RPC_CWNDSCALE
#define RPC_INITCWND RPC_CWNDSCALE
xprt->cong += RPC_CWNDSCALE;
xprt->cong -= RPC_CWNDSCALE;
cwnd += (RPC_CWNDSCALE * RPC_CWNDSCALE + (cwnd >> 1)) / cwnd;
if (cwnd < RPC_CWNDSCALE)
cwnd = RPC_CWNDSCALE;