* jiangyiwen (jiangyiwen@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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