| Message ID | 20220901195237.2152238-2-coltonlewis@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Randomize memory access of dirty_log_perf_test | expand |
On Thu, Sep 01, 2022 at 07:52:35PM +0000, Colton Lewis wrote: > Implement random number generation for guest code to randomize parts > of the test, making it less predictable and a more accurate reflection > of reality. > > Create a -r argument to specify a random seed. If no argument is > provided, the seed defaults to the current Unix timestamp. > > The random number generator chosen is the Park-Miller Linear > Congruential Generator, a fancy name for a basic and well-understood > random number generator entirely sufficient for this purpose. Each > vCPU calculates its own seed by adding its index to the seed provided. > > Signed-off-by: Colton Lewis <coltonlewis@google.com> > --- > .../selftests/kvm/dirty_log_perf_test.c | 12 ++++++++++-- > .../selftests/kvm/include/perf_test_util.h | 2 ++ > .../testing/selftests/kvm/lib/perf_test_util.c | 18 +++++++++++++++++- > 3 files changed, 29 insertions(+), 3 deletions(-) > > diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c > index d60a34cdfaee..2f91acd94130 100644 > --- a/tools/testing/selftests/kvm/dirty_log_perf_test.c > +++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c > @@ -126,6 +126,7 @@ 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) > @@ -220,6 +221,8 @@ static void run_test(enum vm_guest_mode mode, void *arg) > p->slots, p->backing_src, > p->partition_vcpu_memory_access); > > + pr_info("Random seed: %u\n", p->random_seed); > + perf_test_set_random_seed(vm, p->random_seed); > perf_test_set_wr_fract(vm, p->wr_fract); > > guest_num_pages = (nr_vcpus * guest_percpu_mem_size) >> vm_get_page_shift(vm); > @@ -337,7 +340,7 @@ 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", > @@ -362,6 +365,7 @@ 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"); > @@ -378,6 +382,7 @@ int main(int argc, char *argv[]) > .partition_vcpu_memory_access = true, > .backing_src = DEFAULT_VM_MEM_SRC, > .slots = 1, > + .random_seed = time(NULL), > }; > int opt; > > @@ -388,7 +393,7 @@ int main(int argc, char *argv[]) > > guest_modes_append_default(); > > - while ((opt = getopt(argc, argv, "ghi:p:m:nb:f:v:os:x:")) != -1) { > + while ((opt = getopt(argc, argv, "ghi:p:m:nb:f:v:or:s:x:")) != -1) { > switch (opt) { > case 'g': > dirty_log_manual_caps = 0; > @@ -421,6 +426,9 @@ 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 d822cb670f1c..f18530984b42 100644 > --- a/tools/testing/selftests/kvm/include/perf_test_util.h > +++ b/tools/testing/selftests/kvm/include/perf_test_util.h > @@ -34,6 +34,7 @@ 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. */ > @@ -51,6 +52,7 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int 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 f989ff91f022..1292ed7d1193 100644 > --- a/tools/testing/selftests/kvm/lib/perf_test_util.c > +++ b/tools/testing/selftests/kvm/lib/perf_test_util.c > @@ -36,6 +36,13 @@ static void (*vcpu_thread_fn)(struct perf_test_vcpu_args *); > /* Set to true once all vCPU threads are up and running. */ > static bool all_vcpu_threads_running; > > + > +/* Park-Miller LCG using standard constants */ > +static uint32_t perf_test_random(uint32_t seed) > +{ > + return (uint64_t)seed * 48271 % ((uint32_t)(1 << 31) - 1); > +} Nit: I would prefer moving this to include/kvm_test_util.h, maybe something like: get_next_random(seed). There could be other users of this. > + > /* > * Continuously write to the first 8 bytes of each page in the > * specified region. > @@ -47,6 +54,7 @@ void perf_test_guest_code(uint32_t vcpu_id) > uint64_t gva; > uint64_t pages; > int i; > + uint32_t rand = pta->random_seed + vcpu_id; > > /* Make sure vCPU args data structure is not corrupt. */ > GUEST_ASSERT(vcpu_args->vcpu_id == vcpu_id); > @@ -56,6 +64,7 @@ void perf_test_guest_code(uint32_t vcpu_id) > > while (true) { > for (i = 0; i < pages; i++) { > + rand = perf_test_random(rand); > uint64_t addr = gva + (i * pta->guest_page_size); > > if (i % pta->wr_fract == 0) > @@ -115,8 +124,9 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int vcpus, > > pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode)); > > - /* By default vCPUs will write to memory. */ > + /* Set perf_test_args defaults. */ > pta->wr_fract = 1; > + pta->random_seed = time(NULL); > > /* > * Snapshot the non-huge page size. This is used by the guest code to > @@ -224,6 +234,12 @@ 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); > +} > + > uint64_t __weak perf_test_nested_pages(int nr_vcpus) > { > return 0; > -- > 2.37.2.789.g6183377224-goog >
On Thu, Sep 01, 2022 at 07:52:35PM +0000, Colton Lewis wrote: > Implement random number generation for guest code to randomize parts > of the test, making it less predictable and a more accurate reflection > of reality. > > Create a -r argument to specify a random seed. If no argument is > provided, the seed defaults to the current Unix timestamp. > > The random number generator chosen is the Park-Miller Linear > Congruential Generator, a fancy name for a basic and well-understood > random number generator entirely sufficient for this purpose. Each > vCPU calculates its own seed by adding its index to the seed provided. > Reviewed-by: Ricardo Koller <ricarkol@google.com> > Signed-off-by: Colton Lewis <coltonlewis@google.com> > --- > .../selftests/kvm/dirty_log_perf_test.c | 12 ++++++++++-- > .../selftests/kvm/include/perf_test_util.h | 2 ++ > .../testing/selftests/kvm/lib/perf_test_util.c | 18 +++++++++++++++++- > 3 files changed, 29 insertions(+), 3 deletions(-) > > diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c > index d60a34cdfaee..2f91acd94130 100644 > --- a/tools/testing/selftests/kvm/dirty_log_perf_test.c > +++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c > @@ -126,6 +126,7 @@ 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) > @@ -220,6 +221,8 @@ static void run_test(enum vm_guest_mode mode, void *arg) > p->slots, p->backing_src, > p->partition_vcpu_memory_access); > > + pr_info("Random seed: %u\n", p->random_seed); > + perf_test_set_random_seed(vm, p->random_seed); > perf_test_set_wr_fract(vm, p->wr_fract); > > guest_num_pages = (nr_vcpus * guest_percpu_mem_size) >> vm_get_page_shift(vm); > @@ -337,7 +340,7 @@ 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", > @@ -362,6 +365,7 @@ 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"); > @@ -378,6 +382,7 @@ int main(int argc, char *argv[]) > .partition_vcpu_memory_access = true, > .backing_src = DEFAULT_VM_MEM_SRC, > .slots = 1, > + .random_seed = time(NULL), > }; > int opt; > > @@ -388,7 +393,7 @@ int main(int argc, char *argv[]) > > guest_modes_append_default(); > > - while ((opt = getopt(argc, argv, "ghi:p:m:nb:f:v:os:x:")) != -1) { > + while ((opt = getopt(argc, argv, "ghi:p:m:nb:f:v:or:s:x:")) != -1) { > switch (opt) { > case 'g': > dirty_log_manual_caps = 0; > @@ -421,6 +426,9 @@ 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 d822cb670f1c..f18530984b42 100644 > --- a/tools/testing/selftests/kvm/include/perf_test_util.h > +++ b/tools/testing/selftests/kvm/include/perf_test_util.h > @@ -34,6 +34,7 @@ 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. */ > @@ -51,6 +52,7 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int 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 f989ff91f022..1292ed7d1193 100644 > --- a/tools/testing/selftests/kvm/lib/perf_test_util.c > +++ b/tools/testing/selftests/kvm/lib/perf_test_util.c > @@ -36,6 +36,13 @@ static void (*vcpu_thread_fn)(struct perf_test_vcpu_args *); > /* Set to true once all vCPU threads are up and running. */ > static bool all_vcpu_threads_running; > > + > +/* Park-Miller LCG using standard constants */ > +static uint32_t perf_test_random(uint32_t seed) > +{ > + return (uint64_t)seed * 48271 % ((uint32_t)(1 << 31) - 1); > +} > + > /* > * Continuously write to the first 8 bytes of each page in the > * specified region. > @@ -47,6 +54,7 @@ void perf_test_guest_code(uint32_t vcpu_id) > uint64_t gva; > uint64_t pages; > int i; > + uint32_t rand = pta->random_seed + vcpu_id; > > /* Make sure vCPU args data structure is not corrupt. */ > GUEST_ASSERT(vcpu_args->vcpu_id == vcpu_id); > @@ -56,6 +64,7 @@ void perf_test_guest_code(uint32_t vcpu_id) > > while (true) { > for (i = 0; i < pages; i++) { > + rand = perf_test_random(rand); > uint64_t addr = gva + (i * pta->guest_page_size); > > if (i % pta->wr_fract == 0) > @@ -115,8 +124,9 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int vcpus, > > pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode)); > > - /* By default vCPUs will write to memory. */ > + /* Set perf_test_args defaults. */ > pta->wr_fract = 1; > + pta->random_seed = time(NULL); > > /* > * Snapshot the non-huge page size. This is used by the guest code to > @@ -224,6 +234,12 @@ 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); > +} > + > uint64_t __weak perf_test_nested_pages(int nr_vcpus) > { > return 0; > -- > 2.37.2.789.g6183377224-goog >
diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c index d60a34cdfaee..2f91acd94130 100644 --- a/tools/testing/selftests/kvm/dirty_log_perf_test.c +++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c @@ -126,6 +126,7 @@ 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) @@ -220,6 +221,8 @@ static void run_test(enum vm_guest_mode mode, void *arg) p->slots, p->backing_src, p->partition_vcpu_memory_access); + pr_info("Random seed: %u\n", p->random_seed); + perf_test_set_random_seed(vm, p->random_seed); perf_test_set_wr_fract(vm, p->wr_fract); guest_num_pages = (nr_vcpus * guest_percpu_mem_size) >> vm_get_page_shift(vm); @@ -337,7 +340,7 @@ 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", @@ -362,6 +365,7 @@ 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"); @@ -378,6 +382,7 @@ int main(int argc, char *argv[]) .partition_vcpu_memory_access = true, .backing_src = DEFAULT_VM_MEM_SRC, .slots = 1, + .random_seed = time(NULL), }; int opt; @@ -388,7 +393,7 @@ int main(int argc, char *argv[]) guest_modes_append_default(); - while ((opt = getopt(argc, argv, "ghi:p:m:nb:f:v:os:x:")) != -1) { + while ((opt = getopt(argc, argv, "ghi:p:m:nb:f:v:or:s:x:")) != -1) { switch (opt) { case 'g': dirty_log_manual_caps = 0; @@ -421,6 +426,9 @@ 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 d822cb670f1c..f18530984b42 100644 --- a/tools/testing/selftests/kvm/include/perf_test_util.h +++ b/tools/testing/selftests/kvm/include/perf_test_util.h @@ -34,6 +34,7 @@ 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. */ @@ -51,6 +52,7 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int 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 f989ff91f022..1292ed7d1193 100644 --- a/tools/testing/selftests/kvm/lib/perf_test_util.c +++ b/tools/testing/selftests/kvm/lib/perf_test_util.c @@ -36,6 +36,13 @@ static void (*vcpu_thread_fn)(struct perf_test_vcpu_args *); /* Set to true once all vCPU threads are up and running. */ static bool all_vcpu_threads_running; + +/* Park-Miller LCG using standard constants */ +static uint32_t perf_test_random(uint32_t seed) +{ + return (uint64_t)seed * 48271 % ((uint32_t)(1 << 31) - 1); +} + /* * Continuously write to the first 8 bytes of each page in the * specified region. @@ -47,6 +54,7 @@ void perf_test_guest_code(uint32_t vcpu_id) uint64_t gva; uint64_t pages; int i; + uint32_t rand = pta->random_seed + vcpu_id; /* Make sure vCPU args data structure is not corrupt. */ GUEST_ASSERT(vcpu_args->vcpu_id == vcpu_id); @@ -56,6 +64,7 @@ void perf_test_guest_code(uint32_t vcpu_id) while (true) { for (i = 0; i < pages; i++) { + rand = perf_test_random(rand); uint64_t addr = gva + (i * pta->guest_page_size); if (i % pta->wr_fract == 0) @@ -115,8 +124,9 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int vcpus, pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode)); - /* By default vCPUs will write to memory. */ + /* Set perf_test_args defaults. */ pta->wr_fract = 1; + pta->random_seed = time(NULL); /* * Snapshot the non-huge page size. This is used by the guest code to @@ -224,6 +234,12 @@ 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); +} + uint64_t __weak perf_test_nested_pages(int nr_vcpus) { return 0;
Implement random number generation for guest code to randomize parts of the test, making it less predictable and a more accurate reflection of reality. Create a -r argument to specify a random seed. If no argument is provided, the seed defaults to the current Unix timestamp. The random number generator chosen is the Park-Miller Linear Congruential Generator, a fancy name for a basic and well-understood random number generator entirely sufficient for this purpose. Each vCPU calculates its own seed by adding its index to the seed provided. Signed-off-by: Colton Lewis <coltonlewis@google.com> --- .../selftests/kvm/dirty_log_perf_test.c | 12 ++++++++++-- .../selftests/kvm/include/perf_test_util.h | 2 ++ .../testing/selftests/kvm/lib/perf_test_util.c | 18 +++++++++++++++++- 3 files changed, 29 insertions(+), 3 deletions(-)