Poor Performance Transmitting Report Data after Upgrading to z/OS 1.6 or 1.7

Document ID : KB000055717
Last Modified Date : 14/02/2018
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If you notice that report transmission is slower after upgrading to z/OS 1.6 or 1.7, it may be due to an IBM problem. Reports that took seconds to transmit, can now take minutes.

The IBM problem is:

PK12893: POOR TCP PERFORMANCE WHEN USING TCP SEGMENTATION OFFLOAD AND APPLICATIONS WITH SMALL DATA WRITES.
http://www-1.ibm.com/support/docview.wss?rs=884&uid=isg1PK12893

You may be able to use a TCPIP sniffer to determine if you have this problem. The apar text has other instructions to verify the problem scenario as well as a workaround and information about apars for z/OS 1.6 and 1.7.