usrp: Change default number of data frames for X300

Change the default number of frames so that it works well when using
offload threads, including DPDK. This matches the default number of
frames in mpmd.

1 files changed, 20 insertions, 16 deletions

diff --git a/host/lib/usrp/x300/x300_eth_mgr.cpp b/host/lib/usrp/x300/x300_eth_mgr.cpp
index 02f9abe0f..5153af671 100644
--- a/host/lib/usrp/x300/x300_eth_mgr.cpp
+++ b/host/lib/usrp/x300/x300_eth_mgr.cpp
@@ -52,14 +52,18 @@ constexpr size_t XGE_DATA_FRAME_RECV_SIZE = 8000;
 constexpr size_t GE_DATA_FRAME_SEND_SIZE  = 1472;
 constexpr size_t GE_DATA_FRAME_RECV_SIZE  = 1472;
 constexpr size_t ETH_MSG_NUM_FRAMES       = 64;
-constexpr size_t ETH_DATA_NUM_FRAMES      = 32;
-constexpr size_t ETH_MSG_FRAME_SIZE       = uhd::transport::udp_simple::mtu; // bytes
-constexpr size_t MAX_RATE_10GIGE          = (size_t)( // bytes/s
+
+// Default for num data frames is set to a value that will work well when send
+// or recv offload is enabled, or when using DPDK.
+constexpr size_t ETH_DATA_NUM_FRAMES = 32;
+
+constexpr size_t ETH_MSG_FRAME_SIZE = uhd::transport::udp_simple::mtu; // bytes
+constexpr size_t MAX_RATE_10GIGE    = (size_t)( // bytes/s
     10e9 / 8 * // wire speed multiplied by percentage of packets that is sample data
     (float(x300::DATA_FRAME_MAX_SIZE - CHDR_MAX_LEN_HDR)
         / float(x300::DATA_FRAME_MAX_SIZE
                 + 8 /* UDP header */ + 20 /* Ethernet header length */)));
-constexpr size_t MAX_RATE_1GIGE           = (size_t)( // bytes/s
+constexpr size_t MAX_RATE_1GIGE     = (size_t)( // bytes/s
     10e9 / 8 * // wire speed multiplied by percentage of packets that is sample data
     (float(GE_DATA_FRAME_RECV_SIZE - CHDR_MAX_LEN_HDR)
         / float(GE_DATA_FRAME_RECV_SIZE
@@ -196,7 +200,7 @@ eth_manager::eth_manager(
     // Once we read the EEPROM, we use it to map IP to its interface
     // In discover_eth(), we'll check and enable the other IP address, if given
     x300_eth_conn_t init;
-    init.addr = args.get_first_addr();
+    init.addr      = args.get_first_addr();
     auto device_id = allocate_device_id();
     _local_device_ids.push_back(device_id);
     eth_conns[device_id] = init;
@@ -237,18 +241,16 @@ both_links_t eth_manager::get_links(link_type_t link_type,
     // Buffering is done in the socket buffers, so size them relative to
     // the link rate
     link_params_t default_link_params;
-    // There is no need for more than 1 send and recv frame since the
-    // buffering is done in the socket buffers
-    default_link_params.num_send_frames = 1; // or 2?
-    default_link_params.num_recv_frames = 2;
+    default_link_params.num_send_frames = ETH_DATA_NUM_FRAMES;
+    default_link_params.num_recv_frames = ETH_DATA_NUM_FRAMES;
     default_link_params.send_frame_size = conn.link_rate == MAX_RATE_1GIGE
                                               ? GE_DATA_FRAME_SEND_SIZE
                                               : XGE_DATA_FRAME_SEND_SIZE;
     default_link_params.recv_frame_size = conn.link_rate == MAX_RATE_1GIGE
                                               ? GE_DATA_FRAME_RECV_SIZE
                                               : XGE_DATA_FRAME_RECV_SIZE;
-    default_link_params.send_buff_size  = conn.link_rate / 50;
-    default_link_params.recv_buff_size  = std::max(conn.link_rate / 50,
+    default_link_params.send_buff_size = conn.link_rate / 50;
+    default_link_params.recv_buff_size = std::max(conn.link_rate / 50,
         ETH_MSG_NUM_FRAMES * ETH_MSG_FRAME_SIZE); // enough to hold greater of 20 ms or
                                                   // number of msg frames
 
@@ -260,8 +262,10 @@ both_links_t eth_manager::get_links(link_type_t link_type,
         link_args);
 
     // Enforce a minimum bound of the number of receive and send frames.
-    link_params.num_send_frames = std::max(uhd::rfnoc::MIN_NUM_FRAMES, link_params.num_send_frames);
-    link_params.num_recv_frames = std::max(uhd::rfnoc::MIN_NUM_FRAMES, link_params.num_recv_frames);
+    link_params.num_send_frames =
+        std::max(uhd::rfnoc::MIN_NUM_FRAMES, link_params.num_send_frames);
+    link_params.num_recv_frames =
+        std::max(uhd::rfnoc::MIN_NUM_FRAMES, link_params.num_recv_frames);
 
     if (_args.get_use_dpdk()) {
 #ifdef HAVE_DPDK
@@ -338,8 +342,8 @@ void eth_manager::init_link(
 
         _max_frame_sizes = pri_frame_sizes;
         if (_local_device_ids.size() > 1) {
-            frame_size_t sec_frame_sizes =
-                determine_max_frame_size(eth_conns.at(_local_device_ids.at(1)).addr, req_max_frame_size);
+            frame_size_t sec_frame_sizes = determine_max_frame_size(
+                eth_conns.at(_local_device_ids.at(1)).addr, req_max_frame_size);
 
             // Choose the minimum of the max frame sizes
             // to ensure we don't exceed any one of the links' MTU
@@ -382,7 +386,7 @@ void eth_manager::init_link(
     // Check actual frame sizes against detected frame sizes, and print
     // warnings if they don't match
     for (auto conn_pair : eth_conns) {
-        auto conn = conn_pair.second;
+        auto conn                  = conn_pair.second;
         size_t rec_send_frame_size = conn.link_rate == MAX_RATE_1GIGE
                                          ? GE_DATA_FRAME_SEND_SIZE
                                          : XGE_DATA_FRAME_SEND_SIZE;