Yunhong Gu & Robert Grossman University of Illinois at Chicago UDT Tutorial Yunhong Gu & Robert Grossman University of Illinois at Chicago

Outline Introduction Installation Programming using UDT Performance tuning Conclusion

Introduction UDT – UDP-based Data Transfer Application level End-to-end Bi-directional For shared networks But can be tuned for private networks C++ library

UDT History 2000: SABUL Concept 2001: SABUL version 1.0 2002: dSABUL

Project Online sf.net/projects/udt Source code, documentations, mailing lists, bug reports Tarball release and CVS

Installation Make the C++ source code Tested support hardware IA32, IA64, AMD64, Power PC, SPARC Tested support OS Linux, OS X, Windows, UNIX make -e arch=XXX os=YYY

Post-Installation LD_LIBRARY_PATH Testing using appserver and appclient ./appserver [port] ./appclient <server-addr> <server-port>

Programming using UDT socket-like API UDT:: namespace qualifier UDTERROR

Programming using UDT int client = socket(AF_INET, SOCK_STREAM, 0); connect(client, (sockaddr*)&serv_addr, sizeof(serv_addr)); If (-1 == send(client, data, size, 0)) { //error processing } UDTSOCKET client = UDT::socket(AF_INET, SOCK_STREAM, 0); UDT::connect(client, (sockaddr*)&serv_addr, sizeof(serv_addr)); If (UDTERROR == UDT::send(client, data, size, 0)) { //error processing }

Configuration setsockopt/getsockopt

Overlapped IO int send(   UDTSOCKET,              const char *buf,    int len,   int flags,  int *handle = NULL,  UDT_MEM_ROUTINE routine = NULL ); void (UDT_MEME_ROUTINE*)(char*, int);

Overlapped IO bool getoverlappedresult(   UDTSOCKET u,   const int& handle,   int& progress,   const bool& wait );

Overlapped IO New Data User Buffer Data Protocol Buffer

Performance monitoring Monitor UDT performance statistics Monitor internal UDT parameters Diagnose network and application configurations int perfmon( UDTSOCKET u, TRACEINFO* perf );

Performance monitoring TRACEINFO structure Aggregate information Timestamp, Total send/recv/retrans/loss, etc. Local information (values since last time perfmon was called) Local send/recv/retrans/loss, send/recv rate Instant value RTT, cwnd, ipt, etc.

Performance Tuning UDT buffer size UDP buffer size IO block size Larger is better UDP buffer size SNDBUF << RCVBUF Larger is NOT better IO block size Larger is better, but better less than the UDT buffer size File IO block size: mystery

Thank you!