On Tue, 28 Nov 2017 14:12:38 +0000 Rick Macklem <rmack...@uoguelph.ca> wrote:
> Konstantin Belousov wrote: > >On Tue, Nov 28, 2017 at 02:26:10PM +0100, Emmanuel Vadot wrote: > >> On Tue, 28 Nov 2017 13:04:28 +0200 > >> Konstantin Belousov <kostik...@gmail.com> wrote: > >> > >> > On Tue, Nov 28, 2017 at 11:41:36AM +0100, Emmanuel Vadot wrote: > >> > > > >> > > Hello, > >> > > > >> > > I would like to switch the vfs.nfsd.issue_delegations sysctl to a > >> > > tunable. > Since it defaults to "disabled", I don't see why a tunable would be necessary? > (Just do nothing and delegations don't happen. If you want the server > to issue delegations, then use the sysctl to turn them on. If you want to > turn > them off again at the server, reboot the server without setting the sysctl.) If you need to reboot to make things working again without delegation this shouldn't be a sysctl. > > > > The reason behind it is recent problem at work on some on our filer > > > > related to NFS. > > > > We use NFSv4 without delegation as we never been able to have good > > > > performance with FreeBSD server and Linux client (we need to do test > > > > again but that's for later). > Delegations are almost never useful, especially with Linux clients. Can you elaborate ? Reading what delegation are I see that this is exactly what I'm looking for to have better performance with NFS for my workload (I only have one client per mount point). > [stuff snipped] > > > Perhaps make nodeleg per-mount flag ? > The sysctl vfs.nfsd.issue_delegations only affects the server. > If you have a FreeBSD client that is mounting a delegations enabled server and > does not want delegations, just don't run the "nfscbd" daemon on the client. > The only time you want the "nfscbd" daemon running is for delegations and > pNFS layouts. (I suppose there is the case of a client using NFSv4.1/pNFS > against > a server with delegations enabled, but since delegations aren't very useful, > I'd just disable delegations on the server for this case.) > > Having a per-mount version of this would be overkill, I think. It would have > to > disable callbacks on the mount point, since there is no way for a client to > say > "don't give me delegations" except disabling callbacks, which the server > requires for delegation issue. > [stuff snipped] > The case where there has never been delegations issued will result in an > empty delegation queue. Maybe this case can be handled without acquiring > the "global NFSv4 state lock", which is what sounds like is causing the > performance issue. Maybe a global counter of how many delegations are > issued that is handled by atomic ops. > --> If it is 0, nfsrv_checkgetattr() can just return without acquiring the > lock. > > I'll take a look at this, rick > _______________________________________________ > freebsd-current@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org" -- Emmanuel Vadot <m...@bidouilliste.com> <m...@freebsd.org> _______________________________________________ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
