mirror of
https://github.com/qemu/qemu.git
synced 2024-11-27 05:43:47 +08:00
main: force enabling of I/O thread
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 <aliguori@us.ibm.com>
This commit is contained in:
Anthony Liguori
parent
d9cd446b4f
commit
12d4536f7d
13
configure
vendored
13
configure
vendored
@ -165,7 +165,6 @@ darwin_user="no"
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bsd_user="no"
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guest_base=""
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uname_release=""
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io_thread="no"
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mixemu="no"
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aix="no"
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blobs="yes"
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@ -723,8 +722,6 @@ for opt do
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;;
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--enable-attr) attr="yes"
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;;
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--enable-io-thread) io_thread="yes"
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;;
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--disable-blobs) blobs="no"
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;;
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--with-pkgversion=*) pkgversion=" ($optarg)"
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@ -2158,12 +2155,6 @@ EOF
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if compile_prog "" "" ; then
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signalfd=yes
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elif test "$kvm" = "yes" -a "$io_thread" != "yes"; then
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echo
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echo "ERROR: Host kernel lacks signalfd() support,"
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echo "but KVM depends on it when the IO thread is disabled."
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echo
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exit 1
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fi
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# check if eventfd is supported
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@ -2710,7 +2701,6 @@ echo "NPTL support $nptl"
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echo "GUEST_BASE $guest_base"
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echo "PIE user targets $user_pie"
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echo "vde support $vde"
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echo "IO thread $io_thread"
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echo "Linux AIO support $linux_aio"
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echo "ATTR/XATTR support $attr"
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echo "Install blobs $blobs"
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@ -2968,9 +2958,6 @@ if test "$xen" = "yes" ; then
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echo "CONFIG_XEN_BACKEND=y" >> $config_host_mak
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echo "CONFIG_XEN_CTRL_INTERFACE_VERSION=$xen_ctrl_version" >> $config_host_mak
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fi
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if test "$io_thread" = "yes" ; then
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echo "CONFIG_IOTHREAD=y" >> $config_host_mak
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fi
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if test "$linux_aio" = "yes" ; then
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echo "CONFIG_LINUX_AIO=y" >> $config_host_mak
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fi
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143
cpus.c
143
cpus.c
@ -173,12 +173,9 @@ static void cpu_handle_guest_debug(CPUState *env)
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{
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gdb_set_stop_cpu(env);
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qemu_system_debug_request();
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#ifdef CONFIG_IOTHREAD
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env->stopped = 1;
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#endif
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}
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#ifdef CONFIG_IOTHREAD
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static void cpu_signal(int sig)
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{
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if (cpu_single_env) {
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@ -186,7 +183,6 @@ static void cpu_signal(int sig)
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}
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exit_request = 1;
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}
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#endif
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#ifdef CONFIG_LINUX
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static void sigbus_reraise(void)
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@ -262,12 +258,6 @@ static void qemu_kvm_eat_signals(CPUState *env)
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exit(1);
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}
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} while (sigismember(&chkset, SIG_IPI) || sigismember(&chkset, SIGBUS));
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#ifndef CONFIG_IOTHREAD
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if (sigismember(&chkset, SIGIO) || sigismember(&chkset, SIGALRM)) {
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qemu_notify_event();
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}
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#endif
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}
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#else /* !CONFIG_LINUX */
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@ -390,7 +380,6 @@ static int qemu_signal_init(void)
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int sigfd;
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sigset_t set;
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#ifdef CONFIG_IOTHREAD
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/* SIGUSR2 used by posix-aio-compat.c */
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sigemptyset(&set);
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sigaddset(&set, SIGUSR2);
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@ -409,18 +398,6 @@ static int qemu_signal_init(void)
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sigaddset(&set, SIGIO);
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sigaddset(&set, SIGALRM);
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sigaddset(&set, SIGBUS);
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#else
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sigemptyset(&set);
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sigaddset(&set, SIGBUS);
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if (kvm_enabled()) {
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/*
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* We need to process timer signals synchronously to avoid a race
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* between exit_request check and KVM vcpu entry.
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*/
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sigaddset(&set, SIGIO);
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sigaddset(&set, SIGALRM);
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}
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#endif
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pthread_sigmask(SIG_BLOCK, &set, NULL);
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sigfd = qemu_signalfd(&set);
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@ -447,7 +424,6 @@ static void qemu_kvm_init_cpu_signals(CPUState *env)
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sigact.sa_handler = dummy_signal;
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sigaction(SIG_IPI, &sigact, NULL);
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#ifdef CONFIG_IOTHREAD
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pthread_sigmask(SIG_BLOCK, NULL, &set);
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sigdelset(&set, SIG_IPI);
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sigdelset(&set, SIGBUS);
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@ -456,17 +432,7 @@ static void qemu_kvm_init_cpu_signals(CPUState *env)
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fprintf(stderr, "kvm_set_signal_mask: %s\n", strerror(-r));
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exit(1);
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}
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#else
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sigemptyset(&set);
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sigaddset(&set, SIG_IPI);
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sigaddset(&set, SIGIO);
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sigaddset(&set, SIGALRM);
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pthread_sigmask(SIG_BLOCK, &set, NULL);
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pthread_sigmask(SIG_BLOCK, NULL, &set);
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sigdelset(&set, SIGIO);
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sigdelset(&set, SIGALRM);
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#endif
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sigdelset(&set, SIG_IPI);
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sigdelset(&set, SIGBUS);
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r = kvm_set_signal_mask(env, &set);
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@ -478,7 +444,6 @@ static void qemu_kvm_init_cpu_signals(CPUState *env)
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static void qemu_tcg_init_cpu_signals(void)
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{
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#ifdef CONFIG_IOTHREAD
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sigset_t set;
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struct sigaction sigact;
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@ -489,7 +454,6 @@ static void qemu_tcg_init_cpu_signals(void)
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sigemptyset(&set);
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sigaddset(&set, SIG_IPI);
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pthread_sigmask(SIG_UNBLOCK, &set, NULL);
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#endif
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}
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#else /* _WIN32 */
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@ -535,106 +499,6 @@ static void qemu_tcg_init_cpu_signals(void)
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}
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#endif /* _WIN32 */
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#ifndef CONFIG_IOTHREAD
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int qemu_init_main_loop(void)
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{
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int ret;
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ret = qemu_signal_init();
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if (ret) {
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return ret;
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}
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qemu_init_sigbus();
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return qemu_event_init();
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}
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void qemu_main_loop_start(void)
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{
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}
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void qemu_init_vcpu(void *_env)
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{
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CPUState *env = _env;
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int r;
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env->nr_cores = smp_cores;
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env->nr_threads = smp_threads;
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if (kvm_enabled()) {
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r = kvm_init_vcpu(env);
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if (r < 0) {
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fprintf(stderr, "kvm_init_vcpu failed: %s\n", strerror(-r));
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exit(1);
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}
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qemu_kvm_init_cpu_signals(env);
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} else {
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qemu_tcg_init_cpu_signals();
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}
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}
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int qemu_cpu_is_self(void *env)
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{
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return 1;
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}
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void run_on_cpu(CPUState *env, void (*func)(void *data), void *data)
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{
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func(data);
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}
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void resume_all_vcpus(void)
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{
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}
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void pause_all_vcpus(void)
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{
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}
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void qemu_cpu_kick(void *env)
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{
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}
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void qemu_cpu_kick_self(void)
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{
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#ifndef _WIN32
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assert(cpu_single_env);
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raise(SIG_IPI);
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#else
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abort();
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#endif
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}
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void qemu_notify_event(void)
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{
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CPUState *env = cpu_single_env;
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qemu_event_increment ();
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if (env) {
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cpu_exit(env);
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}
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if (next_cpu && env != next_cpu) {
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cpu_exit(next_cpu);
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}
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exit_request = 1;
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}
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void qemu_mutex_lock_iothread(void) {}
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void qemu_mutex_unlock_iothread(void) {}
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void cpu_stop_current(void)
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{
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}
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void vm_stop(int reason)
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{
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do_vm_stop(reason);
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}
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#else /* CONFIG_IOTHREAD */
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QemuMutex qemu_global_mutex;
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static QemuCond qemu_io_proceeded_cond;
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static bool iothread_requesting_mutex;
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@ -1028,8 +892,6 @@ void vm_stop(int reason)
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do_vm_stop(reason);
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}
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#endif
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static int tcg_cpu_exec(CPUState *env)
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{
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int ret;
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@ -1084,11 +946,6 @@ bool cpu_exec_all(void)
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qemu_clock_enable(vm_clock,
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(env->singlestep_enabled & SSTEP_NOTIMER) == 0);
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#ifndef CONFIG_IOTHREAD
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if (qemu_alarm_pending()) {
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break;
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}
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#endif
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if (cpu_can_run(env)) {
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if (kvm_enabled()) {
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r = kvm_cpu_exec(env);
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4
hw/qxl.c
4
hw/qxl.c
@ -1388,11 +1388,7 @@ static void init_pipe_signaling(PCIQXLDevice *d)
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dprint(d, 1, "%s: pipe creation failed\n", __FUNCTION__);
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return;
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}
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#ifdef CONFIG_IOTHREAD
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fcntl(d->pipe[0], F_SETFL, O_NONBLOCK);
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#else
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fcntl(d->pipe[0], F_SETFL, O_NONBLOCK /* | O_ASYNC */);
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#endif
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fcntl(d->pipe[1], F_SETFL, O_NONBLOCK);
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fcntl(d->pipe[0], F_SETOWN, getpid());
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@ -479,7 +479,7 @@ static int kvm_check_many_ioeventfds(void)
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* Older kernels have a 6 device limit on the KVM io bus. Find out so we
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* can avoid creating too many ioeventfds.
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*/
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#if defined(CONFIG_EVENTFD) && defined(CONFIG_IOTHREAD)
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#if defined(CONFIG_EVENTFD)
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int ioeventfds[7];
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int i, ret = 0;
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for (i = 0; i < ARRAY_SIZE(ioeventfds); i++) {
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53
qemu-timer.c
53
qemu-timer.c
@ -101,22 +101,6 @@ static int64_t cpu_get_clock(void)
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}
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}
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#ifndef CONFIG_IOTHREAD
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static int64_t qemu_icount_delta(void)
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{
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if (!use_icount) {
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return 5000 * (int64_t) 1000000;
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} else if (use_icount == 1) {
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/* When not using an adaptive execution frequency
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we tend to get badly out of sync with real time,
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so just delay for a reasonable amount of time. */
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return 0;
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} else {
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return cpu_get_icount() - cpu_get_clock();
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}
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}
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#endif
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/* enable cpu_get_ticks() */
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void cpu_enable_ticks(void)
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{
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@ -688,9 +672,7 @@ void configure_icount(const char *option)
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if (!option)
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return;
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#ifdef CONFIG_IOTHREAD
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vm_clock->warp_timer = qemu_new_timer_ns(rt_clock, icount_warp_rt, NULL);
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#endif
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if (strcmp(option, "auto") != 0) {
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icount_time_shift = strtol(option, NULL, 0);
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@ -1178,41 +1160,6 @@ void quit_timers(void)
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int qemu_calculate_timeout(void)
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{
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#ifndef CONFIG_IOTHREAD
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int timeout;
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if (!vm_running)
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timeout = 5000;
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else {
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/* XXX: use timeout computed from timers */
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int64_t add;
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int64_t delta;
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/* Advance virtual time to the next event. */
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delta = qemu_icount_delta();
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if (delta > 0) {
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/* If virtual time is ahead of real time then just
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wait for IO. */
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timeout = (delta + 999999) / 1000000;
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} else {
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/* Wait for either IO to occur or the next
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timer event. */
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add = qemu_next_icount_deadline();
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/* We advance the timer before checking for IO.
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Limit the amount we advance so that early IO
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activity won't get the guest too far ahead. */
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if (add > 10000000)
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add = 10000000;
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delta += add;
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qemu_icount += qemu_icount_round (add);
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timeout = delta / 1000000;
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if (timeout < 0)
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timeout = 0;
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}
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}
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return timeout;
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#else /* CONFIG_IOTHREAD */
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return 1000;
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#endif
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}
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18
vl.c
18
vl.c
@ -1445,17 +1445,6 @@ int main_loop_wait(int nonblocking)
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return ret;
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}
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#ifndef CONFIG_IOTHREAD
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static int vm_request_pending(void)
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{
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return powerdown_requested ||
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reset_requested ||
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shutdown_requested ||
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debug_requested ||
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vmstop_requested;
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}
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#endif
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qemu_irq qemu_system_powerdown;
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static void main_loop(void)
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@ -1470,14 +1459,7 @@ static void main_loop(void)
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qemu_main_loop_start();
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for (;;) {
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#ifdef CONFIG_IOTHREAD
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nonblocking = !kvm_enabled() && last_io > 0;
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#else
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nonblocking = cpu_exec_all();
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if (vm_request_pending()) {
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nonblocking = true;
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}
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#endif
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#ifdef CONFIG_PROFILER
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ti = profile_getclock();
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#endif
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Block a user