RPC performance issue

[Medha Rane]

Hi,

We have a RPC performance problem on HPUX 11.31 server where our application takes considerable time to send data to client systems. Application trace logs show that server side svc_sendreply() takes about 4 seconds to send across less than 100 kB of data. The thick-client application runs on Windows systems.

The same application on HPUX 11.11 works as expected for the same data and shows no performance drop.

IPFilter is disabled on the 11.31 server. Are there some additional features on 11.31 that monitors RPC communication that could slow down the process? Is there anything we can check on the server OS (maybe network interface settings)?

Additional information:
With Wireshark on Windows we captured packets and observed that the datasize of packets from server starts initially at 1260 then reduces to sizes of 180-200 bytes. The start to end of the packets for a chunk of data from server took approximately 0.22 seconds. For large set Result data this adds up to the total time required for data transmission.
Similar packet capture of HPUX 11.11 system, showed a consistent packet size of 1460.


- IPFilter has been disabled to avoid RPC filtering.

- With lanadmin played with combinations of the settings :
auto-negotiation - on/off
card speed – 100Mbps full/half, 1000Mbps full/half
TCP checksum offloading – on/off
Reducing MTU size from maximum 1500 bits

- Updating socket buffer size in application code to 8192 from default OS set value.

None of the above helped in the case.

Thanks

[Shibin_2]

Are there any messages in the /var/adm/syslog/syslog.log file pertaining to RPC?

[Medha Rane]

syslog.log has inetd entries for adding rpc service and vmunix entries RPC initialization entries only.

No other message for RPC.

[rick jones]

Take a tusc trace to see what system calls the svc_sendreply() is making, and do the same on the 11.11 system if you can. If you look at your packet capture, do you ever see more than one of those small packets on the wire at one time or are they always separated by an ACK from the receiver?