Table of Contents
BestPractice
Memory Management
KCP use malloc/free
for memory management, user can use ikcp_allocator
to use other solution. Remember to setup it at the first line of main()
:
ikcp_allocator(my_new_malloc, my_new_free);
Reduce Redundancy for FEC
As concrete transport is specified by application, which integrate KCP(For more information, read Usage). When FEC is used by application-level, it may contains some redundancy packets. User should feed KCP(by ikcp_input
) by the packets without redundancy, that is, if received packets p0,p1,p0,p2
, user should feed KCP p0,p1,p2
, rather than p0,p1,p0,p2
, the duplicated p0
should never feed to KCP, or there maybe more ACK packets.
For example, the FEC in application use triple redundancy:
Fn = (Pn, Pn-1, Pn-2)
P0 = (0, X, X)
P1 = (1, 0, X)
P2 = (2, 1, 0)
P3 = (3, 2, 1)
The recever can recover previous two packet from one packet. User should reduce the duplicated packets then feed to KCP.
Advance Update
For server-side application, for example linux application server, select
or epoll
is often used in non-blocking
async
architecture, to serve over 10k
clients. For these use scenarios, there are usually huge connections(>3k) to serve, it may cause performance issue when use ikcp_update
for each connection to upddate, user should better use ikcp_check
to replace ikcp_update
. Unlike ikcp_update
to update KCP every N ms, ikcp_check
tells us the exactly time to update the KCP(Only need to update when called ikcp_send
or ikcp_input
).
For example, user can use ikcp_udpate
at the first time, then use ikcp_check
to get the next time to call ikcp_update
. It's reported that the CPU usage descreate form 60% to 15% when use ikcp_check
.