[Xen-API] [PATCH 2 of 4] CA-35397: reduce the number of calls to domain_getinfo{, list} by passing the values around in the monitor module and by observing that the domain info record has the UUID in it-- no need to query it again

[David Scott <dave.scott@xxxxxxxxxxxxx>]

# HG changeset patch
# User David Scott <dave.scott@xxxxxxxxxxxxx>
# Date 1259589189 0
# Node ID 2c13b21ff2d436e451a91009cc0676124df8e3cd
# Parent  c90daafe028b57f2b597c4a8961355e23770ff93
CA-35397: reduce the number of calls to domain_getinfo{,list} by passing the 
values around in the monitor module and by observing that the domain info 
record has the UUID in it-- no need to query it again.

This reduces hypercall spam in the simulator a lot.

Signed-off-by: David Scott <dave.scott@xxxxxxxxxxxxx>

diff -r c90daafe028b -r 2c13b21ff2d4 ocaml/xapi/monitor.ml
--- a/ocaml/xapi/monitor.ml     Mon Nov 30 13:53:08 2009 +0000
+++ b/ocaml/xapi/monitor.ml     Mon Nov 30 13:53:09 2009 +0000
@@ -53,6 +53,12 @@
 let uncooperative_domains: (int, unit) Hashtbl.t = Hashtbl.create 20
 let uncooperative_domains_m = Mutex.create ()
 
+let uuid_of_domid domains domid = 
+  let domid_to_uuid = List.map (fun di -> di.Xc.domid, Uuid.uuid_of_int_array 
di.Xc.handle) domains in
+  if List.mem_assoc domid domid_to_uuid
+  then Uuid.string_of_uuid (List.assoc domid domid_to_uuid)
+  else failwith (Printf.sprintf "Failed to find uuid corresponding to domid: 
%d" domid)
+
 let get_uncooperative_domains () = 
   let domids = Mutex.execute uncooperative_domains_m (fun () -> Hashtbl.fold 
(fun domid _ acc -> domid::acc) uncooperative_domains []) in
   let dis = Xc.with_intf (fun xc -> Xc.domain_getinfolist xc 0) in
@@ -66,13 +72,12 @@
 
 (* This function is used both for getting vcpu stats and for getting the uuids 
of the
    VMs present on this host *)
-let update_vcpus xc =
-  let doms = Xc.domain_getinfolist xc 0 in
+let update_vcpus xc doms =
   List.fold_left (fun (dss,uuids,domids) dom ->
     let domid = dom.Xc.domid in
     let maxcpus = dom.Xc.max_vcpu_id + 1 in
-    let uuid=uuid_of_domid domid in
-    
+    let uuid = Uuid.string_of_uuid (Uuid.uuid_of_int_array dom.Xc.handle) in
+
     let rec cpus i dss = 
       if i>=maxcpus then dss else 
        let vcpuinfo = Xc.domain_get_vcpuinfo xc domid i in
@@ -123,13 +128,12 @@
       ~ty:Rrd.Derive ~default:true ~transform:(fun x -> 1.0 -. x) 
())::acc,i+1)) ([],0) newinfos in
   dss
 
-let update_memory __context xc = 
-       let doms = Xc.domain_getinfolist xc 0 in
+let update_memory __context xc doms = 
        List.fold_left (fun acc dom ->
                let domid = dom.Xc.domid in
                let kib = Xc.pages_to_kib (Int64.of_nativeint 
dom.Xc.total_memory_pages) in 
                let memory = Int64.mul kib 1024L in
-               let uuid = uuid_of_domid domid in
+               let uuid = Uuid.string_of_uuid (Uuid.uuid_of_int_array 
dom.Xc.handle) in
                let main_mem_ds = 
                  (VM uuid,
                  ds_make ~name:"memory" ~description:"Memory currently 
allocated to VM"
@@ -174,7 +178,7 @@
        mutable rx_errors: int64; (* error received *)
 }
 
-let update_netdev () =
+let update_netdev doms =
   let devs = ref [] in
 
   let standardise_name name =
@@ -237,7 +241,7 @@
          (fun d1 d2 -> d1, d2) in
        let vif_name = Printf.sprintf "vif_%d" d2 in
        (* Note: rx and tx are the wrong way round because from dom0 we see the 
vms backwards *)
-       let uuid=uuid_of_domid d1 in
+       let uuid=uuid_of_domid doms d1 in
        (VM uuid,
        ds_make ~name:(vif_name^"_tx")
          ~description:("Bytes per second transmitted on virtual interface 
number '"^(string_of_int d2)^"'")
@@ -303,7 +307,7 @@
 (* disk related code                                 *)
 (*****************************************************)
 
-let update_vbds () =
+let update_vbds doms =
   let read_int_file file =
     let v = ref 0L in
     try Unixext.readfile_line (fun l -> v := Int64.of_string l) file; !v
@@ -344,7 +348,7 @@
        correspond to an active domain uuid. Skip these for now. *)
     let newacc = 
       try
-       let uuid=uuid_of_domid domid in
+       let uuid=uuid_of_domid doms domid in
        (VM uuid,
        ds_make ~name:(vbd_name^"_write") ~description:("Writes to device 
'"^device_name^"' in bytes per second")
          ~value:(Rrd.VT_Int64 wr_bytes) ~ty:Rrd.Derive ~min:0.0 ~default:true 
~units:"bytes per second" ())::
@@ -426,11 +430,12 @@
        default
       end in
   Mutex.execute lock (fun () ->
-    let timestamp = Unix.gettimeofday() in
-    let my_rebooting_vms = StringSet.fold (fun uuid acc -> uuid::acc) 
!rebooting_vms [] in
-    let (vifs,pifs) = try update_netdev() with e -> (debug "Exception in 
update_netdev(). Defaulting value for vifs/pifs: %s" (Printexc.to_string e); 
([],[]))  in
-    with_xc (fun xc ->
-      let (vcpus,uuids,domids) = update_vcpus xc in
+       with_xc (fun xc ->
+         let domains = Xc.domain_getinfolist xc 0 in
+      let timestamp = Unix.gettimeofday() in
+      let my_rebooting_vms = StringSet.fold (fun uuid acc -> uuid::acc) 
!rebooting_vms [] in
+      let (vifs,pifs) = try update_netdev domains with e -> (debug "Exception 
in update_netdev(). Defaulting value for vifs/pifs: %s" (Printexc.to_string e); 
([],[]))  in
+      let (vcpus,uuids,domids) = update_vcpus xc domains in
       Xapi_guest_agent.sync_cache domids;
       Helpers.remove_other_keys memory_targets domids;
       Helpers.remove_other_keys uncooperative_domains domids;
@@ -441,9 +446,9 @@
         vcpus;
        vifs;
        handle_exn "update_pcpus" (fun ()->update_pcpus xc) [];
-       handle_exn "update_vbds" (fun ()->update_vbds()) [];
+       handle_exn "update_vbds" (fun ()->update_vbds domains) [];
        handle_exn "update_loadavg" (fun ()-> [ update_loadavg () ]) [];
-       handle_exn "update_memory" (fun ()->update_memory __context xc) 
[]],uuids,pifs,timestamp,my_rebooting_vms)
+       handle_exn "update_memory" (fun ()->update_memory __context xc domains) 
[]],uuids,pifs,timestamp,my_rebooting_vms)
     )
   )
 
1 file changed, 23 insertions(+), 18 deletions(-)
ocaml/xapi/monitor.ml |   41 +++++++++++++++++++++++------------------

Attachment: xen-api.hg-4.patch
Description: Text Data

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