generateBid - query time left

[jonasz]

Hi,

During the last FLEDGE call we discussed potential approaches to learning how much time is left from within generateBid before a timeout occurs.

As I understand, exposing an accurate timer would introduce certain privacy risks.

One idea proposed was to allow to query whether "at least 3ms is left". An extension of this idea would be to provide a function getApproxTimeLeft(), which returns a lower bound on time left. A potential implementation could return time left minus some random number, or time left rounded down to a multiple of 5ms. Even a very limited version, where we can learn whether there's "at least 1", "at least 5", "at least 25" would be quite useful already.

I'd be curious to hear if that sounds feasible to you.

Best regards,
Jonasz

[brusshamilton]

Something like that may be feasible (with appropriate noising and rate limiting), but I'm curious if another solution could fit this use case.

In the 2022-02-02 FLEDGE call it was suggested FLEDGE allow multiple calls to reportLoss in generateBid and just use the last one. Would something similar to this where FLEDGE offers a setBid function to specify what bid to use if the worklet times out before returning also apply to your use case?

Part of my concern is that given the wide range of performance for devices that may run FLEDGE, the time left may not be a good measure for how much more work could be done.

[jonasz]

Hi @brusshamilton ,

Such a setBid sounds great, indeed it should be more reliable than getApproxTimeLeft. Thanks for proposing this!

To expand a bit, I think in future it could be useful to have both setBid and getApproxTimeLeft, as they provide somewhat different functionalities ("let's make sure I don't lose my result so far" vs "let's decide which computation to perform next - heavy or lightweight"). That said, if we were to choose now, we'd definitely go with setBid and perhaps come back to discussing getApproxTimeLeft sometime in future.