v4: - Squash fixup commit properly this time >_< [Peter] v3: - Use vq_aio_context[VIRTIO_SCSI_VQ_NUM_FIXED] as the AioContext for the Block Backend [Kevin] v2: - Only expose cmd vqs via iothread-vq-mapping [Kevin, Peter]
Implement --device virtio-scsi-pci,iothread-vq-mapping= support so that virtqueues can be assigned to different IOThreads. This improves SMP guest scalability where I/O-intensive applications can become bottlenecked on a single IOThread. The following benchmark results show the effect of iothread-vq-mapping. fio randread 4k iodepth=64 results from a 4 vCPU guest with an Intel P4800X SSD: iothreads IOPS ------------------------------ 1 189576 2 312698 4 346744 The virtio-scsi device model and core SCSI emulation currently assume that requests are processed in a single AioContext. This patch series goes about modifying this as follows: scsi-disk: drop unused SCSIDiskState->bh field dma: use current AioContext for dma_blk_io() Make dma-helpers.c support the QEMU multi-queue block layer by using qemu_get_current_aio_context(). scsi: track per-SCSIRequest AioContext scsi: introduce requests_lock Make the core SCSI emulation code support processing requests in multiple AioContexts by protecting the per-SCSIDevice requests list. virtio-scsi: introduce event and ctrl virtqueue locks virtio-scsi: protect events_dropped field virtio-scsi: perform TMFs in appropriate AioContexts Make the virtio-scsi emulation code support processing requests in multiple AioContexts. The event and ctrl virtqueues can interact with multiple AioContexts. Especially the SCSI Task Management Functions (TMFs) handled by the ctrl virtqueue need to be made thread-safe. virtio-blk: extract cleanup_iothread_vq_mapping() function virtio-blk: tidy up iothread_vq_mapping functions virtio: extract iothread-vq-mapping.h API virtio-scsi: add iothread-vq-mapping parameter Port over the iothread-vq-mapping qdev property from virtio-blk to virtio-scsi. virtio-scsi: handle ctrl virtqueue in main loop Simplify TMF handling now that there is no longer a single AioContext where all requests are processed. virtio-scsi: only expose cmd vqs via iothread-vq-mapping Make the user interface more intuitive. Stefan Hajnoczi (13): scsi-disk: drop unused SCSIDiskState->bh field dma: use current AioContext for dma_blk_io() scsi: track per-SCSIRequest AioContext scsi: introduce requests_lock virtio-scsi: introduce event and ctrl virtqueue locks virtio-scsi: protect events_dropped field virtio-scsi: perform TMFs in appropriate AioContexts virtio-blk: extract cleanup_iothread_vq_mapping() function virtio-blk: tidy up iothread_vq_mapping functions virtio: extract iothread-vq-mapping.h API virtio-scsi: add iothread-vq-mapping parameter virtio-scsi: handle ctrl virtqueue in main loop virtio-scsi: only expose cmd vqs via iothread-vq-mapping include/hw/scsi/scsi.h | 8 +- include/hw/virtio/iothread-vq-mapping.h | 45 ++ include/hw/virtio/virtio-scsi.h | 15 +- include/system/dma.h | 3 +- hw/block/virtio-blk.c | 132 +----- hw/ide/core.c | 3 +- hw/ide/macio.c | 3 +- hw/scsi/scsi-bus.c | 121 ++++-- hw/scsi/scsi-disk.c | 24 +- hw/scsi/virtio-scsi-dataplane.c | 103 +++-- hw/scsi/virtio-scsi.c | 542 ++++++++++++++---------- hw/virtio/iothread-vq-mapping.c | 131 ++++++ system/dma-helpers.c | 8 +- hw/virtio/meson.build | 1 + 14 files changed, 683 insertions(+), 456 deletions(-) create mode 100644 include/hw/virtio/iothread-vq-mapping.h create mode 100644 hw/virtio/iothread-vq-mapping.c -- 2.48.1
