Enabling the I/O thread by default seems like an important part of declaring
1.0. Besides allowing true SMP support with KVM, the I/O thread means that the
TCG VCPU doesn't have to multiplex itself with the I/O dispatch routines which
currently requires a (racey) signal based alarm system.
I know there have been concerns about performance. I think so far the ones that
have come up (virtio-net) are most likely due to secondary reasons like
decreased batching.
I think we ought to force enabling I/O thread early in 1.0 development and
commit to resolving any lingering issues.
Signed-off-by: Anthony Liguori <aligu...@us.ibm.com>
---
configure | 13 -----
cpus.c | 143 ----------------------------------------------------------
hw/qxl.c | 4 --
kvm-all.c | 2 +-
qemu-timer.c | 53 ---------------------
vl.c | 17 -------
6 files changed, 1 insertions(+), 231 deletions(-)
diff --git a/configure b/configure
index 234a4c5..ef8d7ae 100755
--- a/configure
+++ b/configure
@@ -165,7 +165,6 @@ darwin_user="no"
bsd_user="no"
guest_base=""
uname_release=""
-io_thread="no"
mixemu="no"
aix="no"
blobs="yes"
@@ -722,8 +721,6 @@ for opt do
;;
--enable-attr) attr="yes"
;;
- --enable-io-thread) io_thread="yes"
- ;;
--disable-blobs) blobs="no"
;;
--with-pkgversion=*) pkgversion=" ($optarg)"
@@ -2159,12 +2156,6 @@ EOF
if compile_prog "" "" ; then
signalfd=yes
-elif test "$kvm" = "yes" -a "$io_thread" != "yes"; then
- echo
- echo "ERROR: Host kernel lacks signalfd() support,"
- echo "but KVM depends on it when the IO thread is disabled."
- echo
- exit 1
fi
# check if eventfd is supported
@@ -2711,7 +2702,6 @@ echo "NPTL support $nptl"
echo "GUEST_BASE $guest_base"
echo "PIE user targets $user_pie"
echo "vde support $vde"
-echo "IO thread $io_thread"
echo "Linux AIO support $linux_aio"
echo "ATTR/XATTR support $attr"
echo "Install blobs $blobs"
@@ -2969,9 +2959,6 @@ if test "$xen" = "yes" ; then
echo "CONFIG_XEN_BACKEND=y" >> $config_host_mak
echo "CONFIG_XEN_CTRL_INTERFACE_VERSION=$xen_ctrl_version" >>
$config_host_mak
fi
-if test "$io_thread" = "yes" ; then
- echo "CONFIG_IOTHREAD=y" >> $config_host_mak
-fi
if test "$linux_aio" = "yes" ; then
echo "CONFIG_LINUX_AIO=y" >> $config_host_mak
fi
diff --git a/cpus.c b/cpus.c
index c996ac5..fe18a60 100644
--- a/cpus.c
+++ b/cpus.c
@@ -173,12 +173,9 @@ static void cpu_handle_guest_debug(CPUState *env)
{
gdb_set_stop_cpu(env);
qemu_system_debug_request();
-#ifdef CONFIG_IOTHREAD
env->stopped = 1;
-#endif
}
-#ifdef CONFIG_IOTHREAD
static void cpu_signal(int sig)
{
if (cpu_single_env) {
@@ -186,7 +183,6 @@ static void cpu_signal(int sig)
}
exit_request = 1;
}
-#endif
#ifdef CONFIG_LINUX
static void sigbus_reraise(void)
@@ -262,12 +258,6 @@ static void qemu_kvm_eat_signals(CPUState *env)
exit(1);
}
} while (sigismember(&chkset, SIG_IPI) || sigismember(&chkset, SIGBUS));
-
-#ifndef CONFIG_IOTHREAD
- if (sigismember(&chkset, SIGIO) || sigismember(&chkset, SIGALRM)) {
- qemu_notify_event();
- }
-#endif
}
#else /* !CONFIG_LINUX */
@@ -390,7 +380,6 @@ static int qemu_signal_init(void)
int sigfd;
sigset_t set;
-#ifdef CONFIG_IOTHREAD
/* SIGUSR2 used by posix-aio-compat.c */
sigemptyset(&set);
sigaddset(&set, SIGUSR2);
@@ -409,18 +398,6 @@ static int qemu_signal_init(void)
sigaddset(&set, SIGIO);
sigaddset(&set, SIGALRM);
sigaddset(&set, SIGBUS);
-#else
- sigemptyset(&set);
- sigaddset(&set, SIGBUS);
- if (kvm_enabled()) {
- /*
- * We need to process timer signals synchronously to avoid a race
- * between exit_request check and KVM vcpu entry.
- */
- sigaddset(&set, SIGIO);
- sigaddset(&set, SIGALRM);
- }
-#endif
pthread_sigmask(SIG_BLOCK, &set, NULL);
sigfd = qemu_signalfd(&set);
@@ -447,7 +424,6 @@ static void qemu_kvm_init_cpu_signals(CPUState *env)
sigact.sa_handler = dummy_signal;
sigaction(SIG_IPI, &sigact, NULL);
-#ifdef CONFIG_IOTHREAD
pthread_sigmask(SIG_BLOCK, NULL, &set);
sigdelset(&set, SIG_IPI);
sigdelset(&set, SIGBUS);
@@ -456,17 +432,7 @@ static void qemu_kvm_init_cpu_signals(CPUState *env)
fprintf(stderr, "kvm_set_signal_mask: %s\n", strerror(-r));
exit(1);
}
-#else
- sigemptyset(&set);
- sigaddset(&set, SIG_IPI);
- sigaddset(&set, SIGIO);
- sigaddset(&set, SIGALRM);
- pthread_sigmask(SIG_BLOCK, &set, NULL);
- pthread_sigmask(SIG_BLOCK, NULL, &set);
- sigdelset(&set, SIGIO);
- sigdelset(&set, SIGALRM);
-#endif
sigdelset(&set, SIG_IPI);
sigdelset(&set, SIGBUS);
r = kvm_set_signal_mask(env, &set);
@@ -478,7 +444,6 @@ static void qemu_kvm_init_cpu_signals(CPUState *env)
static void qemu_tcg_init_cpu_signals(void)
{
-#ifdef CONFIG_IOTHREAD
sigset_t set;
struct sigaction sigact;
@@ -489,7 +454,6 @@ static void qemu_tcg_init_cpu_signals(void)
sigemptyset(&set);
sigaddset(&set, SIG_IPI);
pthread_sigmask(SIG_UNBLOCK, &set, NULL);
-#endif
}
#else /* _WIN32 */
@@ -535,106 +499,6 @@ static void qemu_tcg_init_cpu_signals(void)
}
#endif /* _WIN32 */
-#ifndef CONFIG_IOTHREAD
-int qemu_init_main_loop(void)
-{
- int ret;
-
- ret = qemu_signal_init();
- if (ret) {
- return ret;
- }
-
- qemu_init_sigbus();
-
- return qemu_event_init();
-}
-
-void qemu_main_loop_start(void)
-{
-}
-
-void qemu_init_vcpu(void *_env)
-{
- CPUState *env = _env;
- int r;
-
- env->nr_cores = smp_cores;
- env->nr_threads = smp_threads;
-
- if (kvm_enabled()) {
- r = kvm_init_vcpu(env);
- if (r < 0) {
- fprintf(stderr, "kvm_init_vcpu failed: %s\n", strerror(-r));
- exit(1);
- }
- qemu_kvm_init_cpu_signals(env);
- } else {
- qemu_tcg_init_cpu_signals();
- }
-}
-
-int qemu_cpu_is_self(void *env)
-{
- return 1;
-}
-
-void run_on_cpu(CPUState *env, void (*func)(void *data), void *data)
-{
- func(data);
-}
-
-void resume_all_vcpus(void)
-{
-}
-
-void pause_all_vcpus(void)
-{
-}
-
-void qemu_cpu_kick(void *env)
-{
-}
-
-void qemu_cpu_kick_self(void)
-{
-#ifndef _WIN32
- assert(cpu_single_env);
-
- raise(SIG_IPI);
-#else
- abort();
-#endif
-}
-
-void qemu_notify_event(void)
-{
- CPUState *env = cpu_single_env;
-
- qemu_event_increment ();
- if (env) {
- cpu_exit(env);
- }
- if (next_cpu && env != next_cpu) {
- cpu_exit(next_cpu);
- }
- exit_request = 1;
-}
-
-void qemu_mutex_lock_iothread(void) {}
-void qemu_mutex_unlock_iothread(void) {}
-
-void cpu_stop_current(void)
-{
-}
-
-void vm_stop(int reason)
-{
- do_vm_stop(reason);
-}
-
-#else /* CONFIG_IOTHREAD */
-
QemuMutex qemu_global_mutex;
static QemuCond qemu_io_proceeded_cond;
static bool iothread_requesting_mutex;
@@ -1036,8 +900,6 @@ void vm_stop(int reason)
do_vm_stop(reason);
}
-#endif
-
static int tcg_cpu_exec(CPUState *env)
{
int ret;
@@ -1092,11 +954,6 @@ bool cpu_exec_all(void)
qemu_clock_enable(vm_clock,
(env->singlestep_enabled & SSTEP_NOTIMER) == 0);
-#ifndef CONFIG_IOTHREAD
- if (qemu_alarm_pending()) {
- break;
- }
-#endif
if (cpu_can_run(env)) {
if (kvm_enabled()) {
r = kvm_cpu_exec(env);
diff --git a/hw/qxl.c b/hw/qxl.c
index bab60a5..c3a3e97 100644
--- a/hw/qxl.c
+++ b/hw/qxl.c
@@ -1388,11 +1388,7 @@ static void init_pipe_signaling(PCIQXLDevice *d)
dprint(d, 1, "%s: pipe creation failed\n", __FUNCTION__);
return;
}
-#ifdef CONFIG_IOTHREAD
fcntl(d->pipe[0], F_SETFL, O_NONBLOCK);
-#else
- fcntl(d->pipe[0], F_SETFL, O_NONBLOCK /* | O_ASYNC */);
-#endif
fcntl(d->pipe[1], F_SETFL, O_NONBLOCK);
fcntl(d->pipe[0], F_SETOWN, getpid());
diff --git a/kvm-all.c b/kvm-all.c
index 0ae2e26..fbb9ff3 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -479,7 +479,7 @@ static int kvm_check_many_ioeventfds(void)
* Older kernels have a 6 device limit on the KVM io bus. Find out so we
* can avoid creating too many ioeventfds.
*/
-#if defined(CONFIG_EVENTFD) && defined(CONFIG_IOTHREAD)
+#if defined(CONFIG_EVENTFD)
int ioeventfds[7];
int i, ret = 0;
for (i = 0; i < ARRAY_SIZE(ioeventfds); i++) {
diff --git a/qemu-timer.c b/qemu-timer.c
index 19313d3..46dd483 100644
--- a/qemu-timer.c
+++ b/qemu-timer.c
@@ -101,22 +101,6 @@ static int64_t cpu_get_clock(void)
}
}
-#ifndef CONFIG_IOTHREAD
-static int64_t qemu_icount_delta(void)
-{
- if (!use_icount) {
- return 5000 * (int64_t) 1000000;
- } else if (use_icount == 1) {
- /* When not using an adaptive execution frequency
- we tend to get badly out of sync with real time,
- so just delay for a reasonable amount of time. */
- return 0;
- } else {
- return cpu_get_icount() - cpu_get_clock();
- }
-}
-#endif
-
/* enable cpu_get_ticks() */
void cpu_enable_ticks(void)
{
@@ -688,9 +672,7 @@ void configure_icount(const char *option)
if (!option)
return;
-#ifdef CONFIG_IOTHREAD
vm_clock->warp_timer = qemu_new_timer_ns(rt_clock, icount_warp_rt, NULL);
-#endif
if (strcmp(option, "auto") != 0) {
icount_time_shift = strtol(option, NULL, 0);
@@ -1178,41 +1160,6 @@ void quit_timers(void)
int qemu_calculate_timeout(void)
{
-#ifndef CONFIG_IOTHREAD
- int timeout;
-
- if (!vm_running)
- timeout = 5000;
- else {
- /* XXX: use timeout computed from timers */
- int64_t add;
- int64_t delta;
- /* Advance virtual time to the next event. */
- delta = qemu_icount_delta();
- if (delta > 0) {
- /* If virtual time is ahead of real time then just
- wait for IO. */
- timeout = (delta + 999999) / 1000000;
- } else {
- /* Wait for either IO to occur or the next
- timer event. */
- add = qemu_next_icount_deadline();
- /* We advance the timer before checking for IO.
- Limit the amount we advance so that early IO
- activity won't get the guest too far ahead. */
- if (add > 10000000)
- add = 10000000;
- delta += add;
- qemu_icount += qemu_icount_round (add);
- timeout = delta / 1000000;
- if (timeout < 0)
- timeout = 0;
- }
- }
-
- return timeout;
-#else /* CONFIG_IOTHREAD */
return 1000;
-#endif
}
diff --git a/vl.c b/vl.c
index d661e8e..11f5669 100644
--- a/vl.c
+++ b/vl.c
@@ -1438,17 +1438,6 @@ void main_loop_wait(int nonblocking)
}
-#ifndef CONFIG_IOTHREAD
-static int vm_request_pending(void)
-{
- return powerdown_requested ||
- reset_requested ||
- shutdown_requested ||
- debug_requested ||
- vmstop_requested;
-}
-#endif
-
qemu_irq qemu_system_powerdown;
static void main_loop(void)
@@ -1462,12 +1451,6 @@ static void main_loop(void)
qemu_main_loop_start();
for (;;) {
-#ifndef CONFIG_IOTHREAD
- nonblocking = cpu_exec_all();
- if (vm_request_pending()) {
- nonblocking = true;
- }
-#endif
#ifdef CONFIG_PROFILER
ti = profile_getclock();
#endif
--
1.7.4.1
