4 ms·

I agree that single cache-line fetches are pretty poor for parallel vector units, but supporting the former in an environment designed for the latter doesn't se

I agree that single cache-line fetches are pretty poor for parallel vector units, but supporting the former in an environment designed for the latter doesn't seem to off-putting (the CM-5 did this).

DonHopkins 2y ago
By the way: Does your user name convolvotron refer to the hardware 3d audio audio processing system originally developed at NASA Ames Research? Such a cool name! And it says just what it does. https://spinoff.nasa.gov/node/8965 https://spinoff.nasa.gov/node/8965 https://spinoff.nasa.gov/sites/default/files/thumbnail0000_20020083312.pdf.jpg https://spinoff.nasa.gov/sites/default/files/thumbnail0000_2... https://pubs.aip.org/asa/jasa/article/92/4_Supplement/2376/730514/The-Convolvotron-Real-time-demonstration-of https://pubs.aip.org/asa/jasa/article/92/4_Supplement/2376/7... Body Electric supported the Convolvotron for visually programming VR simulations with 3D sound: https://news.ycombinator.com/item?id=24266722 https://news.ycombinator.com/item?id=24266722 Did you ever meet (or better yet get a tour of Ames from) the late Ron Reisman, and see the virtual reality, flight simulator, and air traffic control systems his research lab developed? Vertical Motion Simulator: https://www.youtube.com/watch?v=5-lHcv_olkE https://www.youtube.com/watch?v=5-lHcv_olkE Marvin Minsky flies a simulator and wears VR goggles: https://www.youtube.com/watch?v=mOKENF_-z8Y https://www.youtube.com/watch?v=mOKENF_-z8Y
- convolvatron 2y ago
  no. but thank you so much for the references. that's actually really great. I needed a username in the early 90s, I had just finished a paper where we microcoded a CM-2 to support high-throughput convolutions with spatially varying kernels for Hubble image correction (before the launched the eyeglasses mission), and I decided I could be the hero or anti-hero of convolution.
  - DonHopkins 2y ago
    Then you would probably appreciate one of the more obscure and specialized Kai Power Tools for Photoshop: KTP Convolver! https://www.macintoshrepository.org/724-kpt-convolver-1-0 https://www.macintoshrepository.org/724-kpt-convolver-1-0 I can't find any demos of it on youtube, but it's the kind of obscure retro thing that LGR loves to review. He's really into the better known Kai Power Goo, which is a bit more accessible to kids than KPT Convolver: https://www.youtube.com/watch?v=xt06OSIQ0PE https://www.youtube.com/watch?v=xt06OSIQ0PE
- jimmySixDOF 2y ago
  It would be very interesting to dust off some of those old projects with modern affordances like not needing 1 SGI machine per eye lol but to review the first principles thinking in the problem spaces you guys looked at like air traffic control which is still the same use case and XR should have better chance today of making out of R&D labs onto a shop floor. I have seen talks from Tom Furness about the early applications being tested and seems like we are just now getting to a place on the development curve where some of them might just be practical. Thanks for all those links they will keep me busy for a while !
danjl 2y ago
I think all the mobile GPUs use UMA. I think the tradeoff point is some complicated function of power envelopes and the benefit of more, though slower, memory vs raw performance at any power or $ cost. Though there are several dozen important algorithms that run much better on GPUs, there are really only two of them, 3D graphics and ML tensors, that have had a big consumer and broad professional appeal.
sliken 2y ago
Why? Not like there's a single memory channel. Keeping the memory controller busy with tons of pending requests is a great way to make use of a large fraction of the total memory bandwidth. The M2 Ultra has 32 or 64 memory channels, a cache line pending for each would allow good bandwidth utilization.

I agree that single cache-line fetches are pretty poor for parallel vector units, but supporting the former in an environment designed for the latter doesn't seem to off-putting (the CM-5 did this).

DonHopkins 2y ago

By the way: Does your user name convolvotron refer to the hardware 3d audio audio processing system originally developed at NASA Ames Research? Such a cool name! And it says just what it does. https://spinoff.nasa.gov/node/8965 https://spinoff.nasa.gov/node/8965 https://spinoff.nasa.gov/sites/default/files/thumbnail0000_20020083312.pdf.jpg https://spinoff.nasa.gov/sites/default/files/thumbnail0000_2... https://pubs.aip.org/asa/jasa/article/92/4_Supplement/2376/730514/The-Convolvotron-Real-time-demonstration-of https://pubs.aip.org/asa/jasa/article/92/4_Supplement/2376/7... Body Electric supported the Convolvotron for visually programming VR simulations with 3D sound: https://news.ycombinator.com/item?id=24266722 https://news.ycombinator.com/item?id=24266722 Did you ever meet (or better yet get a tour of Ames from) the late Ron Reisman, and see the virtual reality, flight simulator, and air traffic control systems his research lab developed? Vertical Motion Simulator: https://www.youtube.com/watch?v=5-lHcv_olkE https://www.youtube.com/watch?v=5-lHcv_olkE Marvin Minsky flies a simulator and wears VR goggles: https://www.youtube.com/watch?v=mOKENF_-z8Y https://www.youtube.com/watch?v=mOKENF_-z8Y

convolvatron 2y ago
no. but thank you so much for the references. that's actually really great. I needed a username in the early 90s, I had just finished a paper where we microcoded a CM-2 to support high-throughput convolutions with spatially varying kernels for Hubble image correction (before the launched the eyeglasses mission), and I decided I could be the hero or anti-hero of convolution.
- DonHopkins 2y ago
  Then you would probably appreciate one of the more obscure and specialized Kai Power Tools for Photoshop: KTP Convolver! https://www.macintoshrepository.org/724-kpt-convolver-1-0 https://www.macintoshrepository.org/724-kpt-convolver-1-0 I can't find any demos of it on youtube, but it's the kind of obscure retro thing that LGR loves to review. He's really into the better known Kai Power Goo, which is a bit more accessible to kids than KPT Convolver: https://www.youtube.com/watch?v=xt06OSIQ0PE https://www.youtube.com/watch?v=xt06OSIQ0PE
jimmySixDOF 2y ago
It would be very interesting to dust off some of those old projects with modern affordances like not needing 1 SGI machine per eye lol but to review the first principles thinking in the problem spaces you guys looked at like air traffic control which is still the same use case and XR should have better chance today of making out of R&D labs onto a shop floor. I have seen talks from Tom Furness about the early applications being tested and seems like we are just now getting to a place on the development curve where some of them might just be practical. Thanks for all those links they will keep me busy for a while !

danjl 2y ago

I think all the mobile GPUs use UMA. I think the tradeoff point is some complicated function of power envelopes and the benefit of more, though slower, memory vs raw performance at any power or $ cost. Though there are several dozen important algorithms that run much better on GPUs, there are really only two of them, 3D graphics and ML tensors, that have had a big consumer and broad professional appeal.

sliken 2y ago

Why? Not like there's a single memory channel. Keeping the memory controller busy with tons of pending requests is a great way to make use of a large fraction of the total memory bandwidth. The M2 Ultra has 32 or 64 memory channels, a cache line pending for each would allow good bandwidth utilization.