FYI, with the old cpus_allowed_policy=shared mode, the fio threads are indeed moving around quite a lot on linux.
Printing the thread or process ID (LWP from ps), current CPU (PSR from ps), and the thread affinity mask (from taskset --pid) for each thread while running with the old policy: 11429 currently on 9: pid 11429's current affinity mask: fff 11430 currently on 8: pid 11430's current affinity mask: fff 11432 currently on 5: pid 11432's current affinity mask: ff 11433 currently on 1: pid 11433's current affinity mask: ff 11434 currently on 2: pid 11434's current affinity mask: ff 11435 currently on 6: pid 11435's current affinity mask: ff 11436 currently on 4: pid 11436's current affinity mask: ff 11437 currently on 3: pid 11437's current affinity mask: ff 11438 currently on 7: pid 11438's current affinity mask: ff 11439 currently on 0: pid 11439's current affinity mask: ff 11429 currently on 9: pid 11429's current affinity mask: fff 11430 currently on 8: pid 11430's current affinity mask: fff 11432 currently on 3: pid 11432's current affinity mask: ff 11433 currently on 6: pid 11433's current affinity mask: ff 11434 currently on 1: pid 11434's current affinity mask: ff 11435 currently on 7: pid 11435's current affinity mask: ff 11436 currently on 4: pid 11436's current affinity mask: ff 11437 currently on 2: pid 11437's current affinity mask: ff 11438 currently on 0: pid 11438's current affinity mask: ff 11439 currently on 5: pid 11439's current affinity mask: ff 11429 currently on 9: pid 11429's current affinity mask: fff 11430 currently on 8: pid 11430's current affinity mask: fff 11432 currently on 2: pid 11432's current affinity mask: ff 11433 currently on 4: pid 11433's current affinity mask: ff 11434 currently on 7: pid 11434's current affinity mask: ff 11435 currently on 0: pid 11435's current affinity mask: ff 11436 currently on 1: pid 11436's current affinity mask: ff 11437 currently on 5: pid 11437's current affinity mask: ff 11438 currently on 3: pid 11438's current affinity mask: ff 11439 currently on 6: pid 11439's current affinity mask: ff With the new cpus_allowed_policy=split they stay put: 11649 currently on 2: pid 11649's current affinity mask: fff 11650 currently on 9: pid 11650's current affinity mask: fff 11653 currently on 0: pid 11653's current affinity mask: 1 11654 currently on 1: pid 11654's current affinity mask: 2 11655 currently on 2: pid 11655's current affinity mask: 4 11656 currently on 3: pid 11656's current affinity mask: 8 11657 currently on 4: pid 11657's current affinity mask: 10 11658 currently on 5: pid 11658's current affinity mask: 20 11659 currently on 6: pid 11659's current affinity mask: 40 11660 currently on 7: pid 11660's current affinity mask: 80 11649 currently on 10: pid 11649's current affinity mask: fff 11650 currently on 9: pid 11650's current affinity mask: fff 11653 currently on 0: pid 11653's current affinity mask: 1 11654 currently on 1: pid 11654's current affinity mask: 2 11655 currently on 2: pid 11655's current affinity mask: 4 11656 currently on 3: pid 11656's current affinity mask: 8 11657 currently on 4: pid 11657's current affinity mask: 10 11658 currently on 5: pid 11658's current affinity mask: 20 11659 currently on 6: pid 11659's current affinity mask: 40 11660 currently on 7: pid 11660's current affinity mask: 80 On one particular test, this repeatedly boosts 810K IOPS to 820K IOPS. --- Rob Elliott HP Server Storage -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
