qemu-e2k/util/vhost-user-server.c

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/*
* Sharing QEMU devices via vhost-user protocol
*
* Copyright (c) Coiby Xu <coiby.xu@gmail.com>.
* Copyright (c) 2020 Red Hat, Inc.
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* later. See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qemu/main-loop.h"
#include "qemu/vhost-user-server.h"
#include "block/aio-wait.h"
/*
* Theory of operation:
*
* VuServer is started and stopped by vhost_user_server_start() and
* vhost_user_server_stop() from the main loop thread. Starting the server
* opens a vhost-user UNIX domain socket and listens for incoming connections.
* Only one connection is allowed at a time.
*
* The connection is handled by the vu_client_trip() coroutine in the
* VuServer->ctx AioContext. The coroutine consists of a vu_dispatch() loop
* where libvhost-user calls vu_message_read() to receive the next vhost-user
* protocol messages over the UNIX domain socket.
*
* When virtqueues are set up libvhost-user calls set_watch() to monitor kick
* fds. These fds are also handled in the VuServer->ctx AioContext.
*
* Both vu_client_trip() and kick fd monitoring can be stopped by shutting down
* the socket connection. Shutting down the socket connection causes
* vu_message_read() to fail since no more data can be received from the socket.
* After vu_dispatch() fails, vu_client_trip() calls vu_deinit() to stop
* libvhost-user before terminating the coroutine. vu_deinit() calls
* remove_watch() to stop monitoring kick fds and this stops virtqueue
* processing.
*
* When vu_client_trip() has finished cleaning up it schedules a BH in the main
* loop thread to accept the next client connection.
*
* When libvhost-user detects an error it calls panic_cb() and sets the
* dev->broken flag. Both vu_client_trip() and kick fd processing stop when
* the dev->broken flag is set.
*
* It is possible to switch AioContexts using
* vhost_user_server_detach_aio_context() and
* vhost_user_server_attach_aio_context(). They stop monitoring fds in the old
* AioContext and resume monitoring in the new AioContext. The vu_client_trip()
* coroutine remains in a yielded state during the switch. This is made
* possible by QIOChannel's support for spurious coroutine re-entry in
* qio_channel_yield(). The coroutine will restart I/O when re-entered from the
* new AioContext.
*/
static void vmsg_close_fds(VhostUserMsg *vmsg)
{
int i;
for (i = 0; i < vmsg->fd_num; i++) {
close(vmsg->fds[i]);
}
}
static void vmsg_unblock_fds(VhostUserMsg *vmsg)
{
int i;
for (i = 0; i < vmsg->fd_num; i++) {
qemu_socket_set_nonblock(vmsg->fds[i]);
}
}
static void panic_cb(VuDev *vu_dev, const char *buf)
{
error_report("vu_panic: %s", buf);
}
void vhost_user_server_ref(VuServer *server)
{
assert(!server->wait_idle);
server->refcount++;
}
void vhost_user_server_unref(VuServer *server)
{
server->refcount--;
if (server->wait_idle && !server->refcount) {
aio_co_wake(server->co_trip);
}
}
static bool coroutine_fn
vu_message_read(VuDev *vu_dev, int conn_fd, VhostUserMsg *vmsg)
{
struct iovec iov = {
.iov_base = (char *)vmsg,
.iov_len = VHOST_USER_HDR_SIZE,
};
int rc, read_bytes = 0;
Error *local_err = NULL;
const size_t max_fds = G_N_ELEMENTS(vmsg->fds);
VuServer *server = container_of(vu_dev, VuServer, vu_dev);
QIOChannel *ioc = server->ioc;
vmsg->fd_num = 0;
if (!ioc) {
error_report_err(local_err);
goto fail;
}
assert(qemu_in_coroutine());
do {
size_t nfds = 0;
int *fds = NULL;
/*
* qio_channel_readv_full may have short reads, keeping calling it
* until getting VHOST_USER_HDR_SIZE or 0 bytes in total
*/
rc = qio_channel_readv_full(ioc, &iov, 1, &fds, &nfds, &local_err);
if (rc < 0) {
if (rc == QIO_CHANNEL_ERR_BLOCK) {
assert(local_err == NULL);
qio_channel_yield(ioc, G_IO_IN);
continue;
} else {
error_report_err(local_err);
goto fail;
}
}
if (nfds > 0) {
if (vmsg->fd_num + nfds > max_fds) {
error_report("A maximum of %zu fds are allowed, "
"however got %zu fds now",
max_fds, vmsg->fd_num + nfds);
g_free(fds);
goto fail;
}
memcpy(vmsg->fds + vmsg->fd_num, fds, nfds * sizeof(vmsg->fds[0]));
vmsg->fd_num += nfds;
g_free(fds);
}
if (rc == 0) { /* socket closed */
goto fail;
}
iov.iov_base += rc;
iov.iov_len -= rc;
read_bytes += rc;
} while (read_bytes != VHOST_USER_HDR_SIZE);
/* qio_channel_readv_full will make socket fds blocking, unblock them */
vmsg_unblock_fds(vmsg);
if (vmsg->size > sizeof(vmsg->payload)) {
error_report("Error: too big message request: %d, "
"size: vmsg->size: %u, "
"while sizeof(vmsg->payload) = %zu",
vmsg->request, vmsg->size, sizeof(vmsg->payload));
goto fail;
}
struct iovec iov_payload = {
.iov_base = (char *)&vmsg->payload,
.iov_len = vmsg->size,
};
if (vmsg->size) {
rc = qio_channel_readv_all_eof(ioc, &iov_payload, 1, &local_err);
if (rc != 1) {
if (local_err) {
error_report_err(local_err);
}
goto fail;
}
}
return true;
fail:
vmsg_close_fds(vmsg);
return false;
}
static coroutine_fn void vu_client_trip(void *opaque)
{
VuServer *server = opaque;
VuDev *vu_dev = &server->vu_dev;
while (!vu_dev->broken && vu_dispatch(vu_dev)) {
/* Keep running */
}
if (server->refcount) {
/* Wait for requests to complete before we can unmap the memory */
server->wait_idle = true;
qemu_coroutine_yield();
server->wait_idle = false;
}
assert(server->refcount == 0);
vu_deinit(vu_dev);
/* vu_deinit() should have called remove_watch() */
assert(QTAILQ_EMPTY(&server->vu_fd_watches));
object_unref(OBJECT(server->sioc));
server->sioc = NULL;
object_unref(OBJECT(server->ioc));
server->ioc = NULL;
server->co_trip = NULL;
if (server->restart_listener_bh) {
qemu_bh_schedule(server->restart_listener_bh);
}
aio_wait_kick();
}
/*
* a wrapper for vu_kick_cb
*
* since aio_dispatch can only pass one user data pointer to the
* callback function, pack VuDev and pvt into a struct. Then unpack it
* and pass them to vu_kick_cb
*/
static void kick_handler(void *opaque)
{
VuFdWatch *vu_fd_watch = opaque;
VuDev *vu_dev = vu_fd_watch->vu_dev;
vu_fd_watch->cb(vu_dev, 0, vu_fd_watch->pvt);
/* Stop vu_client_trip() if an error occurred in vu_fd_watch->cb() */
if (vu_dev->broken) {
VuServer *server = container_of(vu_dev, VuServer, vu_dev);
qio_channel_shutdown(server->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
}
}
static VuFdWatch *find_vu_fd_watch(VuServer *server, int fd)
{
VuFdWatch *vu_fd_watch, *next;
QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) {
if (vu_fd_watch->fd == fd) {
return vu_fd_watch;
}
}
return NULL;
}
static void
set_watch(VuDev *vu_dev, int fd, int vu_evt,
vu_watch_cb cb, void *pvt)
{
VuServer *server = container_of(vu_dev, VuServer, vu_dev);
g_assert(vu_dev);
g_assert(fd >= 0);
g_assert(cb);
VuFdWatch *vu_fd_watch = find_vu_fd_watch(server, fd);
if (!vu_fd_watch) {
VuFdWatch *vu_fd_watch = g_new0(VuFdWatch, 1);
QTAILQ_INSERT_TAIL(&server->vu_fd_watches, vu_fd_watch, next);
vu_fd_watch->fd = fd;
vu_fd_watch->cb = cb;
qemu_socket_set_nonblock(fd);
aio_set_fd_handler(server->ioc->ctx, fd, true, kick_handler,
aio-posix: split poll check from ready handler Adaptive polling measures the execution time of the polling check plus handlers called when a polled event becomes ready. Handlers can take a significant amount of time, making it look like polling was running for a long time when in fact the event handler was running for a long time. For example, on Linux the io_submit(2) syscall invoked when a virtio-blk device's virtqueue becomes ready can take 10s of microseconds. This can exceed the default polling interval (32 microseconds) and cause adaptive polling to stop polling. By excluding the handler's execution time from the polling check we make the adaptive polling calculation more accurate. As a result, the event loop now stays in polling mode where previously it would have fallen back to file descriptor monitoring. The following data was collected with virtio-blk num-queues=2 event_idx=off using an IOThread. Before: 168k IOPS, IOThread syscalls: 9837.115 ( 0.020 ms): IO iothread1/620155 io_submit(ctx_id: 140512552468480, nr: 16, iocbpp: 0x7fcb9f937db0) = 16 9837.158 ( 0.002 ms): IO iothread1/620155 write(fd: 103, buf: 0x556a2ef71b88, count: 8) = 8 9837.161 ( 0.001 ms): IO iothread1/620155 write(fd: 104, buf: 0x556a2ef71b88, count: 8) = 8 9837.163 ( 0.001 ms): IO iothread1/620155 ppoll(ufds: 0x7fcb90002800, nfds: 4, tsp: 0x7fcb9f1342d0, sigsetsize: 8) = 3 9837.164 ( 0.001 ms): IO iothread1/620155 read(fd: 107, buf: 0x7fcb9f939cc0, count: 512) = 8 9837.174 ( 0.001 ms): IO iothread1/620155 read(fd: 105, buf: 0x7fcb9f939cc0, count: 512) = 8 9837.176 ( 0.001 ms): IO iothread1/620155 read(fd: 106, buf: 0x7fcb9f939cc0, count: 512) = 8 9837.209 ( 0.035 ms): IO iothread1/620155 io_submit(ctx_id: 140512552468480, nr: 32, iocbpp: 0x7fca7d0cebe0) = 32 174k IOPS (+3.6%), IOThread syscalls: 9809.566 ( 0.036 ms): IO iothread1/623061 io_submit(ctx_id: 140539805028352, nr: 32, iocbpp: 0x7fd0cdd62be0) = 32 9809.625 ( 0.001 ms): IO iothread1/623061 write(fd: 103, buf: 0x5647cfba5f58, count: 8) = 8 9809.627 ( 0.002 ms): IO iothread1/623061 write(fd: 104, buf: 0x5647cfba5f58, count: 8) = 8 9809.663 ( 0.036 ms): IO iothread1/623061 io_submit(ctx_id: 140539805028352, nr: 32, iocbpp: 0x7fd0d0388b50) = 32 Notice that ppoll(2) and eventfd read(2) syscalls are eliminated because the IOThread stays in polling mode instead of falling back to file descriptor monitoring. As usual, polling is not implemented on Windows so this patch ignores the new io_poll_read() callback in aio-win32.c. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20211207132336.36627-2-stefanha@redhat.com [Fixed up aio_set_event_notifier() calls in tests/unit/test-fdmon-epoll.c added after this series was queued. --Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2021-12-07 14:23:31 +01:00
NULL, NULL, NULL, vu_fd_watch);
vu_fd_watch->vu_dev = vu_dev;
vu_fd_watch->pvt = pvt;
}
}
static void remove_watch(VuDev *vu_dev, int fd)
{
VuServer *server;
g_assert(vu_dev);
g_assert(fd >= 0);
server = container_of(vu_dev, VuServer, vu_dev);
VuFdWatch *vu_fd_watch = find_vu_fd_watch(server, fd);
if (!vu_fd_watch) {
return;
}
aio-posix: split poll check from ready handler Adaptive polling measures the execution time of the polling check plus handlers called when a polled event becomes ready. Handlers can take a significant amount of time, making it look like polling was running for a long time when in fact the event handler was running for a long time. For example, on Linux the io_submit(2) syscall invoked when a virtio-blk device's virtqueue becomes ready can take 10s of microseconds. This can exceed the default polling interval (32 microseconds) and cause adaptive polling to stop polling. By excluding the handler's execution time from the polling check we make the adaptive polling calculation more accurate. As a result, the event loop now stays in polling mode where previously it would have fallen back to file descriptor monitoring. The following data was collected with virtio-blk num-queues=2 event_idx=off using an IOThread. Before: 168k IOPS, IOThread syscalls: 9837.115 ( 0.020 ms): IO iothread1/620155 io_submit(ctx_id: 140512552468480, nr: 16, iocbpp: 0x7fcb9f937db0) = 16 9837.158 ( 0.002 ms): IO iothread1/620155 write(fd: 103, buf: 0x556a2ef71b88, count: 8) = 8 9837.161 ( 0.001 ms): IO iothread1/620155 write(fd: 104, buf: 0x556a2ef71b88, count: 8) = 8 9837.163 ( 0.001 ms): IO iothread1/620155 ppoll(ufds: 0x7fcb90002800, nfds: 4, tsp: 0x7fcb9f1342d0, sigsetsize: 8) = 3 9837.164 ( 0.001 ms): IO iothread1/620155 read(fd: 107, buf: 0x7fcb9f939cc0, count: 512) = 8 9837.174 ( 0.001 ms): IO iothread1/620155 read(fd: 105, buf: 0x7fcb9f939cc0, count: 512) = 8 9837.176 ( 0.001 ms): IO iothread1/620155 read(fd: 106, buf: 0x7fcb9f939cc0, count: 512) = 8 9837.209 ( 0.035 ms): IO iothread1/620155 io_submit(ctx_id: 140512552468480, nr: 32, iocbpp: 0x7fca7d0cebe0) = 32 174k IOPS (+3.6%), IOThread syscalls: 9809.566 ( 0.036 ms): IO iothread1/623061 io_submit(ctx_id: 140539805028352, nr: 32, iocbpp: 0x7fd0cdd62be0) = 32 9809.625 ( 0.001 ms): IO iothread1/623061 write(fd: 103, buf: 0x5647cfba5f58, count: 8) = 8 9809.627 ( 0.002 ms): IO iothread1/623061 write(fd: 104, buf: 0x5647cfba5f58, count: 8) = 8 9809.663 ( 0.036 ms): IO iothread1/623061 io_submit(ctx_id: 140539805028352, nr: 32, iocbpp: 0x7fd0d0388b50) = 32 Notice that ppoll(2) and eventfd read(2) syscalls are eliminated because the IOThread stays in polling mode instead of falling back to file descriptor monitoring. As usual, polling is not implemented on Windows so this patch ignores the new io_poll_read() callback in aio-win32.c. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20211207132336.36627-2-stefanha@redhat.com [Fixed up aio_set_event_notifier() calls in tests/unit/test-fdmon-epoll.c added after this series was queued. --Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2021-12-07 14:23:31 +01:00
aio_set_fd_handler(server->ioc->ctx, fd, true,
NULL, NULL, NULL, NULL, NULL);
QTAILQ_REMOVE(&server->vu_fd_watches, vu_fd_watch, next);
g_free(vu_fd_watch);
}
static void vu_accept(QIONetListener *listener, QIOChannelSocket *sioc,
gpointer opaque)
{
VuServer *server = opaque;
if (server->sioc) {
warn_report("Only one vhost-user client is allowed to "
"connect the server one time");
return;
}
if (!vu_init(&server->vu_dev, server->max_queues, sioc->fd, panic_cb,
vu_message_read, set_watch, remove_watch, server->vu_iface)) {
error_report("Failed to initialize libvhost-user");
return;
}
/*
* Unset the callback function for network listener to make another
* vhost-user client keeping waiting until this client disconnects
*/
qio_net_listener_set_client_func(server->listener,
NULL,
NULL,
NULL);
server->sioc = sioc;
/*
* Increase the object reference, so sioc will not freed by
* qio_net_listener_channel_func which will call object_unref(OBJECT(sioc))
*/
object_ref(OBJECT(server->sioc));
qio_channel_set_name(QIO_CHANNEL(sioc), "vhost-user client");
server->ioc = QIO_CHANNEL(sioc);
object_ref(OBJECT(server->ioc));
/* TODO vu_message_write() spins if non-blocking! */
qio_channel_set_blocking(server->ioc, false, NULL);
server->co_trip = qemu_coroutine_create(vu_client_trip, server);
aio_context_acquire(server->ctx);
vhost_user_server_attach_aio_context(server, server->ctx);
aio_context_release(server->ctx);
}
void vhost_user_server_stop(VuServer *server)
{
aio_context_acquire(server->ctx);
qemu_bh_delete(server->restart_listener_bh);
server->restart_listener_bh = NULL;
if (server->sioc) {
VuFdWatch *vu_fd_watch;
QTAILQ_FOREACH(vu_fd_watch, &server->vu_fd_watches, next) {
aio_set_fd_handler(server->ctx, vu_fd_watch->fd, true,
aio-posix: split poll check from ready handler Adaptive polling measures the execution time of the polling check plus handlers called when a polled event becomes ready. Handlers can take a significant amount of time, making it look like polling was running for a long time when in fact the event handler was running for a long time. For example, on Linux the io_submit(2) syscall invoked when a virtio-blk device's virtqueue becomes ready can take 10s of microseconds. This can exceed the default polling interval (32 microseconds) and cause adaptive polling to stop polling. By excluding the handler's execution time from the polling check we make the adaptive polling calculation more accurate. As a result, the event loop now stays in polling mode where previously it would have fallen back to file descriptor monitoring. The following data was collected with virtio-blk num-queues=2 event_idx=off using an IOThread. Before: 168k IOPS, IOThread syscalls: 9837.115 ( 0.020 ms): IO iothread1/620155 io_submit(ctx_id: 140512552468480, nr: 16, iocbpp: 0x7fcb9f937db0) = 16 9837.158 ( 0.002 ms): IO iothread1/620155 write(fd: 103, buf: 0x556a2ef71b88, count: 8) = 8 9837.161 ( 0.001 ms): IO iothread1/620155 write(fd: 104, buf: 0x556a2ef71b88, count: 8) = 8 9837.163 ( 0.001 ms): IO iothread1/620155 ppoll(ufds: 0x7fcb90002800, nfds: 4, tsp: 0x7fcb9f1342d0, sigsetsize: 8) = 3 9837.164 ( 0.001 ms): IO iothread1/620155 read(fd: 107, buf: 0x7fcb9f939cc0, count: 512) = 8 9837.174 ( 0.001 ms): IO iothread1/620155 read(fd: 105, buf: 0x7fcb9f939cc0, count: 512) = 8 9837.176 ( 0.001 ms): IO iothread1/620155 read(fd: 106, buf: 0x7fcb9f939cc0, count: 512) = 8 9837.209 ( 0.035 ms): IO iothread1/620155 io_submit(ctx_id: 140512552468480, nr: 32, iocbpp: 0x7fca7d0cebe0) = 32 174k IOPS (+3.6%), IOThread syscalls: 9809.566 ( 0.036 ms): IO iothread1/623061 io_submit(ctx_id: 140539805028352, nr: 32, iocbpp: 0x7fd0cdd62be0) = 32 9809.625 ( 0.001 ms): IO iothread1/623061 write(fd: 103, buf: 0x5647cfba5f58, count: 8) = 8 9809.627 ( 0.002 ms): IO iothread1/623061 write(fd: 104, buf: 0x5647cfba5f58, count: 8) = 8 9809.663 ( 0.036 ms): IO iothread1/623061 io_submit(ctx_id: 140539805028352, nr: 32, iocbpp: 0x7fd0d0388b50) = 32 Notice that ppoll(2) and eventfd read(2) syscalls are eliminated because the IOThread stays in polling mode instead of falling back to file descriptor monitoring. As usual, polling is not implemented on Windows so this patch ignores the new io_poll_read() callback in aio-win32.c. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20211207132336.36627-2-stefanha@redhat.com [Fixed up aio_set_event_notifier() calls in tests/unit/test-fdmon-epoll.c added after this series was queued. --Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2021-12-07 14:23:31 +01:00
NULL, NULL, NULL, NULL, vu_fd_watch);
}
qio_channel_shutdown(server->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
AIO_WAIT_WHILE(server->ctx, server->co_trip);
}
aio_context_release(server->ctx);
if (server->listener) {
qio_net_listener_disconnect(server->listener);
object_unref(OBJECT(server->listener));
}
}
/*
* Allow the next client to connect to the server. Called from a BH in the main
* loop.
*/
static void restart_listener_bh(void *opaque)
{
VuServer *server = opaque;
qio_net_listener_set_client_func(server->listener, vu_accept, server,
NULL);
}
/* Called with ctx acquired */
void vhost_user_server_attach_aio_context(VuServer *server, AioContext *ctx)
{
VuFdWatch *vu_fd_watch;
server->ctx = ctx;
if (!server->sioc) {
return;
}
qio_channel_attach_aio_context(server->ioc, ctx);
QTAILQ_FOREACH(vu_fd_watch, &server->vu_fd_watches, next) {
aio_set_fd_handler(ctx, vu_fd_watch->fd, true, kick_handler, NULL,
aio-posix: split poll check from ready handler Adaptive polling measures the execution time of the polling check plus handlers called when a polled event becomes ready. Handlers can take a significant amount of time, making it look like polling was running for a long time when in fact the event handler was running for a long time. For example, on Linux the io_submit(2) syscall invoked when a virtio-blk device's virtqueue becomes ready can take 10s of microseconds. This can exceed the default polling interval (32 microseconds) and cause adaptive polling to stop polling. By excluding the handler's execution time from the polling check we make the adaptive polling calculation more accurate. As a result, the event loop now stays in polling mode where previously it would have fallen back to file descriptor monitoring. The following data was collected with virtio-blk num-queues=2 event_idx=off using an IOThread. Before: 168k IOPS, IOThread syscalls: 9837.115 ( 0.020 ms): IO iothread1/620155 io_submit(ctx_id: 140512552468480, nr: 16, iocbpp: 0x7fcb9f937db0) = 16 9837.158 ( 0.002 ms): IO iothread1/620155 write(fd: 103, buf: 0x556a2ef71b88, count: 8) = 8 9837.161 ( 0.001 ms): IO iothread1/620155 write(fd: 104, buf: 0x556a2ef71b88, count: 8) = 8 9837.163 ( 0.001 ms): IO iothread1/620155 ppoll(ufds: 0x7fcb90002800, nfds: 4, tsp: 0x7fcb9f1342d0, sigsetsize: 8) = 3 9837.164 ( 0.001 ms): IO iothread1/620155 read(fd: 107, buf: 0x7fcb9f939cc0, count: 512) = 8 9837.174 ( 0.001 ms): IO iothread1/620155 read(fd: 105, buf: 0x7fcb9f939cc0, count: 512) = 8 9837.176 ( 0.001 ms): IO iothread1/620155 read(fd: 106, buf: 0x7fcb9f939cc0, count: 512) = 8 9837.209 ( 0.035 ms): IO iothread1/620155 io_submit(ctx_id: 140512552468480, nr: 32, iocbpp: 0x7fca7d0cebe0) = 32 174k IOPS (+3.6%), IOThread syscalls: 9809.566 ( 0.036 ms): IO iothread1/623061 io_submit(ctx_id: 140539805028352, nr: 32, iocbpp: 0x7fd0cdd62be0) = 32 9809.625 ( 0.001 ms): IO iothread1/623061 write(fd: 103, buf: 0x5647cfba5f58, count: 8) = 8 9809.627 ( 0.002 ms): IO iothread1/623061 write(fd: 104, buf: 0x5647cfba5f58, count: 8) = 8 9809.663 ( 0.036 ms): IO iothread1/623061 io_submit(ctx_id: 140539805028352, nr: 32, iocbpp: 0x7fd0d0388b50) = 32 Notice that ppoll(2) and eventfd read(2) syscalls are eliminated because the IOThread stays in polling mode instead of falling back to file descriptor monitoring. As usual, polling is not implemented on Windows so this patch ignores the new io_poll_read() callback in aio-win32.c. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20211207132336.36627-2-stefanha@redhat.com [Fixed up aio_set_event_notifier() calls in tests/unit/test-fdmon-epoll.c added after this series was queued. --Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2021-12-07 14:23:31 +01:00
NULL, NULL, vu_fd_watch);
}
aio_co_schedule(ctx, server->co_trip);
}
/* Called with server->ctx acquired */
void vhost_user_server_detach_aio_context(VuServer *server)
{
if (server->sioc) {
VuFdWatch *vu_fd_watch;
QTAILQ_FOREACH(vu_fd_watch, &server->vu_fd_watches, next) {
aio_set_fd_handler(server->ctx, vu_fd_watch->fd, true,
aio-posix: split poll check from ready handler Adaptive polling measures the execution time of the polling check plus handlers called when a polled event becomes ready. Handlers can take a significant amount of time, making it look like polling was running for a long time when in fact the event handler was running for a long time. For example, on Linux the io_submit(2) syscall invoked when a virtio-blk device's virtqueue becomes ready can take 10s of microseconds. This can exceed the default polling interval (32 microseconds) and cause adaptive polling to stop polling. By excluding the handler's execution time from the polling check we make the adaptive polling calculation more accurate. As a result, the event loop now stays in polling mode where previously it would have fallen back to file descriptor monitoring. The following data was collected with virtio-blk num-queues=2 event_idx=off using an IOThread. Before: 168k IOPS, IOThread syscalls: 9837.115 ( 0.020 ms): IO iothread1/620155 io_submit(ctx_id: 140512552468480, nr: 16, iocbpp: 0x7fcb9f937db0) = 16 9837.158 ( 0.002 ms): IO iothread1/620155 write(fd: 103, buf: 0x556a2ef71b88, count: 8) = 8 9837.161 ( 0.001 ms): IO iothread1/620155 write(fd: 104, buf: 0x556a2ef71b88, count: 8) = 8 9837.163 ( 0.001 ms): IO iothread1/620155 ppoll(ufds: 0x7fcb90002800, nfds: 4, tsp: 0x7fcb9f1342d0, sigsetsize: 8) = 3 9837.164 ( 0.001 ms): IO iothread1/620155 read(fd: 107, buf: 0x7fcb9f939cc0, count: 512) = 8 9837.174 ( 0.001 ms): IO iothread1/620155 read(fd: 105, buf: 0x7fcb9f939cc0, count: 512) = 8 9837.176 ( 0.001 ms): IO iothread1/620155 read(fd: 106, buf: 0x7fcb9f939cc0, count: 512) = 8 9837.209 ( 0.035 ms): IO iothread1/620155 io_submit(ctx_id: 140512552468480, nr: 32, iocbpp: 0x7fca7d0cebe0) = 32 174k IOPS (+3.6%), IOThread syscalls: 9809.566 ( 0.036 ms): IO iothread1/623061 io_submit(ctx_id: 140539805028352, nr: 32, iocbpp: 0x7fd0cdd62be0) = 32 9809.625 ( 0.001 ms): IO iothread1/623061 write(fd: 103, buf: 0x5647cfba5f58, count: 8) = 8 9809.627 ( 0.002 ms): IO iothread1/623061 write(fd: 104, buf: 0x5647cfba5f58, count: 8) = 8 9809.663 ( 0.036 ms): IO iothread1/623061 io_submit(ctx_id: 140539805028352, nr: 32, iocbpp: 0x7fd0d0388b50) = 32 Notice that ppoll(2) and eventfd read(2) syscalls are eliminated because the IOThread stays in polling mode instead of falling back to file descriptor monitoring. As usual, polling is not implemented on Windows so this patch ignores the new io_poll_read() callback in aio-win32.c. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20211207132336.36627-2-stefanha@redhat.com [Fixed up aio_set_event_notifier() calls in tests/unit/test-fdmon-epoll.c added after this series was queued. --Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2021-12-07 14:23:31 +01:00
NULL, NULL, NULL, NULL, vu_fd_watch);
}
qio_channel_detach_aio_context(server->ioc);
}
server->ctx = NULL;
}
bool vhost_user_server_start(VuServer *server,
SocketAddress *socket_addr,
AioContext *ctx,
uint16_t max_queues,
const VuDevIface *vu_iface,
Error **errp)
{
QEMUBH *bh;
block/export: convert vhost-user-blk server to block export API Use the new QAPI block exports API instead of defining our own QOM objects. This is a large change because the lifecycle of VuBlockDev needs to follow BlockExportDriver. QOM properties are replaced by QAPI options objects. VuBlockDev is renamed VuBlkExport and contains a BlockExport field. Several fields can be dropped since BlockExport already has equivalents. The file names and meson build integration will be adjusted in a future patch. libvhost-user should probably be built as a static library that is linked into QEMU instead of as a .c file that results in duplicate compilation. The new command-line syntax is: $ qemu-storage-daemon \ --blockdev file,node-name=drive0,filename=test.img \ --export vhost-user-blk,node-name=drive0,id=export0,unix-socket=/tmp/vhost-user-blk.sock Note that unix-socket is optional because we may wish to accept chardevs too in the future. Markus noted that supported address families are not explicit in the QAPI schema. It is unlikely that support for more address families will be added since file descriptor passing is required and few address families support it. If a new address family needs to be added, then the QAPI 'features' syntax can be used to advertize them. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Acked-by: Markus Armbruster <armbru@redhat.com> Message-id: 20200924151549.913737-12-stefanha@redhat.com [Skip test on big-endian host architectures because this device doesn't support them yet (as already mentioned in a code comment). --Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-09-24 17:15:47 +02:00
QIONetListener *listener;
if (socket_addr->type != SOCKET_ADDRESS_TYPE_UNIX &&
socket_addr->type != SOCKET_ADDRESS_TYPE_FD) {
error_setg(errp, "Only socket address types 'unix' and 'fd' are supported");
return false;
}
listener = qio_net_listener_new();
if (qio_net_listener_open_sync(listener, socket_addr, 1,
errp) < 0) {
object_unref(OBJECT(listener));
return false;
}
bh = qemu_bh_new(restart_listener_bh, server);
/* zero out unspecified fields */
*server = (VuServer) {
.listener = listener,
.restart_listener_bh = bh,
.vu_iface = vu_iface,
.max_queues = max_queues,
.ctx = ctx,
};
qio_net_listener_set_name(server->listener, "vhost-user-backend-listener");
qio_net_listener_set_client_func(server->listener,
vu_accept,
server,
NULL);
QTAILQ_INIT(&server->vu_fd_watches);
return true;
}