Sluggish performance on head r311648

I'v been noticing lately sluggish performance, maybe zfs? First noticed
this a few days ago right after upgrading on Jan 7th to r311648 and the
last upgrade before that was around dec 30-jan 1 (not sure of rev). Decided
to upgrade again today. I usually build and install head every week or two,
but I have been extremely busy the past couple months.

FreeBSD U1 12.0-CURRENT FreeBSD 12.0-CURRENT #16 r311903: Tue Jan 10
17:20:11 EST 2017 amd64

Normally when one of my services scans a few directories it takes about 15
seconds tops, it has been taking several minutes. I want to note that this
service is running inside a jail with vnet enabled. Also the directory it
scans is a nullfs to a dataset. This is just one of the many side effects
i'v been noticing, another is extremely slow reads with bhyve+zvol.
Starting to wonder if it maybe hardware related.

I decided to check commits log before posting and not much has happened to
zfs recently other than, Add missed vfs.zfs.zfetch.max_idistance in
r309833, and 309714 which doesn't really look related (could be wrong). But
these were committed about a month ago so that is not likely the case.


Anyone else experiences similar results as of recent?


Sorry for being noise if this is hardware related.