Performance accessing WSL2 instance via localhost is dismal

[pds2208]

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Please fill out the below information:

• Your Windows build number: (Type ver at a Windows Command Prompt)

10.0.19041.173

• What you're doing and what's happening: (Copy&paste the full set of specific command-line steps necessary to reproduce the behavior, and their output. Include screen shots if that helps demonstrate the problem.)

Doing a large number of network request to a WSL 2 instance using 'localhost' is around > 10 times slower than access the instance via its IP address. For example, a large number of inserts into a database running either directly in WSL or via Docker. See https://www.reddit.com/r/bashonubuntuonwindows/comments/fxe3wu/postgres_in_wsl2_performance/

• What's wrong / what should be happening instead:

There should be no performance difference between localhost and the WSL2 instance IP address

• Strace of the failing command, if applicable: (If some_command is failing, then run strace -o some_command.strace -f some_command some_args, and link the contents of some_command.strace in a gist here).

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[therealkenc]

/dupe #4946 (with side order of #4901)

[ghost]

Hi! We've identified this issue as a duplicate of another one that already exists in this repository. This specific instance is being closed in favor of tracking the concern over on the referenced thread.

Thanks for your report!

[pds2208]

Okay. I guess down you can now narrow it down to something to do with using localhost rather than the IP address. Hope it helps and hope it gets fixed soon.

[eldiablolives]

@pds2208 you are right, when accessing localhost be it through alias or IP address, it is dead slow, accessing through network is fast, so if you do ifconfig in WSL, find out your IP address then access through that IP address then it's all good. Problem with that 1) I've got to serve apps on 0.0.0.0 2) I have to look it up on DHCP change.