HP-UX TCP/IP Performance White Paper, March 2008

4.2.2 Socket Caching for TCP Connections............................................................................20
4.2.3 Tuning tcphashsz.......................................................................................................21
4.2.4 Tuning the listen queue limit.........................................................................................22
4.2.5 Using MSG_EOF flag for TCP Applications....................................................................24
4.3 Tuning Servers in Wireless Networks..................................................................................25
4.3.1 Smoothed RTO Algorithm............................................................................................25
4.3.2 Forward-Retransmission Timeout (F-RTO)........................................................................25
5 Tuning Applications Using Programmatic Interfaces .....................................................................27
5.1 sendfile() .......................................................................................................................27
5.2 Polling Events.................................................................................................................27
5.3 send() and recv() Socket Buffers.........................................................................................28
5.3.1 Data Buffering in Sockets............................................................................................28
5.3.2 Controlling Socket Buffer Limits ....................................................................................28
5.3.3 System Socket Buffer Tunables.....................................................................................29
5.4 Effective use of the listen backlog value...............................................................................29
6 Monitoring Network Performance.............................................................................................31
6.1 Monitoring network statistics.............................................................................................31
6.1.1 Monitoring TCP connections with netstat –an..................................................................32
6.1.2 Monitoring protocol statistics with netstat -p....................................................................32
6.1.3 Monitoring link level statistics with lanadmin ..................................................................34
6.2 Monitoring System Resource Utilization...............................................................................35
6.2.1 Monitoring CPU Utilization Using Glance......................................................................35
6.2.2 Monitoring CPU statistics using Caliper.........................................................................36
6.2.3 Monitoring Memory Utilization using Glance:.................................................................37
6.2.4 Monitoring Memory utilization using vmstat ..................................................................38
6.2.5 Monitoring Cache Miss Latency...................................................................................38
6.2.6 Monitoring other resources..........................................................................................38
6.3 Measuring Network Throughput ........................................................................................38
6.3.1 Measuring Throughput with Netperf Bulk Data transfer.....................................................39
6.3.2 Measuring Transaction Rate with Netperf request/response:.............................................39
6.3.3 Key issues for throughput with Netperf traffic..................................................................40
6.4 Additional Monitoring Tools..............................................................................................40
Appendix A: Annotated output of netstat –s (TCP, UDP, IP, ICMP)..........................................................41
Appendix B: Annotated output of ndd –h and discussions of the TCP/IP tunables .....................................53
Table 1: Summary of TCP/IP Tunables..............................................................................................81
Table 2: Operating System Support for TCP/IP Tunables......................................................................85
Revision History............................................................................................................................89