Limit smoldot's CPU usage to 50%

[tomaka]

This change is there really to avoid a worst case scenario where smoldot has an issue that causes it to never go to sleep.

This will very slightly slow down syncing (verifying the warp sync proof is a pure CPU operation), but avoiding big CPU spikes is more desirable than saving a few milliseconds.

[wirednkod]

Im not sure if this is something that end user should know. Its extension-internal - right?

[tomaka]

It's visible to the user that the usage of their CPU is bounded to 50%

[wirednkod]

There is something print when zombienet tests are running other than uncaught exception - but it is happening after the 140 seconds of the timeout (timeout comes first - prior to log so script exits).
When spawn locally zombienet the actual error print can be found below:

Timeout duration was set to 1.
(node:27030) TimeoutOverflowWarning: 19327215118 does not fit into a 32-bit signed integer.
Timeout duration was set to 1.
(node:27030) TimeoutOverflowWarning: 19327215118 does not fit into a 32-bit signed integer.
Timeout duration was set to 1.
(node:27030) TimeoutOverflowWarning: 19327215118 does not fit into a 32-bit signed integer.
Timeout duration was set to 1.
(node:27030) TimeoutOverflowWarning: 19327215117 does not fit into a 32-bit signed integer.
Timeout duration was set to 1.
(node:27030) TimeoutOverflowWarning: 19327215117 does not fit into a 32-bit signed integer.
Timeout duration was set to 1.
(node:27030) TimeoutOverflowWarning: 19327215117 does not fit into a 32-bit signed integer.
Timeout duration was set to 1.
(node:27030) TimeoutOverflowWarning: 19327215117 does not fit into a 32-bit signed integer.
Timeout duration was set to 1.
(node:27030) TimeoutOverflowWarning: 19327215117 does not fit into a 32-bit signed integer.
Timeout duration was set to 1.
(node:27030) TimeoutOverflowWarning: 19327215117 does not fit into a 32-bit signed integer.
Timeout duration was set to 1.
uncaughtException
Error: Timeout running custom js-script (140)

This sample is from a param of 0.75 (I think) passed to the cpuRateLimit param. Similar results were identified with 0.5, 0.75, 0.85, 0.9 - though with param set to 1 everything works as expected.

With my none-existent rust skills I can only assume that the issue comes either in here or here but again my rust is very bad to say for sure.

[tomaka]

paritytech/smoldot#2188

[tomaka]

paritytech/smoldot#2189

[tomaka]

Despite the bugs in smoldot, it would still be great to figure out why this uncaughtException isn't caught, and properly catch it

[wirednkod]

Despite the bugs in smoldot, it would still be great to figure out why this uncaughtException isn't caught, and properly catch it

Went through zombienet code with @pepoviola . The uncaughtException is actually a console.log as can be seen here and the "error" was the timeout occurred:

Error: Timeout running custom js-script (140)

[pepoviola]

Despite the bugs in smoldot, it would still be great to figure out why this uncaughtException isn't caught, and properly catch it

Went through zombienet code with @pepoviola . The uncaughtException is actually a console.log as can be seen here and the "error" was the timeout occurred:

Error: Timeout running custom js-script (140)

Yes, this will be fixed in the next version of zombienet.
Thanks!