Slow Quic tests on Linux

[bentoi]

On Linux, the Quic tests take more than 30s to complete. They used to complete much faster and they still do on Windows.

I'm seeing this since I switched to Ubuntu 22.04.

[bentoi]

I don't have this issue on Debian... I suspect this has something to do with the use of openssl 3.x for msquic.

libmsquic is not available yet for Debian 12 so I haven't been able to try it out.

[bentoi]

See https://github.com/zeroc-ice/dist-utils/issues/238 for Debian 12.

[bentoi]

There are many reports of serious performance issues with OpenSSL 3, in particular with multithreaded code.

See:

• 3.0 Performance problems openssl/openssl#17627
• Massive performance degradation in OpenSsl 3.0 if used in a heavy multi threaded server application openssl/openssl#17064

If I patch the protocol tests to run with Quic I'm getting all kind of timeouts.

A bandaid fix is to reduce the number of workers:

Worker Count	Time to run the Quic tests
1	39 s
2	25 s
3	26 s
4	47 s

Looks a worker count of 2 provides the "best" performances 😳.

[bentoi]

I'm moving to 0.2. I keep open to see if we can remove #3484 in 0.2.