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aio / timers: Use all timerlists in icount warp calculations

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Notify all timerlists derived from vm_clock in icount warp
calculations.

When calculating timer delay based on vm_clock deadline, use
all timerlists.

For compatibility, maintain an apparent bug where when using
icount, if no vm_clock timer was set, qemu_clock_deadline
would return INT32_MAX and always set an icount clock expiry
about 2 seconds ahead.

NB: thread safety - when different timerlists sit on different
threads, this will need some locking.

Signed-off-by: Alex Bligh <alex@alex.org.uk>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Alex Bligh 2013-08-21 16:02:57 +01:00 • committed by Stefan Hajnoczi
parent a3a726ae09
commit ac70aafc28
4 changed files with 67 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

46
cpus.c
View file

@ -267,7 +267,7 @@ static void icount_warp_rt(void *opaque)
qemu_icount_bias += MIN(warp_delta, delta);
}
if (qemu_clock_expired(vm_clock)) {
qemu_notify_event();
qemu_clock_notify(vm_clock);
}
}
vm_clock_warp_start = -1;
@ -278,13 +278,13 @@ void qtest_clock_warp(int64_t dest)
int64_t clock = qemu_get_clock_ns(vm_clock);
assert(qtest_enabled());
while (clock < dest) {
int64_t deadline = qemu_clock_deadline(vm_clock);
int64_t deadline = qemu_clock_deadline_ns_all(vm_clock);
int64_t warp = MIN(dest - clock, deadline);
qemu_icount_bias += warp;
qemu_run_timers(vm_clock);
clock = qemu_get_clock_ns(vm_clock);
}
qemu_notify_event();
qemu_clock_notify(vm_clock);
}
void qemu_clock_warp(QEMUClock *clock)
@ -319,7 +319,18 @@ void qemu_clock_warp(QEMUClock *clock)
}
vm_clock_warp_start = qemu_get_clock_ns(rt_clock);
deadline = qemu_clock_deadline(vm_clock);
/* We want to use the earliest deadline from ALL vm_clocks */
deadline = qemu_clock_deadline_ns_all(vm_clock);
/* Maintain prior (possibly buggy) behaviour where if no deadline
* was set (as there is no vm_clock timer) or it is more than
* INT32_MAX nanoseconds ahead, we still use INT32_MAX
* nanoseconds.
*/
if ((deadline < 0) || (deadline > INT32_MAX)) {
deadline = INT32_MAX;
}
if (deadline > 0) {
/*
* Ensure the vm_clock proceeds even when the virtual CPU goes to
@ -338,8 +349,8 @@ void qemu_clock_warp(QEMUClock *clock)
* packets continuously instead of every 100ms.
*/
qemu_mod_timer(icount_warp_timer, vm_clock_warp_start + deadline);
} else {
qemu_notify_event();
} else if (deadline == 0) {
qemu_clock_notify(vm_clock);
}
}
@ -866,8 +877,13 @@ static void *qemu_tcg_cpu_thread_fn(void *arg)
while (1) {
tcg_exec_all();
if (use_icount && qemu_clock_deadline(vm_clock) <= 0) {
qemu_notify_event();
if (use_icount) {
int64_t deadline = qemu_clock_deadline_ns_all(vm_clock);
if (deadline == 0) {
qemu_clock_notify(vm_clock);
}
}
qemu_tcg_wait_io_event();
}
@ -1145,11 +1161,23 @@ static int tcg_cpu_exec(CPUArchState *env)
#endif
if (use_icount) {
int64_t count;
int64_t deadline;
int decr;
qemu_icount -= (env->icount_decr.u16.low + env->icount_extra);
env->icount_decr.u16.low = 0;
env->icount_extra = 0;
count = qemu_icount_round(qemu_clock_deadline(vm_clock));
deadline = qemu_clock_deadline_ns_all(vm_clock);
/* Maintain prior (possibly buggy) behaviour where if no deadline
* was set (as there is no vm_clock timer) or it is more than
* INT32_MAX nanoseconds ahead, we still use INT32_MAX
* nanoseconds.
*/
if ((deadline < 0) || (deadline > INT32_MAX)) {
deadline = INT32_MAX;
}
count = qemu_icount_round(deadline);
qemu_icount += count;
decr = (count > 0xffff) ? 0xffff : count;
count -= decr;