From 12d4536f7d911b6d87a766ad7300482ea663cea2 Mon Sep 17 00:00:00 2001 From: Anthony Liguori Date: Mon, 22 Aug 2011 08:24:58 -0500 Subject: [PATCH] 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 --- configure | 13 ----- cpus.c | 143 --------------------------------------------------- hw/qxl.c | 4 -- kvm-all.c | 2 +- qemu-timer.c | 53 ------------------- vl.c | 18 ------- 6 files changed, 1 insertion(+), 232 deletions(-) diff --git a/configure b/configure index 1fb31c79a8..eba6fc611b 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" @@ -723,8 +722,6 @@ for opt do ;; --enable-attr) attr="yes" ;; - --enable-io-thread) io_thread="yes" - ;; --disable-blobs) blobs="no" ;; --with-pkgversion=*) pkgversion=" ($optarg)" @@ -2158,12 +2155,6 @@ EOF if compile_prog "" "" ; then signalfd=yes -elif test "$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 @@ -2710,7 +2701,6 @@ 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 $blobs" @@ -2968,9 +2958,6 @@ if test "$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 b163efe4a8..54c188cf5c 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; @@ -1028,8 +892,6 @@ void vm_stop(int reason) do_vm_stop(reason); } -#endif - static int tcg_cpu_exec(CPUState *env) { int ret; @@ -1084,11 +946,6 @@ 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 1d9077db68..45e24016fc 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 0ae2e2697e..fbb9ff3bef 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 19313d3b00..46dd483fdd 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 60bce0cc71..7a6fbacee5 100644 --- a/vl.c +++ b/vl.c @@ -1445,17 +1445,6 @@ int main_loop_wait(int nonblocking) return ret; } -#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) @@ -1470,14 +1459,7 @@ static void main_loop(void) qemu_main_loop_start(); for (;;) { -#ifdef CONFIG_IOTHREAD nonblocking = !kvm_enabled() && last_io > 0; -#else - nonblocking = cpu_exec_all(); - if (vm_request_pending()) { - nonblocking = true; - } -#endif #ifdef CONFIG_PROFILER ti = profile_getclock(); #endif