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WSL2 and still waiting...

Disclaimer on behalf of Microsoft: The findings reported here are based on a very fresh version of Windows 10 made available to "insiders" (like me) only two days ago. All conclusions should therefore be seen as subject to change and not applying for any Windows 10 version for professional use.

Less than one month ago, I wrote this article, highlighting the fact that even though Microsoft strives to be able to execute GNU/Linux software on Windows 10 as well on any native GNU/Linux installation, this objective has not yet been reached.

Today I conclude that even though progress has been made in some areas, other areas work less convincingly.

This Microsoft statement recently announced improvements in both Docker performance as well as the brand new Windows Subsystem for Linux, version 2 (WSL2). Today (June 14, 2019), I conclude that

  1. Docker performance has perhaps slightly improved.
  2. WSL2 now has the extremely useful ability to run GNU/Linux binaries without any need to recompile.
  3. WSL2 has an issue with the NTFS file system. It is probably a bug which can be fixed.
  4. WSL2 runtime performance for a 12-core, CPU-intensive "number-crunching" job definitely does not live up to expectations (see below).

What is new with Windows Subsystem for Linux, version 2?

Item 2 on the above list is an important system design target which appears to have been met. Don't get me wrong on that.

The root file system now resides on a virtual disk file. On WSL1, the root file system resided as an ordinary file system on the Windows system drive.

Otherwise, WSL2 looks like WSL1. Handling - such as resetting the root file system - is very similar.

Details about how the performance study was done

Please consult my previous article. You may also ask me some questions.

Results of the performance study

As before, the runtimes quoted below apply for the central part of an OpenFOAM simulation. Small deviations in the Ubuntu results can be attributed to a minor hardware change (to allow for triple-booting).

Previous performance results (WSL1 performance was originally misquoted):

Native Ubuntu: 16 minutes and 6 seconds

Docker on Ubuntu: 16 minutes and 17 seconds

Docker on Windows: 31 minutes and 51 seconds

WSL1 (on Windows): 31 minutes and 49 seconds (has been erroneously quoted as 10 minutes shorter)

New performance results (June 14, 2019):

Native Ubuntu: 16 minutes and 5 seconds

Docker on Ubuntu: 16 minutes and 13 seconds

Docker on Windows: 29 minutes and 19 seconds

WSL2 (on Windows): 29 minutes and 53 seconds

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