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gettimeofday(): an implementation based on CPU invariant TSC support

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This commit is contained in:
Balazs Gerofi
2015-08-24 23:41:31 +02:00
parent b8f166e608
commit 9ae5bcf46e
8 changed files with 193 additions and 33 deletions
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146
kernel/syscall.c
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@@ -105,6 +105,7 @@ int patch_process_vm(struct process_vm *, void *, const void *, size_t);
void do_setpgid(int, int);
extern long alloc_debugreg(struct process *proc);
extern int num_processors;
extern unsigned long ihk_mc_get_ns_per_tsc(void);
static int ptrace_detach(int pid, int data);
int prepare_process_ranges_args_envs(struct process *proc,
@@ -3505,38 +3506,47 @@ SYSCALL_DECLARE(futex)
(unsigned long)uaddr, op, val, utime, uaddr2, val3, *uaddr);
if (utime && (op == FUTEX_WAIT_BITSET || op == FUTEX_WAIT)) {
struct syscall_request request IHK_DMA_ALIGN;
struct timeval tv_now;
request.number = n;
unsigned long __phys;
if (!gettime_local_support) {
struct syscall_request request IHK_DMA_ALIGN;
struct timeval tv_now;
request.number = n;
unsigned long __phys;
dkprintf("futex,utime and FUTEX_WAIT_*, uaddr=%lx, []=%x\n", (unsigned long)uaddr, *uaddr);
dkprintf("futex,utime and FUTEX_WAIT_*, uaddr=%lx, []=%x\n", (unsigned long)uaddr, *uaddr);
if (ihk_mc_pt_virt_to_phys(cpu_local_var(current)->vm->page_table,
(void *)&tv_now, &__phys)) {
return -EFAULT;
if (ihk_mc_pt_virt_to_phys(cpu_local_var(current)->vm->page_table,
(void *)&tv_now, &__phys)) {
return -EFAULT;
}
request.args[0] = __phys;
int r = do_syscall(&request, ihk_mc_get_processor_id(), 0);
if (r < 0) {
return -EFAULT;
}
dkprintf("futex, FUTEX_WAIT_*, arg3 != NULL, pc=%lx\n", (unsigned long)ihk_mc_syscall_pc(ctx));
dkprintf("now->tv_sec=%016ld,tv_nsec=%016ld\n", tv_now.tv_sec, tv_now.tv_usec * 1000);
dkprintf("utime->tv_sec=%016ld,tv_nsec=%016ld\n", utime->tv_sec, utime->tv_nsec);
unsigned long nsec_timeout = ((long)utime->tv_sec * 1000000000ULL)
+ utime->tv_nsec;
long nsec_now = ((long)tv_now.tv_sec * 1000000000ULL) +
tv_now.tv_usec * 1000;
long diff_nsec = nsec_timeout - nsec_now;
timeout = (diff_nsec / 1000) * 1100; // (usec * 1.1GHz)
}
/* Compute timeout based on TSC/nanosec ratio */
else {
unsigned long nsec_timeout = ((long)utime->tv_sec * 1000000000ULL)
+ utime->tv_nsec;
request.args[0] = __phys;
int r = do_syscall(&request, ihk_mc_get_processor_id(), 0);
if (r < 0) {
return -EFAULT;
timeout = nsec_timeout * 1000 / ihk_mc_get_ns_per_tsc();
dkprintf("futex timeout: %lu\n", timeout);
}
dkprintf("futex, FUTEX_WAIT_*, arg3 != NULL, pc=%lx\n", (unsigned long)ihk_mc_syscall_pc(ctx));
dkprintf("now->tv_sec=%016ld,tv_nsec=%016ld\n", tv_now.tv_sec, tv_now.tv_usec * 1000);
dkprintf("utime->tv_sec=%016ld,tv_nsec=%016ld\n", utime->tv_sec, utime->tv_nsec);
long nsec_now = ((long)tv_now.tv_sec * 1000000000ULL) +
tv_now.tv_usec * 1000;
long nsec_timeout = ((long)utime->tv_sec * 1000000000ULL) +
utime->tv_nsec * 1;
long diff_nsec = nsec_timeout - nsec_now;
timeout = (diff_nsec / 1000) * 1100; // (usec * 1.1GHz)
dkprintf("futex timeout: %lu\n", timeout);
}
/* Requeue parameter in 'utime' if op == FUTEX_CMP_REQUEUE.
@@ -4913,6 +4923,88 @@ SYSCALL_DECLARE(get_cpu_id)
return ihk_mc_get_processor_id();
}
void __update_time_from_tsc_delta(unsigned long *tv_sec,
unsigned long *tv_nsec,
unsigned long tsc_delta)
{
unsigned long ns_delta = tsc_delta * ihk_mc_get_ns_per_tsc() / 1000;
*tv_sec += (ns_delta / NS_PER_SEC);
*tv_nsec += (ns_delta % NS_PER_SEC);
if (*tv_nsec > NS_PER_SEC) {
*tv_nsec -= NS_PER_SEC;
++*tv_sec;
}
}
void update_cpu_local_time(void)
{
unsigned long tsc = rdtsc();
__update_time_from_tsc_delta(
&cpu_local_var(tv_sec),
&cpu_local_var(tv_nsec),
tsc - cpu_local_var(last_tsc));
cpu_local_var(last_tsc) = tsc;
}
SYSCALL_DECLARE(gettimeofday)
{
struct timeval *tv = (struct timeval *)ihk_mc_syscall_arg0(ctx);
struct syscall_request request IHK_DMA_ALIGN;
/* Do it locally if supported */
if (gettime_local_support) {
update_cpu_local_time();
tv->tv_sec = cpu_local_var(tv_sec);
tv->tv_usec = cpu_local_var(tv_nsec) / 1000;
dkprintf("gettimeofday(): \n");
return 0;
}
/* Otherwise offload */
request.number = __NR_gettimeofday;
request.args[0] = (unsigned long)tv;
return do_syscall(&request, ihk_mc_get_processor_id(), 0);
}
SYSCALL_DECLARE(nanosleep)
{
struct timespec *tv = (struct timespec *)ihk_mc_syscall_arg0(ctx);
struct timespec *rem = (struct timespec *)ihk_mc_syscall_arg0(ctx);
struct syscall_request request IHK_DMA_ALIGN;
/* Do it locally if supported */
if (gettime_local_support) {
unsigned long nanosecs = tv->tv_sec * NS_PER_SEC + tv->tv_nsec;
unsigned long tscs = nanosecs * 1000 / ihk_mc_get_ns_per_tsc();
unsigned long ts = rdtsc();
/* Spin wait */
while (rdtsc() - ts < tscs)
cpu_pause();
rem->tv_sec = 0;
rem->tv_nsec = 0;
return 0;
}
/* Otherwise offload */
request.number = __NR_nanosleep;
request.args[0] = (unsigned long)tv;
request.args[0] = (unsigned long)rem;
return do_syscall(&request, ihk_mc_get_processor_id(), 0);
}
SYSCALL_DECLARE(sched_yield)
{
schedule();