Re: [PATCH] hw/nvme: Add iothread support

[Klaus Jensen <its@irrelevant.dk>]

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On Jul 20 17:00, Jinhao Fan wrote:
> Add an option "iothread=x" to do emulation in a seperate iothread.
> This improves the performance because QEMU's main loop is responsible
> for a lot of other work while iothread is dedicated to NVMe emulation.
> Moreover, emulating in iothread brings the potential of polling on
> SQ/CQ doorbells, which I will bring up in a following patch.
> 
> Iothread can be enabled by:
>  -object iothread,id=nvme0 \
>  -device nvme,iothread=nvme0 \
> 
> Performance comparisons (KIOPS):
> 
> QD         1   4  16  64
> QEMU      41 136 242 338
> iothread  53 155 245 309
> 
> Signed-off-by: Jinhao Fan <fanjinhao21s@ict.ac.cn>
> ---
>  hw/nvme/ctrl.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++----
>  hw/nvme/ns.c   | 19 +++++++++---
>  hw/nvme/nvme.h |  6 +++-
>  3 files changed, 95 insertions(+), 10 deletions(-)
> 

Jinhao,

Are you gonna respin this based on the irqfd patches? I suggest you just
add this work on top and post a series that is irqfd+iothread. Then, if
we find the irqfd ready for merge, we can pick that up for the next
release cycle early and continue on iothread work.

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