From c5634b6e2cbdd6d37a056dca6ca87da0ad031525 Mon Sep 17 00:00:00 2001
From: Nadav Har'El <nyh@cloudius-systems.com>
Date: Sun, 26 Jan 2014 15:34:35 +0200
Subject: [PATCH] clock: Support monotonic clock in timerfd
Switch the timerfd to use std::chrono types, and add support also for the
monotonic clock.
Fixes #142.
Reviewed-by: Glauber Costa <glommer@cloudius-systems.com>
Signed-off-by: Nadav Har'El <nyh@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
---
libc/timerfd.cc | 53 ++++++++++++++++++++++++++++++++++++++++---------
1 file changed, 44 insertions(+), 9 deletions(-)
diff --git a/libc/timerfd.cc b/libc/timerfd.cc
index da98f0940..ab67c08ef 100644
--- a/libc/timerfd.cc
+++ b/libc/timerfd.cc
@@ -49,12 +49,19 @@ private:
bool _wakeup_thread_exit = false;
condvar _blocked_reader;
void wakeup_thread_func();
+
+ // Which clock to use to interpret s64 times.
+ int _clockid;
+ void set_timer(sched::timer &tmr, s64 time);
+public:
+ s64 time_now() const;
};
timerfd::timerfd(int clockid, int oflags)
: special_file(FREAD | oflags, DTYPE_UNSPEC),
_wakeup_thread(
- [&] { wakeup_thread_func(); }, sched::thread::attr().stack(4096))
+ [&] { wakeup_thread_func(); }, sched::thread::attr().stack(4096)),
+ _clockid(clockid)
{
_wakeup_thread.start();
}
@@ -67,13 +74,43 @@ timerfd::~timerfd() {
_wakeup_thread.join();
}
+void timerfd::set_timer(sched::timer &tmr, s64 t)
+{
+ using namespace osv::clock;
+ switch(_clockid) {
+ case CLOCK_REALTIME:
+ tmr.set(wall::time_point(std::chrono::nanoseconds(t)));
+ break;
+ case CLOCK_MONOTONIC:
+ tmr.set(uptime::time_point(std::chrono::nanoseconds(t)));
+ break;
+ default:
+ assert(false);
+ }
+}
+
+s64 timerfd::time_now() const
+{
+ using namespace std::chrono;
+ switch(_clockid) {
+ case CLOCK_REALTIME:
+ return duration_cast<nanoseconds>(
+ osv::clock::wall::now().time_since_epoch()).count();
+ case CLOCK_MONOTONIC:
+ return duration_cast<nanoseconds>(
+ osv::clock::uptime::now().time_since_epoch()).count();
+ default:
+ assert(false);
+ }
+}
+
void timerfd::wakeup_thread_func()
{
sched::timer tmr(*sched::thread::current());
WITH_LOCK(_mutex) {
while (!_wakeup_thread_exit) {
if (_wakeup_due != 0) {
- tmr.set(_wakeup_due);
+ set_timer(tmr, _wakeup_due);
_wakeup_change_cond.wait(_mutex, &tmr);
if (tmr.expired()) {
_wakeup_due = 0;
@@ -109,7 +146,7 @@ void timerfd::get(s64 &expiration, s64 &interval) const
if (!_interval) {
expiration = 0;
} else {
- auto now = nanotime();
+ auto now = time_now();
u64 count = (now - _expiration) / _interval;
expiration = _expiration + (count+1) * _interval;
}
@@ -157,7 +194,7 @@ int timerfd::read(uio *data, int flags)
ret = 1;
_expiration = 0;
} else {
- auto now = nanotime();
+ auto now = time_now();
// set next wakeup for the next multiple of interval from
// _expiration which is after "now".
assert (now >= _expiration);
@@ -195,10 +232,8 @@ int timerfd::close()
int timerfd_create(int clockid, int flags) {
switch (clockid) {
- case CLOCK_MONOTONIC:
- WARN_ONCE("timerfd_create() does not yet support CLOCK_MONOTONIC\n");
- return libc_error(EINVAL);
case CLOCK_REALTIME:
+ case CLOCK_MONOTONIC:
// fine.
break;
default:
@@ -232,7 +267,7 @@ int timerfd_settime(int fd, int flags, const itimerspec *newval,
}
s64 expiration, interval;
- s64 now = nanotime();
+ auto now = tf->time_now();
if (oldval) {
tf->get(expiration, interval);
if (expiration) {
@@ -269,7 +304,7 @@ int timerfd_gettime(int fd, itimerspec *val)
}
s64 expiration, interval;
- s64 now = nanotime();
+ auto now = tf->time_now();
tf->get(expiration, interval);
if (expiration) {
// timerfd_gettime() wants relative time
--
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