qemu/util
Stefan Hajnoczi 84d61e5f36 virtio: use defer_call() in virtio_irqfd_notify()
virtio-blk and virtio-scsi invoke virtio_irqfd_notify() to send Used
Buffer Notifications from an IOThread. This involves an eventfd
write(2) syscall. Calling this repeatedly when completing multiple I/O
requests in a row is wasteful.

Use the defer_call() API to batch together virtio_irqfd_notify() calls
made during thread pool (aio=threads), Linux AIO (aio=native), and
io_uring (aio=io_uring) completion processing.

Behavior is unchanged for emulated devices that do not use
defer_call_begin()/defer_call_end() since defer_call() immediately
invokes the callback when called outside a
defer_call_begin()/defer_call_end() region.

fio rw=randread bs=4k iodepth=64 numjobs=8 IOPS increases by ~9% with a
single IOThread and 8 vCPUs. iodepth=1 decreases by ~1% but this could
be noise. Detailed performance data and configuration specifics are
available here:
https://gitlab.com/stefanha/virt-playbooks/-/tree/blk_io_plug-irqfd

This duplicates the BH that virtio-blk uses for batching. The next
commit will remove it.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230913200045.1024233-4-stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-31 15:42:14 +01:00
..
aio-posix.c aio: remove aio_disable_external() API 2023-05-30 17:37:26 +02:00
aio-posix.h aio: remove aio_disable_external() API 2023-05-30 17:37:26 +02:00
aio-wait.c aio-wait: avoid AioContext lock in aio_wait_bh_oneshot() 2023-05-10 14:15:13 +02:00
aio-win32.c aio: remove aio_disable_external() API 2023-05-30 17:37:26 +02:00
aiocb.c
async.c aio: remove aio_disable_external() API 2023-05-30 17:37:26 +02:00
atomic64.c osdep: Move memalign-related functions to their own header 2022-03-07 13:16:49 +00:00
base64.c
bitmap.c migration: Use non-atomic ops for clear log bitmap 2022-11-21 11:58:10 +01:00
bitops.c replace TABs with spaces 2023-03-20 12:43:50 +01:00
block-helpers.c
block-helpers.h
buffer.c
bufferiszero.c util/bufferiszero: Use i386 host/cpuinfo.h 2023-05-23 16:51:13 -07:00
cacheflush.c util/cacheflush: Avoid possible redundant dcache flush on Darwin 2023-06-13 11:28:58 +02:00
compatfd.c util: replace pipe()+cloexec with g_unix_open_pipe() 2022-05-03 15:18:14 +04:00
coroutine-sigaltstack.c osdep: set _FORTIFY_SOURCE=2 when optimization is enabled 2023-10-04 09:52:06 -04:00
coroutine-ucontext.c osdep: set _FORTIFY_SOURCE=2 when optimization is enabled 2023-10-04 09:52:06 -04:00
coroutine-windows.c build: move coroutine backend selection to meson 2023-05-18 08:53:52 +02:00
cpuinfo-aarch64.c *: Delete checks for old host definitions 2023-09-19 13:20:54 -04:00
cpuinfo-i386.c host/include/i386: Implement clmul.h 2023-09-15 13:57:00 +00:00
cpuinfo-ppc.c util: spelling fixes 2023-08-31 19:47:43 +02:00
crc32c.c igb: Implement Rx SCTP CSO 2023-05-23 15:20:15 +08:00
crc-ccitt.c
cutils.c cutils: Fix get_relocated_path on Windows 2023-10-19 23:13:27 +02:00
dbus.c
defer-call.c util/defer-call: move defer_call() to util/ 2023-10-31 15:41:42 +01:00
drm.c
envlist.c replace TABs with spaces 2023-03-20 12:43:50 +01:00
error-report.c util/error: add G_GNUC_PRINTF for various functions 2023-01-11 10:44:34 +01:00
error.c util/error: Fix use-after-free errors reported by Coverity 2023-04-06 12:38:42 -04:00
event_notifier-posix.c Replace qemu_pipe() with g_unix_open_pipe() 2022-05-03 15:17:56 +04:00
event_notifier-win32.c Remove qemu-common.h include from most units 2022-04-06 14:31:55 +02:00
fdmon-epoll.c aio: remove aio_disable_external() API 2023-05-30 17:37:26 +02:00
fdmon-io_uring.c aio-posix: zero out io_uring sqe user_data 2023-08-30 07:39:59 -04:00
fdmon-poll.c aio: remove aio_disable_external() API 2023-05-30 17:37:26 +02:00
fifo8.c
filemonitor-inotify.c
filemonitor-stub.c
getauxval.c
guest-random.c util/guest-random: Clean up global variable shadowing 2023-10-06 13:27:48 +02:00
hbitmap.c hbitmap: fix hbitmap_status() return value for first dirty bit case 2023-02-17 14:34:24 +01:00
hexdump.c include: move C/util-related declarations to cutils.h 2022-04-06 14:31:43 +02:00
host-utils.c host-utils: Implemented signed 256-by-128 division 2022-06-20 08:38:58 -03:00
id.c
int128.c include/qemu/int128: Use Int128 structure for TCI 2023-02-04 06:19:42 -10:00
interval-tree.c util/interval-tree: Check root for null in interval_tree_iter_first 2023-08-09 09:26:32 -07:00
iov.c util/iov: Avoid dynamic stack allocation 2023-09-07 20:32:11 -05:00
iova-tree.c util: accept iova_tree_remove_parameter by value 2022-09-02 10:22:39 +08:00
keyval.c include: add qemu/keyval.h 2022-04-21 17:03:51 +04:00
lockcnt.c
log.c util/log: re-allow switching away from stderr log file 2023-10-07 19:02:33 +02:00
main-loop.c util: spelling fixes 2023-08-31 19:47:43 +02:00
memalign.c osdep: Move memalign-related functions to their own header 2022-03-07 13:16:49 +00:00
memfd.c
meson.build util/defer-call: move defer_call() to util/ 2023-10-31 15:41:42 +01:00
mmap-alloc.c util/mmap-alloc: qemu_fd_getfs() 2023-04-24 11:29:00 +02:00
module.c module: add Error arguments to module_load and module_load_qom 2022-11-06 09:48:50 +01:00
notify.c
nvdimm-utils.c
osdep.c error handling: Use RETRY_ON_EINTR() macro where applicable 2023-01-09 13:50:47 +01:00
oslib-posix.c util: Delete checks for old host definitions 2023-09-15 05:26:50 -07:00
oslib-win32.c win32: avoid discarding the exception handler 2023-10-03 15:05:20 +04:00
path.c
qdist.c util: spelling fixes 2023-08-31 19:47:43 +02:00
qemu-co-shared-resource.c co-shared-resource: protect with a mutex 2021-06-25 14:24:24 +03:00
qemu-co-timeout.c util: add qemu-co-timeout 2022-06-29 10:56:12 +03:00
qemu-config.c error: Drop superfluous #include "qapi/qmp/qerror.h" 2023-02-23 13:56:14 +01:00
qemu-coroutine-io.c aio: remove aio_disable_external() API 2023-05-30 17:37:26 +02:00
qemu-coroutine-lock.c atomics: eliminate mb_read/mb_set 2023-06-06 09:42:14 +02:00
qemu-coroutine-sleep.c coroutine: Clean up superfluous inclusion of qemu/coroutine.h 2023-01-19 10:18:28 +01:00
qemu-coroutine.c meson: do not use set10 2023-10-17 15:20:53 +02:00
qemu-option.c qemu-option: Allow deleting opts during qemu_opts_foreach() 2021-10-15 16:11:22 +02:00
qemu-print.c
qemu-progress.c include: move progress API to qemu-progress.h 2022-04-06 14:31:43 +02:00
qemu-sockets.c util: spelling fixes 2023-08-31 19:47:43 +02:00
qemu-thread-common.h
qemu-thread-posix.c qemu-thread-posix: cleanup, fix, document QemuEvent 2023-03-07 12:38:40 +01:00
qemu-thread-win32.c qemu-thread-win32: cleanup, fix, document QemuEvent 2023-03-07 12:38:40 +01:00
qemu-timer-common.c
qemu-timer.c qemu-timer: Skip empty timer lists before locking in qemu_clock_deadline_ns_all 2022-06-21 09:24:34 -07:00
qht.c util/qht: use striped locks under TSAN 2023-02-02 11:48:20 +00:00
qsp.c accel/tcg: include cs_base in our hash calculations 2023-06-01 11:05:05 -04:00
qtree.c tcg: use QTree instead of GTree 2023-03-28 15:23:10 -07:00
range.c
rcu.c util: spelling fixes 2023-08-31 19:47:43 +02:00
readline.c readline: Extract readline_add_completion_of() from monitor 2023-02-04 07:56:54 +01:00
selfmap.c util/selfmap: Use dev_t and ino_t in MapInfo 2023-09-01 13:34:03 -07:00
stats64.c stat64: Add stat64_set() operation 2023-04-27 16:39:43 +02:00
sys_membarrier.c
systemd.c systemd: Also clear LISTEN_FDNAMES during systemd socket activation 2023-05-03 14:00:08 -05:00
thread-context.c qapi: Use returned bool to check for failure (again) 2022-12-14 16:19:35 +01:00
thread-pool.c virtio: use defer_call() in virtio_irqfd_notify() 2023-10-31 15:42:14 +01:00
throttle.c throttle: use THROTTLE_MAX/ARRAY_SIZE for hard code 2023-08-29 10:49:24 +02:00
timed-average.c
trace-events console/win32: allocate shareable display surface 2023-06-27 17:08:56 +02:00
trace.h
transactions.c transactions: Invoke clean() after everything else 2021-11-16 09:43:44 +01:00
unicode.c
uri.c Updated the FSF address to <https://www.gnu.org/licenses/> 2023-02-27 09:15:39 +01:00
userfaultfd.c util/userfaultfd: Support /dev/userfaultfd 2023-02-11 16:51:09 +01:00
uuid.c util/uuid: add a hash function 2023-10-04 18:15:06 -04:00
vfio-helpers.c util/vfio-helpers: Use g_file_read_link() 2023-05-24 09:21:22 +02:00
vhost-user-server.c util/vhost-user-server: Clean up local variable shadowing 2023-09-29 10:07:16 +02:00
yank.c