Re: [PATCH v3 0/4] virtio-blk: use blk_io_plug_call() instead of notification BH

[Kevin Wolf <kwolf@xxxxxxxxxx>]

Am 13.09.2023 um 22:00 hat Stefan Hajnoczi geschrieben:
> 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 - Remove outdated #include [Ilya]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

Thanks, applied to the block branch.

Kevin