Re: [PATCH 0/6] KVM: selftests: Perf test cleanups and memslot modification test

[Paolo Bonzini]

On 12/01/21 22:42, Ben Gardon wrote:
> This series contains a few cleanups that didn't make it into previous
> series, including some cosmetic changes and small bug fixes. The series
> also lays the groundwork for a memslot modification test which stresses
> the memslot update and page fault code paths in an attempt to expose races.
>
> Tested: dirty_log_perf_test, memslot_modification_stress_test, and
> 	demand_paging_test were run, with all the patches in this series
> 	applied, on an Intel Skylake machine.
>
> 	echo Y > /sys/module/kvm/parameters/tdp_mmu; \
> 	./memslot_modification_stress_test -i 1000 -v 64 -b 1G; \
> 	./memslot_modification_stress_test -i 1000 -v 64 -b 64M -o; \
> 	./dirty_log_perf_test -v 64 -b 1G; \
> 	./dirty_log_perf_test -v 64 -b 64M -o; \
> 	./demand_paging_test -v 64 -b 1G; \
> 	./demand_paging_test -v 64 -b 64M -o; \
> 	echo N > /sys/module/kvm/parameters/tdp_mmu; \
> 	./memslot_modification_stress_test -i 1000 -v 64 -b 1G; \
> 	./memslot_modification_stress_test -i 1000 -v 64 -b 64M -o; \
> 	./dirty_log_perf_test -v 64 -b 1G; \
> 	./dirty_log_perf_test -v 64 -b 64M -o; \
> 	./demand_paging_test -v 64 -b 1G; \
> 	./demand_paging_test -v 64 -b 64M -o
>
> 	The tests behaved as expected, and fixed the problem of the
> 	population stage being skipped in dirty_log_perf_test. This can be
> 	seen in the output, with the population stage taking about the time
> 	dirty pass 1 took and dirty pass 1 falling closer to the times for
> 	the other passes.
>
> Note that when running these tests, the -o option causes the test to take
> much longer as the work each vCPU must do increases proportional to the
> number of vCPUs.
>
> You can view this series in Gerrit at:
> https://linux-review.googlesource.com/c/linux/kernel/git/torvalds/linux/+/7216
>
> Ben Gardon (6):
>    KVM: selftests: Rename timespec_diff_now to timespec_elapsed
>    KVM: selftests: Avoid flooding debug log while populating memory
>    KVM: selftests: Convert iterations to int in dirty_log_perf_test
>    KVM: selftests: Fix population stage in dirty_log_perf_test
>    KVM: selftests: Add option to overlap vCPU memory access
>    KVM: selftests: Add memslot modification stress test
>
>   tools/testing/selftests/kvm/.gitignore        |   1 +
>   tools/testing/selftests/kvm/Makefile          |   1 +
>   .../selftests/kvm/demand_paging_test.c        |  40 +++-
>   .../selftests/kvm/dirty_log_perf_test.c       |  72 +++---
>   .../selftests/kvm/include/perf_test_util.h    |   4 +-
>   .../testing/selftests/kvm/include/test_util.h |   2 +-
>   .../selftests/kvm/lib/perf_test_util.c        |  25 ++-
>   tools/testing/selftests/kvm/lib/test_util.c   |   2 +-
>   .../kvm/memslot_modification_stress_test.c    | 211 ++++++++++++++++++
>   9 files changed, 307 insertions(+), 51 deletions(-)
>   create mode 100644 tools/testing/selftests/kvm/memslot_modification_stress_test.c

Queued, thanks.

Paolo