Checking XCF/XES connectivity and performance
In both ring and star complexes, XCF and XES connectivity are critical to global resource serialization function. If either are not well tuned, the performance of the allocation of global resource requests will suffer. If your installation is running a global resource serialization ring complex, see System/390 Parallel Sysplex Performance to ensure optimal tuning of the sysplex.
In a global resource serialization star complex, you should apply appropriate resource to the coupling facility where you have allocated the ISGLOCK structure. Make sure that the structure is large enough to minimize false contention and that the coupling facility containing the ISGLOCK structure is fast enough to satisfy lock requests from the z/OS images. If you do not, you could see the following problems with your global resource serialization complex:
Symptom | Likely causes |
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Excessive processor utilization in the global resource serialization address space |
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Long ENQ response times |
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ENQ requests suspended |
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The Coupling Facility Structure Sizer Tool (CFSIZER) is a web based application that will return the structure sizes based on the latest CFLEVEL for the IBM® products that exploit the Coupling Facility. See z/OS Internet Library.