Re: [Libguestfs] Benchmarks of asynch nbdublk
On 08/27/22 19:40, Richard W.M. Jones wrote:
Alright, so final version for now is here:
https://gitlab.com/rwmjones/libnbd/-/tree/nbdublk/ublk
I'm slightly interested to review this, but I'm also OK if we just push
it and call it "initial addition" or "experimental" or whatever (I
don't
think it can regress anything).
For a review, I'd likely need a good amount of time, and also the
"final" version to be on the list. Also, speaking relative to commit
cafc4dbbc8fa, it would be nice to squash / distribute the fixes into the
original patches as appropriate, and maybe to split up the initial code
drop into a gradual build-up of the new feature.
The latter is a lot of extra work, admittedly, I just find it does
wonders to my review throughput. At the same time, I absolutely don't
insist on reviewing this -- I'm perfectly fine if we merge it at once.
Thanks!
Laszlo
I resolved the data corruption problem once I realised that
->handle_event must only retire commands which are on the same queue
(obvious in hindsight). I ran a parallel job overnight where I did
various heavyweight operations repeatedly -- a bunch of git stuff,
large copies, a big compile etc -- on an nbdublk filesystem. It
handled everything perfectly.
Before this can go upstream:
- Does libubdsrv now have a stable API, or could it change?
- We need to enable the device in the Fedora kernel.
- We need libubdsrv + ublk tool in Fedora.
- Possible we need to add tests into the libnbd tree. I couldn't
think of a good way to test this that doesn't require root and
potentially do some horrible stuff to the testing machine.
Rich.