5 ms·

> Let's not drastically increase job requirements for no good reason. Well, I would say that it's a very good reason, and that learning about branch prediction

> Let's not drastically increase job requirements for no good reason. Well, I would say that it's a very good reason, and that learning about branch prediction and caches is not a "drastic" step by any means. Is there any software that you write whose users would not be made happier if the software performed better? Any at all? > Many of these platforms have undocumented CPU instructions You don't need to know the secrets of a platform to understand branch prediction and caches, or to use that knowledge to produce software that performs far better than software written without that knowledge. You don't need to know the platform on a logic gate level, you need to understand how the platform executes your code, so that you can take advantage of the strengths of the platform. You don't need to know any hidden instructions or secrets to take advantage of the platform. > we've had CPU-level issues like spectre and meltdown introduced that affected performance in some cases those things didn't affect performance, the fixes for those things did. The fixes also required no code changes outside of the firmware and the operating system, and knowing the platform is still the best way to write performant software, no matter what is going on to avoid hardware vulnerabilities.

vsareto 7y ago
>Is there any software that you write whose users would not be made happier if the software performed better? Any at all? I'd say security is a bigger issue than performance most of the time. And most gains are going to happen within the code itself by, e.g., not writing n^2 when there's a log(n) solution or something similar. Plus we're talking about javascript, and that's likely to be software with network concerns, so your optimizations might be a rounding error compared to performance degradation from slow network connections. >You don't need to know any hidden instructions or secrets to take advantage of the platform. You don't know what they do though. Some of those ops could be more advantageous to performance to use in some cases. You can't fully know the platform if there are secret ops. You can still make optimizations with partial knowledge, but don't pretend to know the platform when the platform manufacturer doesn't tell you everything about it. >The fixes also required no code changes outside of the firmware and the operating system, and knowing the platform is still the best way to write performant software, no matter what is going on to avoid hardware vulnerabilities. Good algorithm knowledge and practice is the most cost-effective way of writing performant code and is more than likely going to be the lion's share of issues.
- kasey_junk 7y ago
  > Good algorithm knowledge and practice is the most cost-effective way of writing performant code I’d love to see that common thought validated because in practice I’ve seen it to not be true at all. There are lots of cases where the complexity effects of the algorithm are swamped by cache effects. In fact basic foundational assumptions about complexity analysis are dangerously untrue on modern systems. In my experience in either high throughput or low latency systems algorithmic complexity is never the issue. It’s always cache coherence, CPU prefectching/prediction, lock contention or over copying of data.
  - vsareto 7y ago
    >I’d love to see that common thought validated because in practice I’ve seen it to not be true at all. If you have Javascript devs that came out of some boot camp with no knowledge of either, do you teach algorithms 101 or low-level CPU programming 101 first? I would argue your codebase would benefit from teaching them algorithms first, then the other one. >In my experience in either high throughput or low latency systems algorithmic complexity is never the issue. Do you encounter those workloads written in Javascript often?
    - emsy 7y ago
      >If you have Javascript devs that came out of some boot camp Do you also go to a doctor that came out of a bootcamp? Is your house built by a constructor that came out of a bootcamp? Would you fly with an aviator that came out of a bootcamp? Would you run banking software made by a developer that came out of a bootcamp?
      - NotATroll 7y ago
        So how, precisely, is anyone supposed to get experience if it's unacceptable to hire them fresh out of "boot camp". Even if you go "INTERNSHIP". Well what, is everyone supposed to stick the unpaid intern on toy apps that don't give them any actual real world experience writing actual production software? Cause then the next argument will just be "Do you also go to a doctor that came out of an internship? Is you house built by a constructor that came out of an internship?". Elitism at its finest.

vsareto 7y ago

>Is there any software that you write whose users would not be made happier if the software performed better? Any at all? I'd say security is a bigger issue than performance most of the time. And most gains are going to happen within the code itself by, e.g., not writing n^2 when there's a log(n) solution or something similar. Plus we're talking about javascript, and that's likely to be software with network concerns, so your optimizations might be a rounding error compared to performance degradation from slow network connections. >You don't need to know any hidden instructions or secrets to take advantage of the platform. You don't know what they do though. Some of those ops could be more advantageous to performance to use in some cases. You can't fully know the platform if there are secret ops. You can still make optimizations with partial knowledge, but don't pretend to know the platform when the platform manufacturer doesn't tell you everything about it. >The fixes also required no code changes outside of the firmware and the operating system, and knowing the platform is still the best way to write performant software, no matter what is going on to avoid hardware vulnerabilities. Good algorithm knowledge and practice is the most cost-effective way of writing performant code and is more than likely going to be the lion's share of issues.

kasey_junk 7y ago
> Good algorithm knowledge and practice is the most cost-effective way of writing performant code I’d love to see that common thought validated because in practice I’ve seen it to not be true at all. There are lots of cases where the complexity effects of the algorithm are swamped by cache effects. In fact basic foundational assumptions about complexity analysis are dangerously untrue on modern systems. In my experience in either high throughput or low latency systems algorithmic complexity is never the issue. It’s always cache coherence, CPU prefectching/prediction, lock contention or over copying of data.
- vsareto 7y ago
  >I’d love to see that common thought validated because in practice I’ve seen it to not be true at all. If you have Javascript devs that came out of some boot camp with no knowledge of either, do you teach algorithms 101 or low-level CPU programming 101 first? I would argue your codebase would benefit from teaching them algorithms first, then the other one. >In my experience in either high throughput or low latency systems algorithmic complexity is never the issue. Do you encounter those workloads written in Javascript often?
  - emsy 7y ago
    >If you have Javascript devs that came out of some boot camp Do you also go to a doctor that came out of a bootcamp? Is your house built by a constructor that came out of a bootcamp? Would you fly with an aviator that came out of a bootcamp? Would you run banking software made by a developer that came out of a bootcamp?
    - NotATroll 7y ago
      So how, precisely, is anyone supposed to get experience if it's unacceptable to hire them fresh out of "boot camp". Even if you go "INTERNSHIP". Well what, is everyone supposed to stick the unpaid intern on toy apps that don't give them any actual real world experience writing actual production software? Cause then the next argument will just be "Do you also go to a doctor that came out of an internship? Is you house built by a constructor that came out of an internship?". Elitism at its finest.