Re: [PATCH v3 12/12] block/qcow2: automatically insert preallocate filter when on FUSE

[Stefan Hajnoczi]

On Mon, Aug 17, 2020 at 12:15:53PM +0300, Vladimir Sementsov-Ogievskiy wrote:
> vstorage has slow allocation, so this patch detect vstorage
> (I hope, we don't use other FUSE filesystems) and inserts preallocate
> filter between qcow2 node and its file child.
> 
> The following test executes more than 10 times faster
> (43.2s -> 3.9s for me) with this patch. (/newssd3 is mount point of
> vstorage, both cs and mds are on same ssd local ssd disk)
> 
>     IMG=/newssd3/z
>     FILE_OPTS=file.filename=$IMG
>     COUNT=15000
>     CHUNK=64K
>     CLUSTER=1M
>     rm -f $IMG
>     ./qemu-img create -f qcow2 -o cluster_size=$CLUSTER $IMG 1G
>     ./qemu-img bench -c $COUNT -d 1 -s $CHUNK -w -t none -f qcow2 $IMG

Kevin's input is needed here. I think the philosophy is that nodes are
not automatically inserted. The user should define the graph explicitly.
The management tool would be responsible for configuring a preallocate
filter node.

signature.asc
Description: PGP signature