[Async-sig] Feedback, loop.load() function

[Chris Jerdonek]

On Sun, Aug 6, 2017 at 3:57 PM, Pau Freixes <pfreixes at gmail.com> wrote:
> Hi guys,
>
> I would appreciate any feedback about the idea of implementing a new
> load function to ask about how saturated is your reactor.

Hi,

Would it be possible for you to rephrase what you've done in terms of
asyncio terminology? From what I can tell, "reactor" isn't a term used
in the asyncio docs or code base. It might also improve the
readability of your asyncio patch to use asyncio terminology in the
code comments, doc strings, etc.

--Chris


>
> I have a proof of concept [1] of how the load function might be
> implemented in the Asyncio python loop.
>
> The idea is to provide a method that can be used to ask about the load
> of the reactor in a specific time, this implementation returns the
> load taking into account the last 60 seconds but it can easily return
> the 5m and 15minutes ones u others.
>
> This method can help services built on to of Asyncio to implement back
> pressure mechanisms that take into account a metric coming from the
> loop, instead of inferring the load using other metrics provided by
> external agents such as the CPU, load average u others.
>
> Nowadays exists some alternatives for other languages that address
> this situation using the lag of a scheduler callback, produced by
> saturated reactors. The most known implementation is toobusy [2] a
> nodejs implementation.
>
> IMHO the solution provided by tobusy has a strong dependency with the
> hardware needing to tune the maximum lag allowed in terms of
> milliseconds [3]. in the POF presented the user can use an exact value
> meaning the percentage of the load, perhaps 0.9
>
> Any comment would be appreciated.
>
> [1] https://github.com/pfreixes/cpython/commit/5fef3cae043abd62165ce40b181286e18f5fb19c
> [2] https://www.npmjs.com/package/toobusy
> [3] https://www.npmjs.com/package/toobusy#tunable-parameters
> --
> --pau
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