On Wed, Nov 02, 2022 at 04:00:05PM +0000, Colton Lewis wrote:
> Create a -r argument to specify a random seed. If no argument is
> provided, the seed defaults to 1. The random seed is set with
> perf_test_set_random_seed() and must be set before guest_code runs to
> apply.
>
> Signed-off-by: Colton Lewis <coltonlewis@xxxxxxxxxx>
> ---
> tools/testing/selftests/kvm/dirty_log_perf_test.c | 12 ++++++++++--
> tools/testing/selftests/kvm/include/perf_test_util.h | 2 ++
> tools/testing/selftests/kvm/lib/perf_test_util.c | 6 ++++++
> 3 files changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c
> index f99e39a672d3..c97a5e455699 100644
> --- a/tools/testing/selftests/kvm/dirty_log_perf_test.c
> +++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c
> @@ -132,6 +132,7 @@ struct test_params {
> bool partition_vcpu_memory_access;
> enum vm_mem_backing_src_type backing_src;
> int slots;
> + uint32_t random_seed;
> };
>
> static void toggle_dirty_logging(struct kvm_vm *vm, int slots, bool enable)
> @@ -225,6 +226,9 @@ static void run_test(enum vm_guest_mode mode, void *arg)
> p->slots, p->backing_src,
> p->partition_vcpu_memory_access);
>
> + /* If no argument provided, random seed will be 1. */
> + pr_info("Random seed: %u\n", p->random_seed);
> + perf_test_set_random_seed(vm, p->random_seed ? p->random_seed : 1);
If the user passes `-r 0` or does not pass `-r` at all, this will print
"Random seed: 0" and then proceed to use 1 as the random seed, which
seems unnecessarily misleading.
If you want the default random seed to be 1, you can initialize
p.random_seed to 1 before argument parsing (where all the other
test_params are default initialized), then the value you print here will
be accurate and you don't need the comment or ternary operator.
> perf_test_set_wr_fract(vm, p->wr_fract);
>
> guest_num_pages = (nr_vcpus * guest_percpu_mem_size) >> vm->page_shift;
> @@ -352,7 +356,7 @@ static void help(char *name)
> {
> puts("");
> printf("usage: %s [-h] [-i iterations] [-p offset] [-g] "
> - "[-m mode] [-n] [-b vcpu bytes] [-v vcpus] [-o] [-s mem type]"
> + "[-m mode] [-n] [-b vcpu bytes] [-v vcpus] [-o] [-r random seed ] [-s mem type]"
> "[-x memslots]\n", name);
> puts("");
> printf(" -i: specify iteration counts (default: %"PRIu64")\n",
> @@ -380,6 +384,7 @@ static void help(char *name)
> printf(" -v: specify the number of vCPUs to run.\n");
> printf(" -o: Overlap guest memory accesses instead of partitioning\n"
> " them into a separate region of memory for each vCPU.\n");
> + printf(" -r: specify the starting random seed.\n");
> backing_src_help("-s");
> printf(" -x: Split the memory region into this number of memslots.\n"
> " (default: 1)\n");
> @@ -406,7 +411,7 @@ int main(int argc, char *argv[])
>
> guest_modes_append_default();
>
> - while ((opt = getopt(argc, argv, "eghi:p:m:nb:f:v:os:x:")) != -1) {
> + while ((opt = getopt(argc, argv, "eghi:p:m:nb:f:v:or:s:x:")) != -1) {
> switch (opt) {
> case 'e':
> /* 'e' is for evil. */
> @@ -442,6 +447,9 @@ int main(int argc, char *argv[])
> case 'o':
> p.partition_vcpu_memory_access = false;
> break;
> + case 'r':
> + p.random_seed = atoi(optarg);
> + break;
> case 's':
> p.backing_src = parse_backing_src_type(optarg);
> break;
> diff --git a/tools/testing/selftests/kvm/include/perf_test_util.h b/tools/testing/selftests/kvm/include/perf_test_util.h
> index eaa88df0555a..f1050fd42d10 100644
> --- a/tools/testing/selftests/kvm/include/perf_test_util.h
> +++ b/tools/testing/selftests/kvm/include/perf_test_util.h
> @@ -35,6 +35,7 @@ struct perf_test_args {
> uint64_t gpa;
> uint64_t size;
> uint64_t guest_page_size;
> + uint32_t random_seed;
> int wr_fract;
>
> /* Run vCPUs in L2 instead of L1, if the architecture supports it. */
> @@ -52,6 +53,7 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int nr_vcpus,
> void perf_test_destroy_vm(struct kvm_vm *vm);
>
> void perf_test_set_wr_fract(struct kvm_vm *vm, int wr_fract);
> +void perf_test_set_random_seed(struct kvm_vm *vm, uint32_t random_seed);
>
> void perf_test_start_vcpu_threads(int vcpus, void (*vcpu_fn)(struct perf_test_vcpu_args *));
> void perf_test_join_vcpu_threads(int vcpus);
> diff --git a/tools/testing/selftests/kvm/lib/perf_test_util.c b/tools/testing/selftests/kvm/lib/perf_test_util.c
> index 9618b37c66f7..0bb0659b9a0d 100644
> --- a/tools/testing/selftests/kvm/lib/perf_test_util.c
> +++ b/tools/testing/selftests/kvm/lib/perf_test_util.c
> @@ -229,6 +229,12 @@ void perf_test_set_wr_fract(struct kvm_vm *vm, int wr_fract)
> sync_global_to_guest(vm, perf_test_args);
> }
>
> +void perf_test_set_random_seed(struct kvm_vm *vm, uint32_t random_seed)
> +{
> + perf_test_args.random_seed = random_seed;
> + sync_global_to_guest(vm, perf_test_args.random_seed);
> +}
> +
> uint64_t __weak perf_test_nested_pages(int nr_vcpus)
> {
> return 0;
> --
> 2.38.1.273.g43a17bfeac-goog
>
