Comment by busterarm

3 days ago

Let's keep the CPU efficiency golf to Zachtronics games, please.

I/O is almost always the main bottleneck. I swear to god 99% of developers out there only know how to measure cpu cycles of their code so that's the only thing they optimize for. Call me after you've seen your jobs on your k8s clusters get slow because all of your jobs are inefficiently using local disk and wasting cycles waiting in queue for reads/writes. Or your DB replication slows down to the point that you have to choose between breaking the mirror and stop making money.

And older hardware consumes more power. That's the main driving factor between server hardware upgrades because you can fit more compute into your datacenter.

I agree with Carmack's assessment here, but most people reading are taking the wrong message away with them.

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busterarm

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_aavaa_  3 days ago

There's servers and there's all of the rest of consumer hardware.

I need to buy a new phone every few years simply because the manufacturer refuses to update it. Or they add progressively more computationally expensive effects that makes my old hardware crawl. Or the software I use only supports 2 old version of macOS. Or Microsoft decides that your brand new cpu is no good for win 11 because it's lacking a TPM. Or god help you if you try to open our poorly optimized electron app on your 5 year old computer.

  • busterarm  3 days ago

    But Carmack is clearly talking about servers here. That is my problem -- the main audience is going to read this and think about personal compute.

    All those situations you describe are also a choice made so that companies can make sales.

    • _aavaa_  3 days ago

      It shows up in different ways, and I agree that some of my examples are planned obsolescence.

      I'm not so sure they're that different though. I do think that in the end most boil down to the same problem: no emphasis or care about performance.

      Picking a programming paradigm that all but incentivizes N+1 selects is stupid. An N+1 select is not an I/O problem, it's a design problem.

wtetzner  3 days ago

> I/O is almost always the main bottleneck.

People say this all the time, and usually it's just an excuse not to optimize anything.

First, I/O can be optimized. It's very likely that most servers are either wasteful in the number of requests they make, or are shuffling more data around than necessary.

Beyond that though, adding slow logic on top of I/O latency only makes things worse.

Also, what does I/O being a bottleneck have to do with my browser consuming all of my RAM and using 120% of my CPU? Most people who say "I/O is the bottleneck" as a reason to not optimize only care about servers, and ignore the end users.

  • busterarm  3 days ago

    I/O _can_ be optimized. I know someone who had this as their fulltime job at Meta. Outside of that nobody is investing in it though.

    I'm a platform engineer for a company with thousands of microservices. I'm not thinking on your desktop scale. Our jobs are all memory hogs and I/O bound messes. Across all of the hardware we're buying we're using maybe 10% CPU. Peers I talk to at other companies are almost universally in the same situation.

    I'm not saying don't care about CPU efficiency, but I encounter dumb shit all the time like engineers asking us to run exotic new databases with bad licensing and no enterprise features just because it's 10% faster when we're nowhere near experiencing those kinds of efficiency problems. I almost never encounter engineers who truly understand or care about things like resource contention/utilization. Everything is still treated like an infinite pool with perfect 100% uptime, despite (at least) 20 years of the industry knowing better.