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[Qemu-devel] [PULL 23/36] util/qemu-timer: refactor deadline calculation
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PULL 23/36] util/qemu-timer: refactor deadline calculation for external timers |
Date: |
Tue, 20 Aug 2019 08:59:42 +0200 |
From: Pavel Dovgalyuk <address@hidden>
icount-based record/replay uses qemu_clock_deadline_ns_all to measure
the period until vCPU may be interrupted.
This function takes in account the virtual timers, because they belong
to the virtual devices that may generate interrupt request or affect
the virtual machine state.
However, there are a subset of virtual timers, that are marked with
'external' flag. These do not change the virtual machine state and
only based on virtual clock. Calculating the deadling using the external
timers breaks the determinism, because they do not belong to the replayed
part of the virtual machine.
This patch fixes the deadline calculation for this case by adding
new parameter for skipping the external timers when it is needed.
Signed-off-by: Pavel Dovgalyuk <address@hidden>
--
v2 changes:
- added new parameter for timer attribute mask
Message-Id:
<156404426682.18669.17014100602930969222.stgit@pasha-Precision-3630-Tower>
Signed-off-by: Paolo Bonzini <address@hidden>
---
cpus.c | 17 ++++++++++++-----
include/qemu/timer.h | 8 ++++++--
qtest.c | 3 ++-
tests/ptimer-test-stubs.c | 4 ++--
tests/ptimer-test.c | 6 ++++--
util/qemu-timer.c | 30 +++++++++++++++++++++++++++---
6 files changed, 53 insertions(+), 15 deletions(-)
diff --git a/cpus.c b/cpus.c
index 927a00a..a7120ff 100644
--- a/cpus.c
+++ b/cpus.c
@@ -553,7 +553,8 @@ void qtest_clock_warp(int64_t dest)
assert(qtest_enabled());
aio_context = qemu_get_aio_context();
while (clock < dest) {
- int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
+ int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
+ QEMU_TIMER_ATTR_ALL);
int64_t warp = qemu_soonest_timeout(dest - clock, deadline);
seqlock_write_lock(&timers_state.vm_clock_seqlock,
@@ -613,7 +614,8 @@ void qemu_start_warp_timer(void)
/* We want to use the earliest deadline from ALL vm_clocks */
clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT);
- deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
+ deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
+ ~QEMU_TIMER_ATTR_EXTERNAL);
if (deadline < 0) {
static bool notified;
if (!icount_sleep && !notified) {
@@ -1349,7 +1351,12 @@ static int64_t tcg_get_icount_limit(void)
int64_t deadline;
if (replay_mode != REPLAY_MODE_PLAY) {
- deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
+ /*
+ * Include all the timers, because they may need an attention.
+ * Too long CPU execution may create unnecessary delay in UI.
+ */
+ deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
+ QEMU_TIMER_ATTR_ALL);
/* Maintain prior (possibly buggy) behaviour where if no deadline
* was set (as there is no QEMU_CLOCK_VIRTUAL timer) or it is more than
@@ -1370,8 +1377,8 @@ static void handle_icount_deadline(void)
{
assert(qemu_in_vcpu_thread());
if (use_icount) {
- int64_t deadline =
- qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
+ int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
+ QEMU_TIMER_ATTR_ALL);
if (deadline == 0) {
/* Wake up other AioContexts. */
diff --git a/include/qemu/timer.h b/include/qemu/timer.h
index 5bcab93..85bc6eb 100644
--- a/include/qemu/timer.h
+++ b/include/qemu/timer.h
@@ -62,13 +62,15 @@ typedef enum {
* The following attributes are available:
*
* QEMU_TIMER_ATTR_EXTERNAL: drives external subsystem
+ * QEMU_TIMER_ATTR_ALL: mask for all existing attributes
*
* Timers with this attribute do not recorded in rr mode, therefore it could be
* used for the subsystems that operate outside the guest core. Applicable only
* with virtual clock type.
*/
-#define QEMU_TIMER_ATTR_EXTERNAL BIT(0)
+#define QEMU_TIMER_ATTR_EXTERNAL ((int)BIT(0))
+#define QEMU_TIMER_ATTR_ALL 0xffffffff
typedef struct QEMUTimerList QEMUTimerList;
@@ -177,6 +179,8 @@ bool qemu_clock_use_for_deadline(QEMUClockType type);
/**
* qemu_clock_deadline_ns_all:
* @type: the clock type
+ * @attr_mask: mask for the timer attributes that are included
+ * in deadline calculation
*
* Calculate the deadline across all timer lists associated
* with a clock (as opposed to just the default one)
@@ -184,7 +188,7 @@ bool qemu_clock_use_for_deadline(QEMUClockType type);
*
* Returns: time until expiry in nanoseconds or -1
*/
-int64_t qemu_clock_deadline_ns_all(QEMUClockType type);
+int64_t qemu_clock_deadline_ns_all(QEMUClockType type, int attr_mask);
/**
* qemu_clock_get_main_loop_timerlist:
diff --git a/qtest.c b/qtest.c
index 15e27e9..4e20856 100644
--- a/qtest.c
+++ b/qtest.c
@@ -655,7 +655,8 @@ static void qtest_process_command(CharBackend *chr, gchar
**words)
int ret = qemu_strtoi64(words[1], NULL, 0, &ns);
g_assert(ret == 0);
} else {
- ns = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
+ ns = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
+ QEMU_TIMER_ATTR_ALL);
}
qtest_clock_warp(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + ns);
qtest_send_prefix(chr);
diff --git a/tests/ptimer-test-stubs.c b/tests/ptimer-test-stubs.c
index 54b3fd2..ed393d9 100644
--- a/tests/ptimer-test-stubs.c
+++ b/tests/ptimer-test-stubs.c
@@ -88,9 +88,9 @@ int64_t qemu_clock_get_ns(QEMUClockType type)
return ptimer_test_time_ns;
}
-int64_t qemu_clock_deadline_ns_all(QEMUClockType type)
+int64_t qemu_clock_deadline_ns_all(QEMUClockType type, int attr_mask)
{
- QEMUTimerList *timer_list = main_loop_tlg.tl[type];
+ QEMUTimerList *timer_list = main_loop_tlg.tl[QEMU_CLOCK_VIRTUAL];
QEMUTimer *t = timer_list->active_timers.next;
int64_t deadline = -1;
diff --git a/tests/ptimer-test.c b/tests/ptimer-test.c
index b30aad0..5b20e91 100644
--- a/tests/ptimer-test.c
+++ b/tests/ptimer-test.c
@@ -50,13 +50,15 @@ static void ptimer_test_set_qemu_time_ns(int64_t ns)
static void qemu_clock_step(uint64_t ns)
{
- int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
+ int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
+ QEMU_TIMER_ATTR_ALL);
int64_t advanced_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + ns;
while (deadline != -1 && deadline <= advanced_time) {
ptimer_test_set_qemu_time_ns(deadline);
ptimer_test_expire_qemu_timers(deadline, QEMU_CLOCK_VIRTUAL);
- deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
+ deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
+ QEMU_TIMER_ATTR_ALL);
}
ptimer_test_set_qemu_time_ns(advanced_time);
diff --git a/util/qemu-timer.c b/util/qemu-timer.c
index b73041d..dcaaac7 100644
--- a/util/qemu-timer.c
+++ b/util/qemu-timer.c
@@ -248,14 +248,38 @@ int64_t timerlist_deadline_ns(QEMUTimerList *timer_list)
* ignore whether or not the clock should be used in deadline
* calculations.
*/
-int64_t qemu_clock_deadline_ns_all(QEMUClockType type)
+int64_t qemu_clock_deadline_ns_all(QEMUClockType type, int attr_mask)
{
int64_t deadline = -1;
+ int64_t delta;
+ int64_t expire_time;
+ QEMUTimer *ts;
QEMUTimerList *timer_list;
QEMUClock *clock = qemu_clock_ptr(type);
+
+ if (!clock->enabled) {
+ return -1;
+ }
+
QLIST_FOREACH(timer_list, &clock->timerlists, list) {
- deadline = qemu_soonest_timeout(deadline,
- timerlist_deadline_ns(timer_list));
+ qemu_mutex_lock(&timer_list->active_timers_lock);
+ ts = timer_list->active_timers;
+ /* Skip all external timers */
+ while (ts && (ts->attributes & ~attr_mask)) {
+ ts = ts->next;
+ }
+ if (!ts) {
+ qemu_mutex_unlock(&timer_list->active_timers_lock);
+ continue;
+ }
+ expire_time = ts->expire_time;
+ qemu_mutex_unlock(&timer_list->active_timers_lock);
+
+ delta = expire_time - qemu_clock_get_ns(type);
+ if (delta <= 0) {
+ delta = 0;
+ }
+ deadline = qemu_soonest_timeout(deadline, delta);
}
return deadline;
}
--
1.8.3.1
- [Qemu-devel] [PULL 19/36] timer: last, remove last bits of last, (continued)
- [Qemu-devel] [PULL 19/36] timer: last, remove last bits of last, Paolo Bonzini, 2019/08/20
- [Qemu-devel] [PULL 20/36] kconfig: do not select VMMOUSE, Paolo Bonzini, 2019/08/20
- [Qemu-devel] [PULL 18/36] replay: Remove host_clock_last, Paolo Bonzini, 2019/08/20
- [Qemu-devel] [PULL 25/36] replay: refine replay-time module, Paolo Bonzini, 2019/08/20
- [Qemu-devel] [PULL 29/36] cpus-common: nuke finish_safe_work, Paolo Bonzini, 2019/08/20
- [Qemu-devel] [PULL 27/36] icount: clean up cpu_can_io at the entry to the block, Paolo Bonzini, 2019/08/20
- [Qemu-devel] [PULL 36/36] x86: Intel AVX512_BF16 feature enabling, Paolo Bonzini, 2019/08/20
- [Qemu-devel] [PULL 28/36] icount: remove unnecessary gen_io_end calls, Paolo Bonzini, 2019/08/20
- [Qemu-devel] [PULL 26/36] replay: rename step-related variables and functions, Paolo Bonzini, 2019/08/20
- [Qemu-devel] [PULL 32/36] HACKING: Document 'struct' keyword usage, Paolo Bonzini, 2019/08/20
- [Qemu-devel] [PULL 23/36] util/qemu-timer: refactor deadline calculation for external timers,
Paolo Bonzini <=
- [Qemu-devel] [PULL 33/36] migration: do not rom_reset() during incoming migration, Paolo Bonzini, 2019/08/20
- [Qemu-devel] [PULL 34/36] test-bitmap: test set 1 bit case for bitmap_set, Paolo Bonzini, 2019/08/20
- [Qemu-devel] [PULL 35/36] scsi: lsi: exit infinite loop while executing script (CVE-2019-12068), Paolo Bonzini, 2019/08/20
- Re: [Qemu-devel] [PULL 00/36] QEMU patches for 2018-08-20, no-reply, 2019/08/20
- Re: [Qemu-devel] [PULL 00/36] QEMU patches for 2018-08-20, Peter Maydell, 2019/08/20
- Re: [Qemu-devel] [PULL 00/36] QEMU patches for 2018-08-20, no-reply, 2019/08/20