Please eliminating the allocations introduced by v1.38.1

[viciousstar]

Is your feature request related to a problem? Please describe.
Tokio version 1.38.1 introducing excessive memory allocations .
In version 1.38, our memory allocation QPS was at 1k/s, but after upgrading to 1.38.1, it became 3k/s. Currently, we are not sure if this has any impact on the overall performance of our application. our application is a proxy of redis, the complexity of memory allocation QPS may increase to n from 1.

Describe the solution you'd like
eliminating the allocations introduced from v1.38.1

Describe alternatives you've considered
No

Additional context

[Darksonn]

One option could be to wrap the wheels in an RwLock. That way, we can lock the write lock and access the mutex contents with Mutex::get_mut. All other accesses could use a read lock to avoid blocking each other.

[viciousstar]

If I do not want to use v1.38.1, which version should we use? v1.37?

[Darksonn]

You can use 1.37.0.

[viciousstar]

In the scenario of a total request of 30,000 requests per second, the number of memory allocations per second has risen from 6k to 18k.

[tglane]

I'd like to work on this. Will open a PR soon.

[hawkw]

The approach described by @Darksonn in #6757 (comment) seems like the right solution to me, at least for now.