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add memory barriers and an option to enable kernel-based deduplication

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This commit is contained in:
Stefan Lankes 2017-04-24 11:26:35 +02:00
parent cb5787256d
commit 5111d7c7e8
1 changed files with 23 additions and 6 deletions
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29
tools/uhyve.c
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@ -166,6 +166,10 @@ static __thread struct kvm_run *run = NULL;
static __thread int vcpufd = -1;
static __thread uint32_t cpuid = 0;
static inline void mb(void) {
__asm__ volatile("mfence":::"memory");
}
static uint64_t memparse(const char *ptr)
{
// local pointer to end of parsed string
@ -872,6 +876,7 @@ static int vcpu_init(void)
kvm_ioctl(vcpufd, KVM_GET_REGS, &regs);
//show_registers(cpuid, &regs, &sregs);
//pthread_mutex_unlock(&kvm_lock);
mb();
} else {
// be sure that the multiprocessor is runable
kvm_ioctl(vcpufd, KVM_SET_MP_STATE, &mp_state);
@ -969,6 +974,9 @@ static void save_cpu_state(void)
static void sigusr_handler(int signum)
{
// memory barrier
mb();
pthread_barrier_wait(&barrier);
save_cpu_state();
@ -1070,12 +1078,17 @@ int uhyve_init(char *path)
mprotect(guest_mem + KVM_32BIT_GAP_START, KVM_32BIT_GAP_SIZE, PROT_NONE);
}
/*
* The KSM feature is intended for applications that generate
* many instances of the same data (e.g., virtualization systems
* such as KVM). It can consume a lot of processing power!
*/
//madvise(guest_mem, guest_size, MADV_MERGEABLE);
char* merge = getenv("HERMIT_MERGEABLE");
if (merge && (strcmp(merge, "0") != 0)) {
/*
* The KSM feature is intended for applications that generate
* many instances of the same data (e.g., virtualization systems
* such as KVM). It can consume a lot of processing power!
*/
madvise(guest_mem, guest_size, MADV_MERGEABLE);
if (verbose)
fprintf(stderr, "VM uses KSN feature \"mergeable\" to reduce the memory footprint.\n");
}
struct kvm_userspace_memory_region kvm_region = {
.slot = 0,
@ -1121,6 +1134,7 @@ int uhyve_init(char *path)
pthread_barrier_init(&barrier, NULL, ncores);
cpuid = 0;
mb();
// create first CPU, it will be the boot processor by default
return vcpu_init();
@ -1144,6 +1158,9 @@ static void timer_handler(int signum)
if (vcpu_threads[i] != pthread_self())
pthread_kill(vcpu_threads[i], SIGUSR1);
// memory barrier
mb();
pthread_barrier_wait(&barrier);
save_cpu_state();