On Sun, Aug 16, 2020 at 04:46:00PM -0400, Chuck Lever wrote:
> Hi Bruce-
>
> > On Aug 11, 2020, at 9:31 AM, Chuck Lever <chuck.lever@xxxxxxxxxx> wrote:
> >
> >> On Aug 10, 2020, at 4:10 PM, Bruce Fields <bfields@xxxxxxxxxxxx> wrote:
> >>
> >> On Mon, Aug 10, 2020 at 04:01:00PM -0400, Chuck Lever wrote:
> >>> Roughly the same result with this patch as with the first one. The
> >>> first one is a little better. Plus, I think the Solaris NFS server
> >>> hands out write delegations on v4.0, and I haven't heard of a
> >>> significant issue there. It's heuristics may be different, though.
> >>>
> >>> So, it might be that NFSv4.0 has always run significantly slower. I
> >>> will have to try a v5.4 or older server to see.
> >>
> >> Oh, OK, I was assuming this was a regression.
> >
> > Me too. Looks like it is: NFSv4.0 always runs slower, but I see
> > it get significantly worse between v5.4 and 5.5. I will post more
> > quantified results soon.
>
> It took me a while to get plausible bisection results. The problem
> appears in the midst of the NFSD filecache patches merged in v5.4.
Well, that's interesting.
> In order of application:
>
> 5920afa3c85f ("nfsd: hook nfsd_commit up to the nfsd_file cache")
> 961.68user 5252.40system 20:12.30elapsed 512%CPU, 2541 DELAY errors
> These results are similar to v5.3.
>
> fd4f83fd7dfb ("nfsd: convert nfs4_file->fi_fds array to use nfsd_files")
> Does not build
>
> eb82dd393744 ("nfsd: convert fi_deleg_file and ls_file fields to nfsd_file")
> 966.92user 5425.47system 33:52.79elapsed 314%CPU, 1330 DELAY errors
>
> Can you take a look and see if there's anything obvious?
Unfortunately nothing about the file cache code is very obvious to me.
I'm looking at it....
It adds some new nfserr_jukebox returns in nfsd_file_acquire. Those
mostly look like kmalloc failures, the one I'm not sure about is the
NFSD_FILE_HASHED check.
Or maybe it's the lease break there.
--b.
