https://community.hpe.com/t5/operating-system-openvms/io-prefer-cpus-not-behaving-as-expected/m-p/3363681#M3494 Hi<BR /><BR />Even though I've set IO_PREFER_CPUS to FFFC on this 16-CPU GS160, it still appears as if only CPU-0 and CPU-5 are handling all the interrupts.<BR /><BR />CPU-0 is probably handling network I/Os, and CPU-5 the disk I/Os. But what about the rest? Why aren't they handling any interrupts?<BR /><BR />Hope you can help.<BR /> Tue, 24 Aug 2004 01:52:23 GMT Christof Schoeman 2004-08-24T01:52:23Z https://community.hpe.com/t5/operating-system-openvms/io-prefer-cpus-not-behaving-as-expected/m-p/3363681#M3494 Hi<BR /><BR />Even though I've set IO_PREFER_CPUS to FFFC on this 16-CPU GS160, it still appears as if only CPU-0 and CPU-5 are handling all the interrupts.<BR /><BR />CPU-0 is probably handling network I/Os, and CPU-5 the disk I/Os. But what about the rest? Why aren't they handling any interrupts?<BR /><BR />Hope you can help.<BR /> Tue, 24 Aug 2004 01:52:23 GMT https://community.hpe.com/t5/operating-system-openvms/io-prefer-cpus-not-behaving-as-expected/m-p/3363681#M3494 Christof Schoeman 2004-08-24T01:52:23Z https://community.hpe.com/t5/operating-system-openvms/io-prefer-cpus-not-behaving-as-expected/m-p/3363682#M3495 Christof,<BR /><BR /> IO_PREFER_CPUS controls the set of CPUs *available* for Fast Path I/O processing, it does not, in itself enable fast path.<BR /><BR /> SYSGEN parameters FAST_PATH and FAST_PATH_PORTS also need to be set correctly for your version and hardware (in recent versions they are enabled by default).<BR /><BR /> Finally, the selected devices themselves need to be enabled with <BR /><BR />SET DEVICE/PREFERRED_CPUS=cpu,...<BR /><BR /> See the HP I/O User's Reference Manual for more detail in configuring Fast Path. Tue, 24 Aug 2004 20:59:53 GMT https://community.hpe.com/t5/operating-system-openvms/io-prefer-cpus-not-behaving-as-expected/m-p/3363682#M3495 John Gillings 2004-08-24T20:59:53Z