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That isn't how hyperthreading works... It's completely dependent on the workload. If your using the CPU core as efficiently as possible, you'd see no benefit f

That isn't how hyperthreading works... It's completely dependent on the workload. If your using the CPU core as efficiently as possible, you'd see no benefit from hyperthreading. If your using it very poorly, you'd see a massive 2~x benefit.

esens 5y ago
When doing C++ compiles and also renders I see a 2x benefit generally. It is rare that I do not see something close to 1.5 to 2x speed ups. That said I did switch from Intel over to an Apple M1 anyway.
- mschuster91 5y ago
  Most compilers are one of the prime cases of inefficient architecture, the worse the larger the project gets. There is an awful lot of time lost waiting on I/O for hundreds to thousands of files (even assuming that there is enough RAM for the OS to cache all the files and metadata, every file that is read has at least three syscall context switches for open/read/close, dito for intermediate writes) and for process creation and destruction. What I would find really, really interesting: a "single-process" compiler that has a global in-RAM cache for all source contents and intermediate outputs and can avoid the overhead of child processes... basically a model like Webpack or Parcel that has an inotify watcher and is constantly running. The JS world had no other choice with NodeJS/npm all but forcing the tooling to adapt to a lot of incredibly small source files, it's time for the "classic" world to adapt.
sidkshatriya 5y ago
> If your using it very poorly, you'd see a massive 2~x benefit. I find this statement tough to agree with. It depends on the kind of work your processors are doing: it is IO heavy work or are you running Math computations? There are other axes basically related to how much work can be done by the current thread while the other thread stalls waiting for data to be fetched (or other non-parallelizable dependencies to be available). So if you're getting a high benefit you shouldn't necessarily feel embarrassed!

esens 5y ago

When doing C++ compiles and also renders I see a 2x benefit generally. It is rare that I do not see something close to 1.5 to 2x speed ups. That said I did switch from Intel over to an Apple M1 anyway.

mschuster91 5y ago
Most compilers are one of the prime cases of inefficient architecture, the worse the larger the project gets. There is an awful lot of time lost waiting on I/O for hundreds to thousands of files (even assuming that there is enough RAM for the OS to cache all the files and metadata, every file that is read has at least three syscall context switches for open/read/close, dito for intermediate writes) and for process creation and destruction. What I would find really, really interesting: a "single-process" compiler that has a global in-RAM cache for all source contents and intermediate outputs and can avoid the overhead of child processes... basically a model like Webpack or Parcel that has an inotify watcher and is constantly running. The JS world had no other choice with NodeJS/npm all but forcing the tooling to adapt to a lot of incredibly small source files, it's time for the "classic" world to adapt.

sidkshatriya 5y ago

> If your using it very poorly, you'd see a massive 2~x benefit. I find this statement tough to agree with. It depends on the kind of work your processors are doing: it is IO heavy work or are you running Math computations? There are other axes basically related to how much work can be done by the current thread while the other thread stalls waiting for data to be fetched (or other non-parallelizable dependencies to be available). So if you're getting a high benefit you shouldn't necessarily feel embarrassed!