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   silverwizard (silverwizard@convenient.email)'s status on Friday, 05-Jul-2024 03:44:18 JST silverwizard

   You can't scale a single-threaded process by adding more logical CPUs.

   Why is this something that confuses people?

   • Embed this notice
     silverwizard (silverwizard@convenient.email)'s status on Friday, 05-Jul-2024 05:01:06 JST silverwizard

     in reply to

     • Jonathan Lamothe
     @jlamothe it doesn't matter if the execution is out of order - the problem is that when you've got a CPU pegged, the second idle CPU doesn't help.
   • Embed this notice
     Jonathan Lamothe (jlamothe@fosstodon.org)'s status on Friday, 05-Jul-2024 05:01:07 JST Jonathan Lamothe

     in reply to

     @silverwizard There is out-of-order execution, but modern CPUs aleady do this anyway. I don't know that adding a logical CPU could really help.

     silverwizard likes this.
   • Embed this notice
     Jonathan Lamothe (jlamothe@fosstodon.org)'s status on Friday, 05-Jul-2024 05:28:12 JST Jonathan Lamothe

     in reply to

     @silverwizard out of order operation isn't just about changing the order of the operations. It lets you (sometimes) pre-compute the result of future instructions as long as they're not based on the output of the previous ones enabling you to parallelize what would otherwise be a single execution thread. I imagine there's a point of diminishing returns though.
     https://www.youtube.com/watch?v=jNC9LPc3BI0

     Perhaps I'm misunderstanding what you're saying?

   • Embed this notice
     silverwizard (silverwizard@convenient.email)'s status on Friday, 05-Jul-2024 05:28:12 JST silverwizard

     in reply to

     • Jonathan Lamothe
     @jlamothe Yes, it's theoretically possible for there to be value. But it's not going to affect on the scale of "our system is constantly pegged"
   • Embed this notice
     Alexandre Oliva (lxo@gnusocial.net)'s status on Friday, 05-Jul-2024 05:42:49 JST Alexandre Oliva

     in reply to

     • Jonathan Lamothe
     all the out-of-order execution occurs inside a single CPU
     adding more CPUs won't help speed up a single-threaded program
     
     picture a call center
     an attendant is like a CPU
     the attendant can pay attention to one customer at a time. the customer may issue multiple requests/instructions, and an attendant with out-of-order operation may be able to look into and satisfy some of the requests before other earlier ones
     however, adding more attendants wouldn't help this one customer get faster service, unless the customer started multiple calls (threads or processes), or the attendants could pass customer requests and context on to each other (that's not permitted by the call center design; they can only transfer entire calls)