kernel.git/tools/testing/selftests/kvm/lib/perf_test_util.c, branch linux-5.17.y

KVM: selftests: Wait for all vCPU to be created before entering guest mode

2021-11-16T12:43:28Z

Thread creation requires taking the mmap_sem in write mode, which causes vCPU threads running in guest mode to block while they are populating memory. Fix this by waiting for all vCPU threads to be created and start running before entering guest mode on any one vCPU thread. This substantially improves the "Populate memory time" when using 1GiB pages since it allows all vCPUs to zero pages in parallel rather than blocking because a writer is waiting (which is waiting for another vCPU that is busy zeroing a 1GiB page). Before: $ ./dirty_log_perf_test -v256 -s anonymous_hugetlb_1gb ... Populate memory time: 52.811184013s After: $ ./dirty_log_perf_test -v256 -s anonymous_hugetlb_1gb ... Populate memory time: 10.204573342s Signed-off-by: David Matlack Message-Id: <20211111001257.1446428-4-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Move vCPU thread creation and joining to common helpers

2021-11-16T12:43:28Z

Move vCPU thread creation and joining to common helper functions. This is in preparation for the next commit which ensures that all vCPU threads are fully created before entering guest mode on any one vCPU. No functional change intended. Signed-off-by: David Matlack Reviewed-by: Ben Gardon Message-Id: <20211111001257.1446428-3-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Sync perf_test_args to guest during VM creation

2021-11-16T12:43:27Z

Copy perf_test_args to the guest during VM creation instead of relying on the caller to do so at their leisure. Ideally, tests wouldn't even be able to modify perf_test_args, i.e. they would have no motivation to do the sync, but enforcing that is arguably a net negative for readability. No functional change intended. [Set wr_fract=1 by default and add helper to override it since the new access_tracking_perf_test needs to set it dynamically.] Signed-off-by: Sean Christopherson Signed-off-by: David Matlack Reviewed-by: Ben Gardon Message-Id: <20211111000310.1435032-13-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Fill per-vCPU struct during "perf_test" VM creation

2021-11-16T12:43:27Z

Fill the per-vCPU args when creating the perf_test VM instead of having the caller do so. This helps ensure that any adjustments to the number of pages (and thus vcpu_memory_bytes) are reflected in the per-VM args. Automatically filling the per-vCPU args will also allow a future patch to do the sync to the guest during creation. Signed-off-by: Sean Christopherson [Updated access_tracking_perf_test as well.] Signed-off-by: David Matlack Reviewed-by: Ben Gardon Message-Id: <20211111000310.1435032-12-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Create VM with adjusted number of guest pages for perf tests

2021-11-16T12:43:27Z

Use the already computed guest_num_pages when creating the so called extra VM pages for a perf test, and add a comment explaining why the pages are allocated as extra pages. Signed-off-by: Sean Christopherson Reviewed-by: Ben Gardon Signed-off-by: David Matlack Message-Id: <20211111000310.1435032-11-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Remove perf_test_args.host_page_size

2021-11-16T12:43:26Z

Remove perf_test_args.host_page_size and instead use getpagesize() so that it's somewhat obvious that, for tests that care about the host page size, they care about the system page size, not the hardware page size, e.g. that the logic is unchanged if hugepages are in play. No functional change intended. Signed-off-by: Sean Christopherson Reviewed-by: Ben Gardon Signed-off-by: David Matlack Message-Id: <20211111000310.1435032-10-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Move per-VM GPA into perf_test_args

2021-11-16T12:43:26Z

Move the per-VM GPA into perf_test_args instead of storing it as a separate global variable. It's not obvious that guest_test_phys_mem holds a GPA, nor that it's connected/coupled with per_vcpu->gpa. No functional change intended. Signed-off-by: Sean Christopherson Reviewed-by: Ben Gardon Signed-off-by: David Matlack Message-Id: <20211111000310.1435032-9-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Capture per-vCPU GPA in perf_test_vcpu_args

2021-11-16T12:43:26Z

Capture the per-vCPU GPA in perf_test_vcpu_args so that tests can get the GPA without having to calculate the GPA on their own. No functional change intended. Signed-off-by: Sean Christopherson Reviewed-by: Ben Gardon Signed-off-by: David Matlack Message-Id: <20211111000310.1435032-7-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Use shorthand local var to access struct perf_tests_args

2021-11-16T12:43:25Z

Use 'pta' as a local pointer to the global perf_tests_args in order to shorten line lengths and make the code borderline readable. No functional change intended. Signed-off-by: Sean Christopherson Reviewed-by: Ben Gardon Signed-off-by: David Matlack Message-Id: <20211111000310.1435032-6-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Require GPA to be aligned when backed by hugepages

2021-11-16T12:43:25Z

Assert that the GPA for a memslot backed by a hugepage is aligned to the hugepage size and fix perf_test_util accordingly. Lack of GPA alignment prevents KVM from backing the guest with hugepages, e.g. x86's write-protection of hugepages when dirty logging is activated is otherwise not exercised. Add a comment explaining that guest_page_size is for non-huge pages to try and avoid confusion about what it actually tracks. Cc: Ben Gardon Cc: Yanan Wang Cc: Andrew Jones Cc: Peter Xu Cc: Aaron Lewis Signed-off-by: Sean Christopherson [Used get_backing_src_pagesz() to determine alignment dynamically.] Signed-off-by: David Matlack Message-Id: <20211111000310.1435032-5-dmatlack@google.com> Signed-off-by: Paolo Bonzini