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[34.125.103.223]) by smtp.gmail.com with ESMTPSA id bb16-20020a17090b009000b00212d4cbcbfdsm188724pjb.22.2022.11.03.09.27.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Nov 2022 09:27:48 -0700 (PDT) Date: Thu, 3 Nov 2022 09:27:44 -0700 From: David Matlack To: Colton Lewis Cc: kvm@vger.kernel.org, pbonzini@redhat.com, maz@kernel.org, seanjc@google.com, oupton@google.com, ricarkol@google.com Subject: Re: [PATCH v9 2/4] KVM: selftests: create -r argument to specify random seed Message-ID: References: <20221102160007.1279193-1-coltonlewis@google.com> <20221102160007.1279193-3-coltonlewis@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221102160007.1279193-3-coltonlewis@google.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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 > --- > 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 >