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* jiangyiwen (jiangyiwen at huawei.com) wrote:
> On 2018/12/27 3:05, Vivek Goyal wrote:
> > On Wed, Dec 26, 2018 at 10:32:06AM +0800, jiangyiwen wrote:
> >> On 2018/12/11 3:25, Stefan Hajnoczi wrote:
> >>> Dear Kata Containers Community,

<snip>

> >> 3. Why real mmap operation is executed in qemu process instead of libfuse
> >> daemon? I hope the data plane doesn't not need to pass through qemu again.
> > 
> > If libfuse daemon does mmap() in its address space, then how guest kernel
> > will see those mappings. So, IIUC, qemu needs to call mmap().
> > 
> 
> Oh, I know, Can we use huge page or /dev/shm?

Those don't help for this problem;   the issue here is that we need to 
cause the mapping of the file to appear in the guests physical address
space;  if we mapped /dev/shm or hugepages instead then there's no way
to map the file through that - it's just a different mapping.

Dave

> >>
> >> 4. When I use fio with psync, write/read only 20% improve than 9p, I think
> >> psync can be more used than mmap. This user-case may need to improved.
> > 
> > Can you send me your fio job. I want to try it out.
> > 
> 
> fio -filename=/mnt/virtio_fs/file -rw=read -bs=4k -size=6G -iodepth=1 -ioengine=psync -numjobs=1 -group_reporting -name=xxx -time_based -runtime=120
> 
> Thanks,
> Yiwen.
> 
> > Thanks
> > Vivek
> > 
> > .
> > 
> 
> 
> 
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--
Dr. David Alan Gilbert / dgilbert at redhat.com / Manchester, UK