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Re: Some performance numbers for virtiofs, DAX and virtio-9p
From: |
Miklos Szeredi |
Subject: |
Re: Some performance numbers for virtiofs, DAX and virtio-9p |
Date: |
Thu, 10 Dec 2020 20:29:21 +0100 |
On Thu, Dec 10, 2020 at 5:11 PM Vivek Goyal <vgoyal@redhat.com> wrote:
> Conclusion
> -----------
> - virtiofs DAX seems to help a lot in many workloads.
>
> Note, DAX performance well only if data fits in cache window. My total
> data is 16G and cache window size is 16G as well. If data is larger
> than DAX cache window, then performance of dax suffers a lot. Overhead
> of reclaiming old mapping and setting up a new one is very high.
Which begs the question: what is the optimal window size?
What is the cost per GB of window to the host and guest?
Could we measure at what point does a large window size actually make
performance worse?
>
> NAME WORKLOAD Bandwidth IOPS
> 9p-none seqread-psync 98.6mb 24.6k
> 9p-mmap seqread-psync 97.5mb 24.3k
> 9p-loose seqread-psync 91.6mb 22.9k
> vtfs-none seqread-psync 98.4mb 24.6k
> vtfs-none-dax seqread-psync 660.3mb 165.0k
> vtfs-auto seqread-psync 650.0mb 162.5k
> vtfs-auto-dax seqread-psync 703.1mb 175.7k
> vtfs-always seqread-psync 671.3mb 167.8k
> vtfs-always-dax seqread-psync 687.2mb 171.8k
>
> 9p-none seqread-psync-multi 397.6mb 99.4k
> 9p-mmap seqread-psync-multi 382.7mb 95.6k
> 9p-loose seqread-psync-multi 350.5mb 87.6k
> vtfs-none seqread-psync-multi 360.0mb 90.0k
> vtfs-none-dax seqread-psync-multi 2281.1mb 570.2k
> vtfs-auto seqread-psync-multi 2530.7mb 632.6k
> vtfs-auto-dax seqread-psync-multi 2423.9mb 605.9k
> vtfs-always seqread-psync-multi 2535.7mb 633.9k
> vtfs-always-dax seqread-psync-multi 2406.1mb 601.5k
Seems like in all the -multi tests 9p-none performs consistently
better than vtfs-none. Could that be due to the single queue?
Thanks,
Miklos
- Some performance numbers for virtiofs, DAX and virtio-9p, Vivek Goyal, 2020/12/10
- Re: Some performance numbers for virtiofs, DAX and virtio-9p,
Miklos Szeredi <=
- Re: Some performance numbers for virtiofs, DAX and virtio-9p, Vivek Goyal, 2020/12/11
- Re: Some performance numbers for virtiofs, DAX and virtio-9p, Dr. David Alan Gilbert, 2020/12/11
- Re: Some performance numbers for virtiofs, DAX and virtio-9p, Vivek Goyal, 2020/12/11
- Re: Some performance numbers for virtiofs, DAX and virtio-9p, Vivek Goyal, 2020/12/11
- Re: Some performance numbers for virtiofs, DAX and virtio-9p, Dr. David Alan Gilbert, 2020/12/11
- Re: Some performance numbers for virtiofs, DAX and virtio-9p, Vivek Goyal, 2020/12/11