performant pipeline for detecting other cars if you have a random 200 ms VM pause as another car blows a stop sign in front of you.
      - Dylan16807 7y ago
        ...but if it starts braking hard in 250ms that's still a very superhuman reaction time.
        RugnirViking 7y ago
        As humans we know our reaction times - you naturally slow down as you get to a junction or navigate crowded or tricky traffic conditions to give yourself as much of a chance as possible to react. This is the thinking behind many types of speed control street layouts. You should also know where to look to anticipate where danger is most likely to come from, and be ready with some kind of action. This is why we do hazard identification tests as part of the driving test - looking in the right directions at the right times is crucial for operating a vehicle safely. 250ms is a fairly average reaction time for something visual that you are ready for - but you should really be giving yourself as much time as possible - if somebody bombs past a traffic light at 70mph, even if it is green, most people would agree that it was an unsafe move. This goes doubly for an autonomous car, that is unable to play the positioning negotiation game that humans are masters of as a result of being social creatures.

grecy 7y ago

There is speculation going around the "big rewrite" Elon mentioned last week is actually porting the code to run natively on the new hardware. Speculation says it's just been running in an emulation layer, but now they're about to unleash the full potential of the hardware. If true, it makes sense the video would also have been captured using this emulation layer, explaining why it's not latest-and-greatest-fast.

TaylorAlexander 7y ago
Ah that would make some sense. Certainly I’m expecting extremely good performance from the new computer once everything is running natively.
mike_d 7y ago
If that is true you should call in to question the integrity of a company that would run life-critical software on a non-RTOS.
- TaylorAlexander 7y ago
  Nobody said anything about whether or not there is an RTOS involved.
- eru 7y ago
  Realtime has nothing to do with absolute performance. It's about meeting your deadlines. And, of course, often real-time systems have much worse throughput performance than a non-real-time system on the same hardware. After all, latency guarantees are not free.
  - Dylan16807 7y ago
    Yeah, until we're above 500Hz I'd rather have a significantly faster non-realtime main system, with a small realtime watchdog/backup.
    - eru 7y ago
      Even a guaranteed 10Hz, ie 100ms reaction time, is better than what humans routinely do. And yes, in practice you will probably combine a small real-time core with most of the code (by volume) running non-real time. Lots of one-time setup at the beginning of the right, or longer-range route replanning doesn't need to finish within tight deadlines. The human analogue is your co-pilot reading the map; or when you are fiddling with the aircon or radio dial.
  - mike_d 7y ago
    Yup. I think we agree on that. It doesn't matter if you have a highly performant pipeline for detecting other cars if you have a random 200 ms VM pause as another car blows a stop sign in front of you.
    - Dylan16807 7y ago
      ...but if it starts braking hard in 250ms that's still a very superhuman reaction time.
      - RugnirViking 7y ago
        As humans we know our reaction times - you naturally slow down as you get to a junction or navigate crowded or tricky traffic conditions to give yourself as much of a chance as possible to react. This is the thinking behind many types of speed control street layouts. You should also know where to look to anticipate where danger is most likely to come from, and be ready with some kind of action. This is why we do hazard identification tests as part of the driving test - looking in the right directions at the right times is crucial for operating a vehicle safely. 250ms is a fairly average reaction time for something visual that you are ready for - but you should really be giving yourself as much time as possible - if somebody bombs past a traffic light at 70mph, even if it is green, most people would agree that it was an unsafe move. This goes doubly for an autonomous car, that is unable to play the positioning negotiation game that humans are masters of as a result of being social creatures.