This series of performance enhancements brings iothread and polling capabilities to qemu-nvme. The first two patches implements support for irqfd, which solves thread safety problems for interrupt emulation outside the main loop thread. The third patch adds support for emulating NVMe IO queues in a dedicated iothread, which avoid interference from other devices running on the main loop thread. The fourth patch implements SQ and CQ pollers, thus enabling polling on SQ and CQ.
After all these optimizations, our performance becomes similar to virtio-blk. Comparison (KIOPS): QD 1 4 16 64 virtio-blk 59 185 260 256 nvme 53 155 245 309 virtio-blk-polling 88 212 210 213 nvme-polling 123 165 189 191 Changes since v2: - Add polling support - Do not set up MSI-X masking handlers when irq-eventfd is off Changes since v1: - Avoid duplicate initilization of cq timer Jinhao Fan (4): hw/nvme: support irq(de)assertion with eventfd hw/nvme: use KVM irqfd when available hw/nvme: add iothread support hw/nvme: add polling support hw/nvme/ctrl.c | 394 ++++++++++++++++++++++++++++++++++++++++--- hw/nvme/ns.c | 21 ++- hw/nvme/nvme.h | 13 +- hw/nvme/trace-events | 3 + 4 files changed, 401 insertions(+), 30 deletions(-) -- 2.25.1
