Thanks for the good questions. On Sun, Dec 29, 2024 at 4:10 PM andreas.elding via 9fans <9fans@9fans.net> wrote: > How was it presented to the users? Could they query to see the current > utilization of the system?
It looked very normal. To see what was running, you did ps. In the status, you could see that a process was on an AC. It looked a lot like a wired proc, save that no kernel code would run and interrupt a process on an AC. If you are familiar with plan 9 libthread, or goroutines, it was taking that non-preemptive idea just a bit further: your proc owned the core, until you were done. BTW, there are 512- and 1024-core risc-v systems in the works, and NIX looks pretty good for that kind of CPU. > How did you know that a job completed (or failed)? Just as with a process; you read /proc/pid/wait. It was very transparent. > > You mentioned it was a shared memory system, meaning it was in essence a > "very large SMP machine" from the view of the OS? Yes, with a slight change in view: the AC looked like a CPU, and there was shared memory, and it was coherent, but the AC scheduling was a different bit of code than normal process scheduling. > Could the NIX system only work with shared memory systems like that, or was > it possible to take many smaller independent systems and combine their > resources? My original idea in spring 2011, after talking to Shalf at LBL, was that we might have CPUs with hardware FIFOs communicating. When I got to lsub, Charles made the point: "you have a shared memory machine, might as well use it" -- and that made a lot of sense. So we used shared memory, and avoided a lot of headaches that Charles, jmk, Eric, and I had dealt with on Blue Gene. > > Anything you can say about the actual usage would be quite interesting - what > kind of applications are we talking? Was there commercial interest? Nobody used it. In 2006, there was a strong move to Linux, but there was still room for non-Linux approaches. By 2011, that option was almost gone. I gave talks on NIX and Plan 9 for about 10 years at various DOE labs, conferences, and universities; there was always interest, but "not Linux" became harder and harder to overcome. My last talk on NIX was 6 months after I left Sandia for Google, and it was more of a history lesson than anything. ron ------------------------------------------ 9fans: 9fans Permalink: https://9fans.topicbox.com/groups/9fans/T7692a612f26c8ec5-Meaa99ccddc16c65fcb9a8e51 Delivery options: https://9fans.topicbox.com/groups/9fans/subscription
