From f9f7b34d546a79bec55cf9d0e48ef3876f0f67d7 Mon Sep 17 00:00:00 2001 From: Michael West Date: Wed, 13 Feb 2019 16:29:18 -0800 Subject: RFNoC: Disable FC ACK packets for lossless links FC ACK packets are unnecessary on lossless links and degrade overall performance. This change disables those packets on all lossless links. Signed-off-by: Michael West --- host/lib/rfnoc/graph_impl.cpp | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) (limited to 'host/lib/rfnoc/graph_impl.cpp') diff --git a/host/lib/rfnoc/graph_impl.cpp b/host/lib/rfnoc/graph_impl.cpp index 989bcb0c4..326e9205d 100644 --- a/host/lib/rfnoc/graph_impl.cpp +++ b/host/lib/rfnoc/graph_impl.cpp @@ -120,17 +120,17 @@ void graph_impl::connect(const block_id_t& src_block, % dst->get_block_id().get() % (dst->get_fifo_size(dst_block_port) / 1024) % (pkt_size / 1024) % src->get_block_id().get())); } + const bool same_xbar = sid.get_src_addr() == sid.get_dst_addr(); src->configure_flow_control_out(true, /* enable output */ + same_xbar, // Lossless link if on same crossbar buf_size_bytes, 0, /* no packet limit. We need to revisit this at some point. */ src_block_port); // On the same crossbar, use lots of FC packets - size_t bytes_per_response = - buf_size_bytes / uhd::rfnoc::DEFAULT_FC_XBAR_RESPONSE_FREQ; // Over the network, use less or we'd flood the transport - if (sid.get_src_addr() != sid.get_dst_addr()) { - bytes_per_response = buf_size_bytes / uhd::rfnoc::DEFAULT_FC_TX_RESPONSE_FREQ; - } + const size_t bytes_per_response = + same_xbar ? buf_size_bytes / uhd::rfnoc::DEFAULT_FC_XBAR_RESPONSE_FREQ + : buf_size_bytes / uhd::rfnoc::DEFAULT_FC_TX_RESPONSE_FREQ; UHD_ASSERT_THROW(bytes_per_response != 0); dst->configure_flow_control_in(bytes_per_response, dst_block_port); @@ -189,7 +189,12 @@ void graph_impl::connect_src(const block_id_t& src_block, % (buf_size_dst_bytes / 1024) % (pkt_size / 1024) % src->get_block_id().get())); } - src->configure_flow_control_out(buf_size_pkts, src_block_port); + + src->configure_flow_control_out(true, /* enable output */ + (dst_sid.get_src_addr() == dst_sid.get_dst_addr()), + buf_size_dst_bytes, + 0, /* no packet limit. We need to revisit this at some point. */ + src_block_port); } void graph_impl::connect_sink( -- cgit v1.2.3