On Wed, 24 Sep 2014, Benjamin Coddington wrote: > Hi Mark, I've often thought about working on a project like this - > usually when I've been trying to keep a number of systems responsive > when there's been one very aggressive client, which typically would be > identified by a single uid, or a uid:ip pair. I think your second > criteria would be the most useful. Thanks Ben. To do uid:ip paid would be similarly possible, but actually we're also interested in uid only -- to balance load between users on a cluster. > I've done absolutely no research on this, but I had thought offhandedly > that a solution might integrate with cgroups somehow. I'm not sure, as this is a server-side thing, there's no real processes to partition in cgroups. > That's not much (less than 2 cents), but I think this feature would be > welcomed warmly by sysadmins running shared NFS systems. Thanks, good to hear. I'd appreciate any input or caveats from anyone on the ideas I posted for implementing this. Thanks -- Mark > On Wed, 24 Sep 2014, Mark Hills wrote: > > > I am looking at possibilities to implement QoS (quality of service) in an > > NFS server -- for a multiuser HPC environment, on NFSv3. > > > > The desire is for a fully loaded server to process requests in some kind > > of "fair share" (like round robin) or priorities based on some attribute; > > eg. uid at the client, request type + origin, or even directory etc. > > > > Criteria could be fairly blunt and specific to our use case to begin with. > > > > I've looked at the code with the following ideas for where to start. > > > > It seems the implementation depends a lot on which attributes to > > share/schedule on: > > > > 1) by client IP: > > > > make use the existing structures > > > > enhance the svc_xprt_enqueue/dequeue process to schedule svc_xprt > > as these are already per-client > > > > 2) by client uid or other RPC attribute: > > > > have svc_recv make multiple calls to svc_handle_xprt > > > > buffer the requests into multiple queues held at svc_pool (re-use > > xpt_deferred?) > > > > 3) by NFS operation, file handle etc.: > > > > most awkward, as there is not buffering of requests at the NFS level > > or shared between threads > > > > perhaps do as (2) but with a function in svc_program to return > > scheduling criteria > > > > It looks like I need to consider the behaviour when there are multiple > > svc_pool (ie. NUMA) > > > > This is the first time I've looked into this code, I'm interested in any > > comments/criticisms or alternatives. > > > > Thanks > > > > -- > > Mark -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
