3 Commits (189a0329876329f1d67969a2657ec4b1776fbb24)

Author	SHA1	Message	Date
Péter Szilágyi	054412e335	all: clean up and proerly abstract database access	6 years ago
Felföldi Zsolt	c2003ed63b	les, les/flowcontrol: improved request serving and flow control (#18230) ... This change - implements concurrent LES request serving even for a single peer. - replaces the request cost estimation method with a cost table based on benchmarks which gives much more consistent results. Until now the allowed number of light peers was just a guess which probably contributed a lot to the fluctuating quality of available service. Everything related to request cost is implemented in a single object, the 'cost tracker'. It uses a fixed cost table with a global 'correction factor'. Benchmark code is included and can be run at any time to adapt costs to low-level implementation changes. - reimplements flowcontrol.ClientManager in a cleaner and more efficient way, with added capabilities: There is now control over bandwidth, which allows using the flow control parameters for client prioritization. Target utilization over 100 percent is now supported to model concurrent request processing. Total serving bandwidth is reduced during block processing to prevent database contention. - implements an RPC API for the LES servers allowing server operators to assign priority bandwidth to certain clients and change prioritized status even while the client is connected. The new API is meant for cases where server operators charge for LES using an off-protocol mechanism. - adds a unit test for the new client manager. - adds an end-to-end test using the network simulator that tests bandwidth control functions through the new API.	6 years ago
Felföldi Zsolt	b2ddb1fcbf	les: implement client connection logic (#16899) ... This PR implements les.freeClientPool. It also adds a simulated clock in common/mclock, which enables time-sensitive tests to run quickly and still produce accurate results, and package common/prque which is a generalised variant of prque that enables removing elements other than the top one from the queue. les.freeClientPool implements a client database that limits the connection time of each client and manages accepting/rejecting incoming connections and even kicking out some connected clients. The pool calculates recent usage time for each known client (a value that increases linearly when the client is connected and decreases exponentially when not connected). Clients with lower recent usage are preferred, unknown nodes have the highest priority. Already connected nodes receive a small bias in their favor in order to avoid accepting and instantly kicking out clients. Note: the pool can use any string for client identification. Using signature keys for that purpose would not make sense when being known has a negative value for the client. Currently the LES protocol manager uses IP addresses (without port address) to identify clients.	6 years ago