Commit 83f6e109 authored by Ben Gardon's avatar Ben Gardon Committed by Paolo Bonzini
Browse files

KVM: selftests: Cache binary stats metadata for duration of test 



In order to improve performance across multiple reads of VM stats, cache
the stats metadata in the VM struct.

Signed-off-by: default avatarBen Gardon <bgardon@google.com>
Message-Id: <20220613212523.3436117-11-bgardon@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent b774da3f

tools/testing/selftests/kvm/include/kvm_util_base.h

+5 −0
Original line number Diff line number Diff line
@@ -84,6 +84,11 @@ struct kvm_vm { 
	vm_vaddr_t idt;

	vm_vaddr_t handlers;

	uint32_t dirty_ring_size;



	/* Cache of information for binary stats interface */

	int stats_fd;

	struct kvm_stats_header stats_header;

	struct kvm_stats_desc *stats_desc;

};

tools/testing/selftests/kvm/lib/kvm_util.c

+17 −15
Original line number Diff line number Diff line
@@ -547,6 +547,12 @@ void kvm_vm_free(struct kvm_vm *vmp) 
	if (vmp == NULL)

		return;



	/* Free cached stats metadata and close FD */

	if (vmp->stats_fd) {

		free(vmp->stats_desc);

		close(vmp->stats_fd);

	}



	/* Free userspace_mem_regions. */

	hash_for_each_safe(vmp->regions.slot_hash, ctr, node, region, slot_node)

		__vm_mem_region_delete(vmp, region, false);
@@ -1935,32 +1941,28 @@ void read_stat_data(int stats_fd, struct kvm_stats_header *header, 
void __vm_get_stat(struct kvm_vm *vm, const char *stat_name, uint64_t *data,

		   size_t max_elements)

{

	struct kvm_stats_desc *stats_desc;

	struct kvm_stats_header header;

	struct kvm_stats_desc *desc;

	size_t size_desc;

	int stats_fd;

	int i;



	stats_fd = vm_get_stats_fd(vm);



	read_stats_header(stats_fd, &header);



	stats_desc = read_stats_descriptors(stats_fd, &header);

	if (!vm->stats_fd) {

		vm->stats_fd = vm_get_stats_fd(vm);

		read_stats_header(vm->stats_fd, &vm->stats_header);

		vm->stats_desc = read_stats_descriptors(vm->stats_fd,

							&vm->stats_header);

	}



	size_desc = get_stats_descriptor_size(&header);

	size_desc = get_stats_descriptor_size(&vm->stats_header);



	for (i = 0; i < header.num_desc; ++i) {

		desc = (void *)stats_desc + (i * size_desc);

	for (i = 0; i < vm->stats_header.num_desc; ++i) {

		desc = (void *)vm->stats_desc + (i * size_desc);



		if (strcmp(desc->name, stat_name))

			continue;



		read_stat_data(stats_fd, &header, desc, data, max_elements);

		read_stat_data(vm->stats_fd, &vm->stats_header, desc,

			       data, max_elements);



		break;

	}



	free(stats_desc);

	close(stats_fd);

}