On Mon, Dec 16, 2019 at 01:38:59PM -0800, Ben Gardon wrote:
Most VMs have multiple vCPUs, the concurrent execution of which has a substantial impact on demand paging performance. Add an option to create multiple vCPUs to each access disjoint regions of memory.
Signed-off-by: Ben Gardon bgardon@google.com
.../selftests/kvm/demand_paging_test.c | 199 ++++++++++++------ 1 file changed, 136 insertions(+), 63 deletions(-)
diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c index 8ede26e088ab6..2b80f614dd537 100644 --- a/tools/testing/selftests/kvm/demand_paging_test.c +++ b/tools/testing/selftests/kvm/demand_paging_test.c @@ -24,8 +24,6 @@ #include "kvm_util.h" #include "processor.h" -#define VCPU_ID 1
/* The memory slot index demand page */ #define TEST_MEM_SLOT_INDEX 1 @@ -34,6 +32,12 @@ #define DEFAULT_GUEST_TEST_MEM_SIZE (1 << 30) /* 1G */ +#ifdef PRINT_PER_VCPU_UPDATES +#define PER_VCPU_DEBUG(...) DEBUG(__VA_ARGS__) +#else +#define PER_VCPU_DEBUG(...) +#endif
/*
- Guest/Host shared variables. Ensure addr_gva2hva() and/or
- sync_global_to/from_guest() are used when accessing from
@@ -76,10 +80,6 @@ static void guest_code(uint64_t gva, uint64_t pages) GUEST_SYNC(1); } -/* Points to the test VM memory region on which we are doing demand paging */ -static void *host_test_mem; -static uint64_t host_num_pages;
struct vcpu_thread_args { uint64_t gva; uint64_t pages; @@ -113,18 +113,32 @@ static void *vcpu_worker(void *data) return NULL; } -static struct kvm_vm *create_vm(enum vm_guest_mode mode, uint32_t vcpuid,
uint64_t extra_mem_pages, void *guest_code)+#define PAGE_SHIFT_4K 12 +#define PTES_PER_PT 512
+static struct kvm_vm *create_vm(enum vm_guest_mode mode, int vcpus,
uint64_t vcpu_wss){ struct kvm_vm *vm;
- uint64_t extra_pg_pages = extra_mem_pages / 512 * 2;
- uint64_t pages = DEFAULT_GUEST_PHY_PAGES;
- vm = _vm_create(mode, DEFAULT_GUEST_PHY_PAGES + extra_pg_pages, O_RDWR);
- /* Account for a few pages per-vCPU for stacks */
- pages += DEFAULT_STACK_PGS * vcpus;
- /*
* Reserve twice the ammount of memory needed to map the test region and* the page table / stacks region, at 4k, for page tables. Do the* calculation with 4K page size: the smallest of all archs. (e.g., 64K* page size guest will need even less memory for page tables).*/- pages += (2 * pages) / PTES_PER_PT;
- pages += ((2 * vcpus * vcpu_wss) >> PAGE_SHIFT_4K) / PTES_PER_PT;
- vm = _vm_create(mode, pages, O_RDWR); kvm_vm_elf_load(vm, program_invocation_name, 0, 0);
#ifdef __x86_64__ vm_create_irqchip(vm); #endif
- vm_vcpu_add_default(vm, vcpuid, guest_code); return vm;
} @@ -232,15 +246,13 @@ static void *uffd_handler_thread_fn(void *arg) static int setup_demand_paging(struct kvm_vm *vm, pthread_t *uffd_handler_thread,
useconds_t uffd_delay)
useconds_t uffd_delay,struct uffd_handler_args *uffd_args,void *hva, uint64_t len){ int uffd; struct uffdio_api uffdio_api; struct uffdio_register uffdio_register;
- struct uffd_handler_args uffd_args;
- guest_data_prototype = malloc(host_page_size);
- memset(guest_data_prototype, 0xAB, host_page_size);
uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK); if (uffd == -1) { @@ -255,8 +267,8 @@ static int setup_demand_paging(struct kvm_vm *vm, return -1; }
- uffdio_register.range.start = (uint64_t)host_test_mem;
- uffdio_register.range.len = host_num_pages * host_page_size;
- uffdio_register.range.start = (uint64_t)hva;
- uffdio_register.range.len = len; uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING; if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) == -1) { DEBUG("ioctl uffdio_register failed\n");
@@ -269,42 +281,37 @@ static int setup_demand_paging(struct kvm_vm *vm, return -1; }
- uffd_args.uffd = uffd;
- uffd_args.delay = uffd_delay;
- uffd_args->uffd = uffd;
- uffd_args->delay = uffd_delay; pthread_create(uffd_handler_thread, NULL, uffd_handler_thread_fn,
&uffd_args);
uffd_args);- PER_VCPU_DEBUG("Created uffd thread for HVA range [%p, %p)\n",
hva, hva + len);return 0; } -#define PAGE_SHIFT_4K 12
static void run_test(enum vm_guest_mode mode, bool use_uffd,
useconds_t uffd_delay, uint64_t vcpu_wss)
useconds_t uffd_delay, int vcpus, uint64_t vcpu_wss){
- pthread_t vcpu_thread;
- pthread_t uffd_handler_thread;
- pthread_t *vcpu_threads;
- pthread_t *uffd_handler_threads = NULL;
- struct uffd_handler_args *uffd_args = NULL; struct kvm_vm *vm;
- struct vcpu_thread_args vcpu_args;
- struct vcpu_thread_args *vcpu_args; uint64_t guest_num_pages;
- int vcpu_id; int r;
- /*
* We reserve page table for twice the ammount of memory we intend* to use in the test region for demand paging. Here we do the* calculation with 4K page size which is the smallest so the page* number will be enough for all archs. (e.g., 64K page size guest* will need even less memory for page tables).*/- vm = create_vm(mode, VCPU_ID, (2 * vcpu_wss) >> PAGE_SHIFT_4K,
guest_code);
- vm = create_vm(mode, vcpus, vcpu_wss);
guest_page_size = vm_get_page_size(vm); TEST_ASSERT(vcpu_wss % guest_page_size == 0, "Guest memory size is not guest page size aligned.");
- guest_num_pages = vcpu_wss / guest_page_size;
- guest_num_pages = (vcpus * vcpu_wss) / guest_page_size;
#ifdef __s390x__ /* Round up to multiple of 1M (segment size) */ @@ -316,13 +323,12 @@ static void run_test(enum vm_guest_mode mode, bool use_uffd, */ TEST_ASSERT(guest_num_pages < vm_get_max_gfn(vm), "Requested more guest memory than address space allows.\n"
" guest pages: %lx max gfn: %lx\n",guest_num_pages, vm_get_max_gfn(vm));
" guest pages: %lx max gfn: %lx vcpus: %d wss: %lx]\n",guest_num_pages, vm_get_max_gfn(vm), vcpus, vcpu_wss);host_page_size = getpagesize(); TEST_ASSERT(vcpu_wss % host_page_size == 0, "Guest memory size is not host page size aligned.");
- host_num_pages = vcpu_wss / host_page_size;
guest_test_phys_mem = (vm_get_max_gfn(vm) - guest_num_pages) * guest_page_size; @@ -347,43 +353,102 @@ static void run_test(enum vm_guest_mode mode, bool use_uffd, virt_map(vm, guest_test_virt_mem, guest_test_phys_mem, guest_num_pages * guest_page_size, 0);
- /* Cache the HVA pointer of the region */
- host_test_mem = addr_gpa2hva(vm, (vm_paddr_t)guest_test_phys_mem);
- /* Export the shared variables to the guest */
- sync_global_to_guest(vm, host_page_size);
- sync_global_to_guest(vm, guest_page_size);
- guest_data_prototype = malloc(host_page_size);
- TEST_ASSERT(guest_data_prototype, "Memory allocation failed");
- memset(guest_data_prototype, 0xAB, host_page_size);
- vcpu_threads = malloc(vcpus * sizeof(*vcpu_threads));
- TEST_ASSERT(vcpu_threads, "Memory allocation failed");
if (use_uffd) {
/* Set up user fault fd to handle demand paging requests. */r = setup_demand_paging(vm, &uffd_handler_thread,uffd_delay);if (r < 0)exit(-r);
uffd_handler_threads =malloc(vcpus * sizeof(*uffd_handler_threads));TEST_ASSERT(uffd_handler_threads, "Memory allocation failed");uffd_args = malloc(vcpus * sizeof(*uffd_args));TEST_ASSERT(uffd_args, "Memory allocation failed");
- vcpu_args = malloc(vcpus * sizeof(*vcpu_args));
- TEST_ASSERT(vcpu_args, "Memory allocation failed");
- for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
vm_paddr_t vcpu_gpa;void *vcpu_hva;vm_vcpu_add_default(vm, vcpu_id, guest_code);vcpu_gpa = guest_test_phys_mem + (vcpu_id * vcpu_wss);PER_VCPU_DEBUG("Added VCPU %d with test mem gpa [%lx, %lx)\n",vcpu_id, vcpu_gpa, vcpu_gpa + vcpu_wss);/* Cache the HVA pointer of the region */vcpu_hva = addr_gpa2hva(vm, vcpu_gpa);if (use_uffd) {/** Set up user fault fd to handle demand paging* requests.*/r = setup_demand_paging(vm,&uffd_handler_threads[vcpu_id],uffd_delay, &uffd_args[vcpu_id],vcpu_hva, vcpu_wss);if (r < 0)exit(-r);}#ifdef __x86_64__
- vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
vcpu_set_cpuid(vm, vcpu_id, kvm_get_supported_cpuid());#endif
- /* Export the shared variables to the guest */
- sync_global_to_guest(vm, host_page_size);
- sync_global_to_guest(vm, guest_page_size);
vcpu_args[vcpu_id].vm = vm;vcpu_args[vcpu_id].vcpu_id = vcpu_id;vcpu_args[vcpu_id].gva = guest_test_virt_mem +(vcpu_id * vcpu_wss);vcpu_args[vcpu_id].pages = vcpu_wss / guest_page_size;- }
- DEBUG("Finished creating vCPUs and starting uffd threads\n");
- for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
pthread_create(&vcpu_threads[vcpu_id], NULL, vcpu_worker,&vcpu_args[vcpu_id]);- }
- DEBUG("Started all vCPUs\n");
- vcpu_args.vm = vm;
- vcpu_args.vcpu_id = VCPU_ID;
- vcpu_args.gva = guest_test_virt_mem;
- vcpu_args.pages = guest_num_pages;
- pthread_create(&vcpu_thread, NULL, vcpu_worker, &vcpu_args);
- /* Wait for the vcpu threads to quit */
- for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
pthread_join(vcpu_threads[vcpu_id], NULL);PER_VCPU_DEBUG("Joined thread for vCPU %d\n", vcpu_id);- }
- /* Wait for the vcpu thread to quit */
- pthread_join(vcpu_thread, NULL);
- DEBUG("All vCPU threads joined\n");
if (use_uffd) {
/* Tell the user fault fd handler thread to quit */
/* Tell the user fault fd handler threads to quit */
pthread_join(uffd_handler_thread, NULL);
for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++)pthread_join(uffd_handler_threads[vcpu_id], NULL);ucall_uninit(vm); kvm_vm_free(vm);
- free(guest_data_prototype);
- free(vcpu_threads);
- if (use_uffd) {
free(uffd_handler_threads);free(uffd_args);- }
- free(vcpu_args);
} struct vm_guest_mode_params { @@ -404,7 +469,7 @@ static void help(char *name) puts(""); printf("usage: %s [-h] [-m mode] [-u] [-d uffd_delay_usec]\n"
" [-b bytes test memory]\n", name);
" [-b bytes test memory] [-v vcpus]\n", name);@@ -419,6 +484,7 @@ static void help(char *name) " FD handler to simulate demand paging\n" " overheads. Ignored without -u.\n"); printf(" -b: specify the working set size, in bytes for each vCPU.\n");
- printf(" -v: specify the number of vCPUs to run.\n"); puts(""); exit(0);
} @@ -427,6 +493,7 @@ int main(int argc, char *argv[]) { bool mode_selected = false; uint64_t vcpu_wss = DEFAULT_GUEST_TEST_MEM_SIZE;
- int vcpus = 1; unsigned int mode; int opt, i; bool use_uffd = false;
@@ -439,7 +506,7 @@ int main(int argc, char *argv[]) vm_guest_mode_params_init(VM_MODE_P40V48_4K, true, true); #endif
- while ((opt = getopt(argc, argv, "hm:ud:b:")) != -1) {
- while ((opt = getopt(argc, argv, "hm:ud:b:v:")) != -1) { switch (opt) { case 'm': if (!mode_selected) {
@@ -462,6 +529,12 @@ int main(int argc, char *argv[]) break; case 'b': vcpu_wss = strtoull(optarg, NULL, 0);
break;
There's that missing break. It's good to test each patch to ensure bisectability.
case 'v':vcpus = atoi(optarg);TEST_ASSERT(vcpus > 0,"Must have a positive number of vCPUs");break;@@ -475,7 +548,7 @@ int main(int argc, char *argv[]) TEST_ASSERT(vm_guest_mode_params[i].supported, "Guest mode ID %d (%s) not supported.", i, vm_guest_mode_string(i));
run_test(i, use_uffd, uffd_delay, vcpu_wss);
run_test(i, use_uffd, uffd_delay, vcpus, vcpu_wss);return 0; -- 2.24.1.735.g03f4e72817-goog
Thanks, drew