3 ms·

Redis 6 has already supported multiple threads for IO. The memory storage engine is still inside a single thread but I think it's fine.

lrem 5y ago
Do you mean that a single CPU can saturate the throughput of a machine's RAM? That's a bit surprising, given that current crop of Intel CPUs does non uniform memory access. Or, is that bandwidth so much above any I/O that it doesn't matter?
- doyoubi 5y ago
  Nop. It's that a better solution would still be using multiple Redis instances on each physical server. Trying to support multi-threads in the storage engine requires complex synchronization implementation. Sharing nothing between each small instance achieves higher performance and is a lot simpler. Also, FULL SYNC between masters and replicas can be uncontrollable. And smaller memory size for each instance alleviates the performance impact from FULL SYNC.
  - ohthehugemanate 5y ago
    not to mention, multiple instances follows the indistry direction in horizontal scalability. Common advice when building for k8s style cloud environments is to target single core, n instances, to maximize scaling flexibility and atomicity.
throwaway81523 5y ago
There is a parallel but less fancy reimplementation of Redis called Pedis: https://github.com/fastio/1store https://github.com/fastio/1store It's built using Seastar, which is sort of an ugh but cool unholy marriage of node.js and C++14 with an event loop per thread, and message passing between threads. It predates C++20 coroutines I guess, so you pass callbacks around like in Node using C++ lambdas. Maybe they have updated that by now. They have also done a version of memcached using DPDK. I don't see a Pedis one, but check out their memcached one (scroll down): http://seastar.io/ http://seastar.io/
- doyoubi 5y ago
  Cool! Thanks for sharing.
- EdwardDiego 5y ago
  Wow that's a product name horribly prone to typo/auto-correct awkwardness.
  - rubyist5eva 5y ago
    At first I was like, “heh, parallel redis so pedis”…then I said it out loud and I was like….oh my
- derefr 5y ago
  > It's built using Seastar, which is sort of an ugh but cool unholy marriage of node.js and C++14 with an event loop per thread, and message passing between threads. It predates C++20 coroutines I guess, so you pass callbacks around like in Node using C++ lambdas. Maybe they have updated that by now. That seems like a lot of work just to badly recreate Erlang. (Which, yes, doesn’t let you define your own native data structures in-and-of-itself — but there’s always NIFs, e.g. https://blog.discord.com/using-rust-to-scale-elixir-for-11-million-concurrent-users-c6f19fc029d3 https://blog.discord.com/using-rust-to-scale-elixir-for-11-m....)

lrem 5y ago

Do you mean that a single CPU can saturate the throughput of a machine's RAM? That's a bit surprising, given that current crop of Intel CPUs does non uniform memory access. Or, is that bandwidth so much above any I/O that it doesn't matter?

doyoubi 5y ago
Nop. It's that a better solution would still be using multiple Redis instances on each physical server. Trying to support multi-threads in the storage engine requires complex synchronization implementation. Sharing nothing between each small instance achieves higher performance and is a lot simpler. Also, FULL SYNC between masters and replicas can be uncontrollable. And smaller memory size for each instance alleviates the performance impact from FULL SYNC.
- ohthehugemanate 5y ago
  not to mention, multiple instances follows the indistry direction in horizontal scalability. Common advice when building for k8s style cloud environments is to target single core, n instances, to maximize scaling flexibility and atomicity.

throwaway81523 5y ago

There is a parallel but less fancy reimplementation of Redis called Pedis: https://github.com/fastio/1store https://github.com/fastio/1store It's built using Seastar, which is sort of an ugh but cool unholy marriage of node.js and C++14 with an event loop per thread, and message passing between threads. It predates C++20 coroutines I guess, so you pass callbacks around like in Node using C++ lambdas. Maybe they have updated that by now. They have also done a version of memcached using DPDK. I don't see a Pedis one, but check out their memcached one (scroll down): http://seastar.io/ http://seastar.io/

doyoubi 5y ago
Cool! Thanks for sharing.
EdwardDiego 5y ago
Wow that's a product name horribly prone to typo/auto-correct awkwardness.
- rubyist5eva 5y ago
  At first I was like, “heh, parallel redis so pedis”…then I said it out loud and I was like….oh my
derefr 5y ago
> It's built using Seastar, which is sort of an ugh but cool unholy marriage of node.js and C++14 with an event loop per thread, and message passing between threads. It predates C++20 coroutines I guess, so you pass callbacks around like in Node using C++ lambdas. Maybe they have updated that by now. That seems like a lot of work just to badly recreate Erlang. (Which, yes, doesn’t let you define your own native data structures in-and-of-itself — but there’s always NIFs, e.g. https://blog.discord.com/using-rust-to-scale-elixir-for-11-million-concurrent-users-c6f19fc029d3 https://blog.discord.com/using-rust-to-scale-elixir-for-11-m....)