6 ms·

I don't like this argument for three reasons: 1. The single thread performance gap is very small (5-10% depending on application) or even non-existent in some

I don't like this argument for three reasons: 1. The single thread performance gap is very small (5-10% depending on application) or even non-existent in some cases. 2. Your computer runs more than one process at any given moment. The more cores, the more processes you can run without an impact on performance 3. That single core performance comes at the cost of efficiency and general power usage. Intel has had to clock their 14nm process very high to achieve that small lead in single thread performance.

Theodores 6y ago
The key words in the parent post are 'for me'. Imagine you have a single core compilation process that takes two minutes that you must run 50 times a day. This can happen. Ten percent brings 12 seconds per compile or ten minutes a day. This might not sound great but it means you can get an extra five compiles done. You can also get increased likelihood that you can remember what you were working on. Therefore the marginal gain in single thread performance is well worth having in this use case. The expense of genuine Intel becomes worth it even if you don't have so many cores.
- throwaway_pdp09 6y ago
  I have a dual core dev machine. Using -j 2 builds twice as fast (approx 35 mins -> 17 mins). Are current compiles really obligatory single thread? Because I sure would like to prop up intel with my wallet.
  - tbrock 6y ago
    Anything JavaScript for example is single threaded for the most part. Also something like linking is typically in parallelized.
    - jatone 6y ago
      thats not the compilation process. that's just javascript. the compilation definitely has parallelism.
      - tbrock 6y ago
        You’d be surprised...
  - chitza 6y ago
    Most web development toolchains depend on Node.js, which compiles on a single core.
    - kohtatsu 6y ago
      Node takes advantage of multiple cores. The code is all async by default and that is easy to load onto green threads. This used to be implemented with callback hell, now it's Promises which is actually really cosy (and what Rust is adopting). Random article I found on it: https://medium.com/better-programming/is-node-js-really-single-threaded-7ea59bcc8d64 https://medium.com/better-programming/is-node-js-really-sing...
    - oppositelock 6y ago
      Sure, but you're also running a browser at the same time probably with a ton of tabs open as separate processes. Our computers do quite a lot these days, in parallel, and more cores help. Both AMD and Intel are ridiculously fast! You can't really go wrong with either.
    - jatone 6y ago
      which then shard out to multi processes, still benefitting from more cores being available. I know of at least a few build processes that support that model for node.
  - benibela 6y ago
    FreePascal is single threaded But it is also like 10 times faster than other compilers.
- jatone 6y ago
  fix your compilation process. there are few long running workloads that don't benefit from parallelism.
- rumanator 6y ago
  > Imagine you have a single core compilation process Who runs builds with a single core compilation process? Are we back in 1990? You are hard-pressed to find a CPU with a single core nowadays, even in the cheapest of consumer segments. Why are you fabricating such an unrealistic case?
  - user5994461 6y ago
    The linking phase for C and C++ software is basically linear. Nobody's figured out how to multi thread that since before 1990. It takes hours to build large software (Chrome/Firefox/Qt). By the way, one of the biggest improvements in software performance in the past decade comes from link time optimisations during build (LTO), that's all done during linking and it takes FOREVER.
    - jcelerier 6y ago
      gold has had threading support since its release in 2008. Likewise for lld, which is an order of magnitude faster than gold. From anecdotal experience of the code I am on right now, relinking a few hundred megabytes of .o's takes less than 2 seconds with lld on my 6900k.
    - TazeTSchnitzel 6y ago
      > The linking phase for C and C++ software is basically linear. Depends how many targets you're building. If you have enough memory, you can link several libraries in parallel.
    - rumanator 6y ago
      > The linking phase for C and C++ software is basically linear. Linking is also IO-bound, and already a solved problem in the sense that there are already plenty of solutions that render linking to be a non-issue. It's far from a decent CPU benchmark.
  - Theodores 6y ago
    The key phrase was 'for me'. That 'me' could be working on an existing code base that does a bit more than show a web page and can't be written in flavour of the month toolkits.
daxfohl 6y ago
It also assumes that this important single threaded process's dev team isn't actively working on parallelizing it. And that the primary purpose of the computer will be running this process until its end of life. Both pretty bad assumptions given the minimal benefit and high cost.

Theodores 6y ago

The key words in the parent post are 'for me'. Imagine you have a single core compilation process that takes two minutes that you must run 50 times a day. This can happen. Ten percent brings 12 seconds per compile or ten minutes a day. This might not sound great but it means you can get an extra five compiles done. You can also get increased likelihood that you can remember what you were working on. Therefore the marginal gain in single thread performance is well worth having in this use case. The expense of genuine Intel becomes worth it even if you don't have so many cores.

throwaway_pdp09 6y ago
I have a dual core dev machine. Using -j 2 builds twice as fast (approx 35 mins -> 17 mins). Are current compiles really obligatory single thread? Because I sure would like to prop up intel with my wallet.
- tbrock 6y ago
  Anything JavaScript for example is single threaded for the most part. Also something like linking is typically in parallelized.
  - jatone 6y ago
    thats not the compilation process. that's just javascript. the compilation definitely has parallelism.
    - tbrock 6y ago
      You’d be surprised...
- chitza 6y ago
  Most web development toolchains depend on Node.js, which compiles on a single core.
  - kohtatsu 6y ago
    Node takes advantage of multiple cores. The code is all async by default and that is easy to load onto green threads. This used to be implemented with callback hell, now it's Promises which is actually really cosy (and what Rust is adopting). Random article I found on it: https://medium.com/better-programming/is-node-js-really-single-threaded-7ea59bcc8d64 https://medium.com/better-programming/is-node-js-really-sing...
  - oppositelock 6y ago
    Sure, but you're also running a browser at the same time probably with a ton of tabs open as separate processes. Our computers do quite a lot these days, in parallel, and more cores help. Both AMD and Intel are ridiculously fast! You can't really go wrong with either.
  - jatone 6y ago
    which then shard out to multi processes, still benefitting from more cores being available. I know of at least a few build processes that support that model for node.
- benibela 6y ago
  FreePascal is single threaded But it is also like 10 times faster than other compilers.
jatone 6y ago
fix your compilation process. there are few long running workloads that don't benefit from parallelism.
rumanator 6y ago
> Imagine you have a single core compilation process Who runs builds with a single core compilation process? Are we back in 1990? You are hard-pressed to find a CPU with a single core nowadays, even in the cheapest of consumer segments. Why are you fabricating such an unrealistic case?
- user5994461 6y ago
  The linking phase for C and C++ software is basically linear. Nobody's figured out how to multi thread that since before 1990. It takes hours to build large software (Chrome/Firefox/Qt). By the way, one of the biggest improvements in software performance in the past decade comes from link time optimisations during build (LTO), that's all done during linking and it takes FOREVER.
  - jcelerier 6y ago
    gold has had threading support since its release in 2008. Likewise for lld, which is an order of magnitude faster than gold. From anecdotal experience of the code I am on right now, relinking a few hundred megabytes of .o's takes less than 2 seconds with lld on my 6900k.
  - TazeTSchnitzel 6y ago
    > The linking phase for C and C++ software is basically linear. Depends how many targets you're building. If you have enough memory, you can link several libraries in parallel.
  - rumanator 6y ago
    > The linking phase for C and C++ software is basically linear. Linking is also IO-bound, and already a solved problem in the sense that there are already plenty of solutions that render linking to be a non-issue. It's far from a decent CPU benchmark.
- Theodores 6y ago
  The key phrase was 'for me'. That 'me' could be working on an existing code base that does a bit more than show a web page and can't be written in flavour of the month toolkits.

daxfohl 6y ago

It also assumes that this important single threaded process's dev team isn't actively working on parallelizing it. And that the primary purpose of the computer will be running this process until its end of life. Both pretty bad assumptions given the minimal benefit and high cost.