Add support to dirty-ring on dirty_log_perf_test, so we can measure performance differences when we change / improve the mechanism.
One big change in this set is that dirty-ring needs to be enabled after the VM was created, but before any cpu is created, so for that, I made a few changes on memstress so it can actually take dirty-ring size as a parameter for VM creation. (Patches #1 & #2) Also added some checks in dirty-ring enable, so an error message on ring size is more informative. Please provide feedback :) Thanks! Leo Changes since v1: - Converted memstress to take a memstress_params struct instead of a lot of parameters, so it could be more easily extended in the future (Sean) - Moved dirty-ring cap detection to a helper, so it could be used instead of open-coded options (Sean) - Improved the error messages in case the dirty-ring fails to setup, with a more specific message on what went wrong (Sean) Link: https://lore.kernel.org/all/[email protected]/ Changes since RFCv4: - Series title - Rebase on v7.3-rc5 Link: https://lore.kernel.org/all/[email protected]/ - Using acquire/release barriers to make sure there is no reorder between incrementing iteration and summing the time spent on cleaning. - Improved ring-size checks, although not perfect due to reserved entries affecting minimum size. - Do not allocate bitmaps for dirty-ring tests, as they are unused. - Improve help text - Make sure ret==0 before going back to vcpu_run in dirty-ring case Link: https://lore.kernel.org/all/[email protected]/ Changes since RFCv2: - Added mutex to make sure only a single vcpu is collecting/cleaning at a time. This gets us the ability to test return values, and not account for kvm.slot_lock waiting time. - Stuff reported by Sashiko - Return value always positive, so assert was pointless - Concurrency inflating the time for dirty-ring cleaning Link: https://lore.kernel.org/all/[email protected]/ Changes since RFCv1: - Stuff reported by Sashiko - Fixed elements / byte size wrapping issue - Removed element count due to concurrency - Testing exit_reason instead of ioctl return value - Some nits Link: https://lore.kernel.org/all/[email protected]/ Leonardo Bras (5): KVM: selftests: memstress: Add struct memstress_params, make memstress_create_vm() use it KVM: selftests: memstress: Add option to enable dirty-ring on VM creation KVM: selftests: Introduce kvm_get_dirty_ring_cap() KVM: selftests: Check dirty-ring size before enabling KVM: selftests: dirty_log_perf_test: Add dirty-ring support .../testing/selftests/kvm/include/kvm_util.h | 11 ++ .../testing/selftests/kvm/include/memstress.h | 15 +- .../selftests/kvm/access_tracking_perf_test.c | 12 +- .../selftests/kvm/demand_paging_test.c | 12 +- .../selftests/kvm/dirty_log_perf_test.c | 140 ++++++++++++++++-- tools/testing/selftests/kvm/dirty_log_test.c | 3 +- tools/testing/selftests/kvm/lib/kvm_util.c | 20 ++- tools/testing/selftests/kvm/lib/memstress.c | 68 +++++---- .../kvm/memslot_modification_stress_test.c | 14 +- .../kvm/x86/dirty_log_page_splitting_test.c | 12 +- 10 files changed, 247 insertions(+), 60 deletions(-) base-commit: a90ee4305c4a5df72c11b31dacfdc76e00fcf78a -- 2.55.0
