Web server is extremely slow

[novascreen]

Describe the bug
The web UI shows a blank screen for a very long time because the transfer speed is extremely slow and script tags have no defer attribute on them.

Expected behavior

• web server is fast
• script tags have defer attribute on them so something shows on the screen even if things are slow
• static assets can be cached, ideally forever (use hashed filenames), not no-store

Screenshots

Desktop (please complete the following information):

• Browser: Chrome 136.0.7103.114 on MacOS 15.4.1, Safari on iOS 18.4.1

MyNode hardware (please complete the following information):

• Device: Raspi4
• Version 0.3.36

Additional context
Comparison with transferring the same file using scp:

▶ time scp admin@mynode.local:/var/www/mynode/static/jquery_ui/jquery-ui.js /dev/null
jquery-ui.js                                                     100%  509KB   4.2MB/s   00:00
scp admin@mynode.local:/var/www/mynode/static/jquery_ui/jquery-ui.js /dev/nul  0.02s user 0.03s system 6% cpu 0.803 total

▶ time curl -o /dev/null http://mynode.local/static/jquery_ui/jquery-ui.js
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  508k  100  508k    0     0   6787      0  0:01:16  0:01:16 --:--:--  8906
curl -o /dev/null http://mynode.local/static/jquery_ui/jquery-ui.js  0.01s user 0.03s system 0% cpu 1:16.73 total

At some point I reinstalled the entire MyNode and i'm still having this issue. The fact that I can fetch the file really fast over ssh indicates it's not a network issue and the fact that it also happens from my phone indicates it's not an issue with my laptop either.
There is no difference when using the IP rather than the hostname.

[tehelsper]

How long is a page load taking? On a refresh of the main page, I'm seeing <2s times which makes lots of async requests as well to get system status for each app.

If your xfer is taking 1+ min, I expect something else is happening. I'm seeing <.1s for the same transfer. Maybe try a new SD card? Old cards can have awful read/write times. This is from a RP4.

admin@localhost$ time curl -o /dev/null http://192.168.1.110/static/jquery_ui/jquery-ui.js
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed  
100  508k  100  508k    0     0  12.1M      0 --:--:-- --:--:-- --:--:-- 12.1M 

real    0m0.067s
user    0m0.000s
sys     0m0.016s

[novascreen]

Hm, it does not happen consistently. I will keep investigating when it happens next time.
But when it happens then the page load can take half a minute or even more than a minute.

You could be right in that the SD card could slow things down maybe when other things are happening at the same time 🤔

[novascreen]

Hm i only got this SD-card (SanDisk 32GB Ultra) 8 months ago. I think that's when I set things up fresh because I already had this issue.

[tehelsper]

Is it really SanDisk? That's a good brand. When using USB drives, I've seen off brand ones perform 500x worse than others.

[novascreen]

got it from Amazon, generally think it's legit

[novascreen]

If i do curl from the mynode itself it's fast.
If i do curl from my laptop is when it can be slow.
If i do scp from my laptop it always seems to be fast.

So i guess it's not the python web server itself that's slow.
Changing the port did nothing. I tried serving the server with waitress instead of app.run (dev server), no change.

[novascreen]

Running this for a little while shows a lot of traffic and a lot of lost packets

sudo tcpdump -i eth0 host mynode.local -v

4702 packets captured
12245 packets received by filter
7230 packets dropped by kernel

wondering if this is just the Raspberry Pi being overwhelmed easily. Mempool seems to create quite a bit of constant CPU usage

[tehelsper]

That's a very high packet count. The drop number is just how many packets were missed by the capture, not the device. How long did you run the tcpdump for? Also, it may have been capturing any SSH packets which would throw off results.