Comment 4 for bug 2009544

The perf regression is easy to demonstrate using the 'main.py' script attached to this bug, also available here: https://pastebin.ubuntu.com/p/XzV766BpHd/

Some results -

ubuntu@focal-vm:~$ /usr/bin/time -f "\n\nElapsed: %e s" python3 main.py
Distro: Ubuntu 20.04.6 LTS
Python Version: 3.8.10 (default, May 26 2023, 14:05:08)
[GCC 9.4.0]
OpenSSL Version: OpenSSL 1.1.1f 31 Mar 2020
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99

Elapsed: 1.65 s

root@jammy-vm:~# /usr/bin/time -f "\n\nElapsed: %e s" python3 main.py
Distro: Ubuntu 22.04.2 LTS
Python Version: 3.10.6 (main, May 29 2023, 11:10:38) [GCC 11.3.0]
OpenSSL Version: OpenSSL 3.0.2 15 Mar 2022
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99

Elapsed: 5.91 s

Both the above tests were done on a 1core/1G VM. Interestingly, when adding resources it exacerbates the problem, example using 8core/4G VMs (same hardware):

ubuntu@sslfocal-vm1:~$ /usr/bin/time -f "\n\nElapsed: %e s" python3 main.py
Distro: Ubuntu 20.04.6 LTS
Python Version: 3.8.10 (default, May 26 2023, 14:05:08)
[GCC 9.4.0]
OpenSSL Version: OpenSSL 1.1.1f 31 Mar 2020
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99

Elapsed: 1.77 s

ubuntu@ssljammy-vm1:~$ /usr/bin/time -f "\n\nElapsed: %e s" python3 main.py
Distro: Ubuntu 22.04.2 LTS
Python Version: 3.10.6 (main, May 29 2023, 11:10:38) [GCC 11.3.0]
OpenSSL Version: OpenSSL 3.0.2 15 Mar 2022
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99

Elapsed: 12.69 s