APAR status
Closed as canceled.
Error description
!!! NO LONGER MAINTAINED AS OF 3/26/08 !!! REFERENCE THE FOLLOWING URL FOR INFORMATION REGARDING z/OS COMMUNICATIONS SERVER PERFORMANCE: http://www.ibm.com/support/docview.wss?rs=852&uid=swg27005524 . . KEYWORDS: TCPIPINFO PERFORMANCEX 5655HAL00 R340 R350 R50A OS390IP TCPIP TCP/IP TCP/IP Performance Checklist ============================ Here is a quick summary of a performance checklist, which may help in confirming performance settings for your environment. * MVS dispatching priority of TCP/IP, FTP or other servers: Recommendation: Set TCPIP equal to VTAM or 1 lower than VTAM. For other started tasks such as FTP, ADSM: slightly lower than TCPIP task. * Make sure client/server TCP Window size is set to allowed maximum. Recommendation: Set the TCP window size on MVS to the allowed maximum by setting TCPRCVBUFRSIZE to 32K or larger and, if client workstation permits, use 65535 as the client window size. If the installation is storage constrained, however, use the default TCPRCVBUFRSIZE of 16K. **********NOTE WINDOWS NT USERS************ Windows NT defaults send window size to 8K(8192) update parm DefaultSendWindow in order to increase the send window. Users of other TCPIP stacks need to refer to Vendor to determine how to increase send window size. . Note: RFC 1323 which supports larger than 64K-1 TCP window size is available in V2R7. . * Make sure client and server MTU/packet size are equal. Follow the recommendations given in the PROFILE.TCPIP section of this information APAR. * 3172: Make sure Delay timer and Max. response length are set correctly for each LAN adapter: Recommendation: Delay Timer = 10 ms, Max. response length = 500 bytes * 2216: Make sure Blk timer and Ack length are set correctly for each LCS or MPC+ definition: Recommendation: Blk Timer = 5 ms, Ack Length = 10 bytes * FTP: Use large data set blocksizes on MVS. Recommendation: Data set blocksize = 1/2 DASD track. Follow the recommendations discussed in the FTP DATA section of this information APAR. * Sockets: Use large msg sizes (> 1 KB) for better performance. * PTF's: Make sure you have latest TCP/IP Performance PTF's. We continually improve performance of OS/390 releases and it is recommended to keep track of PSP buckets for important PTFs. * Make sure TCP/IP and all other traces are turned off for optimal performance. Trace activity does create an extra processing overhead. * CS/39 Performance Web Page References: http://www.software.ibm.com/network/commserver/library /whitepapers/csos390.html http://www.software.ibm.com/enetwork/commserver/library /whitepapers/white_csos390ip.html . CAPACITY PLANNING ***************** The information provided here will provide you the methodology for capacity planning for Telnet and FTP. . CAPACITY PLANNING (TELNET TN3270): In order to determine the capacity planning requirements, one needs to determine the CPU cost of performing a transaction of interest on a specific machine type. For example, we have used the Telnet TN3270 workload where 100 bytes of data is sent from Telnet client to Echo application running on OS/390 Telnet TN3270 Server and 800 bytes of data is sent by Echo application as a reply to Telnet client. From our benchmarks we have derived CPU cost in terms of milliseconds per Telnet TN3270 transaction using IBM 9672-RX6 (4 CP LPAR). . - 0.59 msec/tran (For number of users 4,000 to 16,000) - 0.65 msec/tran (For number of users 16,001 to 32,000) - 0.71 msec/tran (For number of users 32,001 to 64,000) . Above CPU numbers include TCPIP, VTAM and Echo application. For example, we want to determine the capacity planning requirements for 4000 users, each doing 6 transactions per user per minute on a IBM 9672-RX6 (4 CP LPAR). . Total CPU Requirements: # trans/user x # users x CPU secs/tran CPU secs --------------------------------------- = --------- # of Elap secs Elap secs . Example: CS/390 R5, 4000 users, 6 tr/min/user . 6 tr/u x 4000u x 0.00059 CPU secs/tr cpu sec ------------------------------------- = 0.236 -------- 60 elap. sec elap sec . If the CPU secs/Elap sec ratio is greater than one, more than one CPU processor capacity would be required to drive the workload. . Total CPU Utilization: . CPU secs/Elap Sec ----------------- * 100 % = CPU Util % # of processors . # of processors: 4 ( This will be equal to number of 390 processors used for the LPAR) . Example: Therefore, Percentage of CPU utilization on Four CP LPAR to drive 6 tran/user/minute for 4,000 users will be . 0.236 CPU secs/Elap sec ----------------------- * 100 % = 5.9 % 4 processors . Thus, the total CPU requirement for 4000 TN3270 users would require 5.9 % of a four processor IBM 9672-RX6 machine. LSPR can be used to adjust for other processors types. Consult your IBM marketing representative or systems engineer to get the correct relationship in processing power between the different IBM processors. . FTP Capacity Planning: ===================== The methodology for FTP capacity planning is very similar to Telnet. The key difference is that one needs to determine the average cost for transferring a Kbytes of data on a given setup, i.e., machine type, channel attached device, type of workstation, type of transfer, etc.. One can derive the CPU cost using the selected setup by repeating FTP transfers of large files. CPU cost per Kbyte must include TCPIP, VTAM and FTP address space usage. . Total (TCPIP+VTAM+FTP) CPU Requirements for FTP transfer: . Max KB CPU secs CPU secs --------- * --------- = ---------- Elap secs KB Elap secs . For example, if we are interested in driving aggregate effective FTP throughput of 10000 KBytes/Second for transferring data from workstations to MVS using 2216 as the Channel attached device and FDDI as the LAN media on ES9672-RX5 3 CP LPAR: From our FTP measurements of binary PUT, 20 Mbytes file transfer, we have determined that CPU cost per Kbyte is 0.0000347 CPU seconds. . 10000 KB .0000347 .347 CPU secs --------- * ------------ = ---------- Elap secs KB Elap secs . If the CPU secs/Elap sec ratio is 1 or greater, one would need more than one processor capacity to drive the desired throughput. . MVS TCP/IP CPU Utilization: . CPU secs/Elap Sec ----------------- * 100 % = CPU Util % # of processors . # of processors: 4 ( This will be equal to number of 390 processors used for the LPAR) . Example: For our example we are using ES9672-RX5 4 processor LPAR. Therefore, Total CPU utilization will be . 0.347 CPU secs/Elap sec ----------------------- * 100 % = 8.675 % 4 processor . Thus, Total CPU (TCPIP+VTAM+FTP) requirements for driving 10000 Kbytes/second throughput on ES9672-RX5 (4 CP LPAR) will be 8.675 %. If you are using different type of mainframe, but keeping the other setup same, you can use the LSPR information to adjust the above CPU utilization. Consult your IBM marketing representative or systems engineer to get the correct relationship in processing power between the different IBM processors. The above methodology can be used for deriving the capacity planning for different types of workload
Local fix
Problem summary
Problem conclusion
Temporary fix
Comments
APAR Information
APAR number
II11712
Reported component name
PA LIB INFO ITE
Reported component ID
INFOPALIB
Reported release
001
Status
CLOSED CAN
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
1999-02-23
Closed date
1999-03-08
Last modified date
2009-02-18
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Applicable component levels
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Document Information
Modified date:
18 February 2009