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Tuning Enterprise Extender-specific buffer pools z/OS Communications Server: SNA Network Implementation Guide SC27-3672-01 |
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Enterprise Extender performance degradation can be caused by poorly tuned buffers. Monitor and tune the T1BUF and T2BUF buffer pools to minimize the number of expansions. Minimizing buffer pool expansions decreases internal buffer overhead processing, which should increase throughput while reducing CPU consumption. Also, the T1BUF and T2BUF pools are used instead of the TIBUF buffer pool. Increasing the buffer pool values for the T1BUF, T2BUF, or both might decrease the buffers necessary for the TIBUF pool. You should also monitor and tune the TIBUF pool. Use IBM® Health Checker for z/OS® to check whether the T1BUF and T2BUF start option definitions for the initial number of buffers in the pool are greater than the default value when Enterprise Extender (EE) is not being used. You can also use Health Checker to check whether the initial number of buffers specified for these two buffer pools is equal to the default value when EE is being used with QDIO or HiperSockets™. For more details about IBM Health Checker for z/OS, see z/OS Communications Server: IP Diagnosis Guide. The following is a buffer pool display example.
In this example, the T2BUF (T200) buffer pool expanded 406,920 times. At any given time, the maximum number of T2BUF buffers used at one time was 1576. This example indicates that the T2BUF buffer pool is thrashing, constantly expanding and contracting to meet the needs of its environment. A large number of expansions indicates that buffer pool tuning is warranted. In this case, coding a base allocation of 1576 buffers or more will eliminate the buffer pool thrashing for the T2BUF buffer pool. Use a similar approach when tuning your T1BUF buffers. In this example, the T1BUF pool does not need tuning (three expansions is considered minor). |
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