5 ms·

Agreed it's simpler, but using NIO with one OS thread per core also has it's benefits. The context switch (how ever small) will cause latency when this solutio

by bullen 5y ago

Agreed it's simpler, but using NIO with one OS thread per core also has it's benefits. The context switch (how ever small) will cause latency when this solution is at saturation. I think they should write four tests: fiber, NIO and each with userspace networking (no kernel copying network memory) and compare them. Why Oracle is stalling removing the kernel for Java networking is surprising to me, they allready have a VM.

pron 5y ago
https://github.com/ebarlas/project-loom-comparison https://github.com/ebarlas/project-loom-comparison
- vlovich123 5y ago
  Shouldn’t you be able to send authorization and authentication requests in parallel in the async and virtual threads cases?
  - threeseed 5y ago
    It is just an example so they could do anything. But in the real world it is common to need information from the authorization stage to use in the authentication stage. For example you may have a user login with an email address/password which you then pass to an LDAP server in order to get a userId. This userId is then used in a database to determine with objects/groups they have access to.
    - vlovich123 5y ago
      A lower latency design would be for the authorization service to be able to work with either. That way those requests could be done in parallel to reduce latency.
- bullen 5y ago
  Thx, I'm missing bandwidth and latency in those graphs.
blibble 5y ago
there's still a context switch with NIO, you're just doing it manually
- bullen 5y ago
  The context switches in NIO is between fewer threads, you just need one per core. Memory contention is also playing into this. The benchmark they made is asking the question in a way that it leans into the answer they need, just like 99% of all human activity it's biased.
  - blibble 5y ago
    you're missing the point and taking "context switch" literally with NIO you are still managing the stack, just yourself instead of letting the operating system do it for you it is still a "context switch", just done in your code instead of the OS and that's not free (and likely more expensive than saving and restoring a set of registers)

by bullen 5y ago

pron 5y ago

https://github.com/ebarlas/project-loom-comparison https://github.com/ebarlas/project-loom-comparison

vlovich123 5y ago
Shouldn’t you be able to send authorization and authentication requests in parallel in the async and virtual threads cases?
- threeseed 5y ago
  It is just an example so they could do anything. But in the real world it is common to need information from the authorization stage to use in the authentication stage. For example you may have a user login with an email address/password which you then pass to an LDAP server in order to get a userId. This userId is then used in a database to determine with objects/groups they have access to.
  - vlovich123 5y ago
    A lower latency design would be for the authorization service to be able to work with either. That way those requests could be done in parallel to reduce latency.
bullen 5y ago
Thx, I'm missing bandwidth and latency in those graphs.

blibble 5y ago

there's still a context switch with NIO, you're just doing it manually

bullen 5y ago
The context switches in NIO is between fewer threads, you just need one per core. Memory contention is also playing into this. The benchmark they made is asking the question in a way that it leans into the answer they need, just like 99% of all human activity it's biased.
- blibble 5y ago
  you're missing the point and taking "context switch" literally with NIO you are still managing the stack, just yourself instead of letting the operating system do it for you it is still a "context switch", just done in your code instead of the OS and that's not free (and likely more expensive than saving and restoring a set of registers)