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[PATCH v3 0/4] virtio-blk: use blk_io_plug_call() instead of notificatio
From: |
Stefan Hajnoczi |
Subject: |
[PATCH v3 0/4] virtio-blk: use blk_io_plug_call() instead of notification BH |
Date: |
Wed, 13 Sep 2023 16:00:41 -0400 |
v3:
- Add comment pointing to API documentation in .c file [Philippe]
- Add virtio_notify_irqfd_deferred_fn trace event [Ilya]
- Remove outdated #include [Ilya]
v2:
- Rename blk_io_plug() to defer_call() and move it to util/ so the net
subsystem can use it [Ilya]
- Add defer_call_begin()/end() to thread_pool_completion_bh() to match Linux
AIO and io_uring completion batching
Replace the seldom-used virtio-blk notification BH mechanism with
blk_io_plug(). This is part of an effort to enable the multi-queue block layer
in virtio-blk. The notification BH was not multi-queue friendly.
The blk_io_plug() mechanism improves fio rw=randread bs=4k iodepth=64 numjobs=8
IOPS by ~9% with a single IOThread and 8 vCPUs (this is not even a multi-queue
block layer configuration) compared to no completion batching. iodepth=1
decreases by ~1% but this could be noise. Benchmark details are available here:
https://gitlab.com/stefanha/virt-playbooks/-/tree/blk_io_plug-irqfd
Stefan Hajnoczi (4):
block: rename blk_io_plug_call() API to defer_call()
util/defer-call: move defer_call() to util/
virtio: use defer_call() in virtio_irqfd_notify()
virtio-blk: remove batch notification BH
MAINTAINERS | 3 +-
include/qemu/defer-call.h | 16 +++
include/sysemu/block-backend-io.h | 4 -
block/blkio.c | 9 +-
block/io_uring.c | 11 ++-
block/linux-aio.c | 9 +-
block/nvme.c | 5 +-
block/plug.c | 159 ------------------------------
hw/block/dataplane/virtio-blk.c | 48 +--------
hw/block/dataplane/xen-block.c | 11 ++-
hw/block/virtio-blk.c | 5 +-
hw/scsi/virtio-scsi.c | 7 +-
hw/virtio/virtio.c | 13 ++-
util/defer-call.c | 156 +++++++++++++++++++++++++++++
util/thread-pool.c | 5 +
block/meson.build | 1 -
hw/virtio/trace-events | 1 +
util/meson.build | 1 +
18 files changed, 231 insertions(+), 233 deletions(-)
create mode 100644 include/qemu/defer-call.h
delete mode 100644 block/plug.c
create mode 100644 util/defer-call.c
--
2.41.0
- [PATCH v3 0/4] virtio-blk: use blk_io_plug_call() instead of notification BH,
Stefan Hajnoczi <=
- [PATCH v3 2/4] util/defer-call: move defer_call() to util/, Stefan Hajnoczi, 2023/09/13
- [PATCH v3 1/4] block: rename blk_io_plug_call() API to defer_call(), Stefan Hajnoczi, 2023/09/13
- [PATCH v3 3/4] virtio: use defer_call() in virtio_irqfd_notify(), Stefan Hajnoczi, 2023/09/13
- [PATCH v3 4/4] virtio-blk: remove batch notification BH, Stefan Hajnoczi, 2023/09/13
- Re: [PATCH v3 0/4] virtio-blk: use blk_io_plug_call() instead of notification BH, Michael S. Tsirkin, 2023/09/13