[libvirt] [PATCH 1/1 V4] virt-top: correct "virt-top -1" command via cpuacct cgroup

Old "virt-top -1" is not correct, its output is generated by guess: use average usage for pinned physical CPUs. example(old "virt-top -1"): PHYCPU %CPU rhel6 Windows 0 0.6 0.1= 0.5= 1 0.6 0.1= 0.5=# 2 0.6 0.1= 0.5= 3 0.6 0.1=# 0.5= The output almost makes no sense(all the value are just average, not real). This is new implement, it use cpuacct cgroup to gain *real* physical usages via cpuacct cgroup by virDomainGetCPUStats() API. new result: PHYCPU %CPU rhel6 Windows 0 1.3 0.3 1.0 1 2.3 0.3 2.0 2 2.2 0.5 1.7 3 2.5 0.4 2.1 PHYCPU %CPU rhel6 Windows 0 1.7 0.4 1.3 1 3.6 1.0 2.7 2 1.6 0.4 1.2 3 4.8 3.1 1.7 Note: average flag(=) is dropped, there is not average value in here. Note: running flag(#) is dropped, because if the value is not empty, it means the guest was once running in the physical CPU in this period between updates. Changed from V3: use new virDomainGetCPUStats() libvirt-API. add a new function find_usages_from_stats() to gain cpu usages. Acked-by: "Richard W.M. Jones" <rjones(a)redhat.com&gt; Signed-off-by: Lai Jiangshan <laijs(a)cn.fujitsu.com&gt; --- virt-top/virt_top.ml | 80 +++++++++++++++++++------------------------------ 1 files changed, 31 insertions(+), 49 deletions(-) diff --git a/virt-top/virt_top.ml b/virt-top/virt_top.ml index ef5ac67..f7bd072 100644 --- a/virt-top/virt_top.ml +++ b/virt-top/virt_top.ml @@ -446,14 +446,14 @@ let collect, clear_pcpu_display_data = let last_info = Hashtbl.create 13 in let last_time = ref (Unix.gettimeofday ()) in - (* Save vcpuinfo structures across redraws too (only for pCPU display). *) - let last_vcpu_info = Hashtbl.create 13 in + (* Save pcpu_usages structures across redraws too (only for pCPU display). *) + let last_pcpu_usages = Hashtbl.create 13 in let clear_pcpu_display_data () = - (* Clear out vcpu_info used by PCPUDisplay display_mode + (* Clear out pcpu_info used by PCPUDisplay display_mode * when we switch back to TaskDisplay mode. *) - Hashtbl.clear last_vcpu_info + Hashtbl.clear last_pcpu_usages in let collect (conn, _, _, _, _, node_info, _, _) = @@ -652,22 +652,28 @@ let collect, clear_pcpu_display_data = (try let domid = rd.rd_domid in let maplen = C.cpumaplen nr_pcpus in + let cpu_stats = D.get_cpu_stats rd.rd_dom nr_pcpus in + let rec find_usages_from_stats = (function + | ("cpu_time", D.TypedFieldUInt64(usages)) :: _ -> usages + | (_, _) :: params -> find_usages_from_stats params + | [] -> 0L) in + let pcpu_usages = Array.map find_usages_from_stats cpu_stats in let maxinfo = rd.rd_info.D.nr_virt_cpu in let nr_vcpus, vcpu_infos, cpumaps = D.get_vcpus rd.rd_dom maxinfo maplen in - (* Got previous vcpu_infos for this domain? *) - let prev_vcpu_infos = - try Some (Hashtbl.find last_vcpu_info domid) + (* Got previous pcpu_usages for this domain? *) + let prev_pcpu_usages = + try Some (Hashtbl.find last_pcpu_usages domid) with Not_found -> None in - (* Update last_vcpu_info. *) - Hashtbl.replace last_vcpu_info domid vcpu_infos; - - (match prev_vcpu_infos with - | Some prev_vcpu_infos - when Array.length prev_vcpu_infos = Array.length vcpu_infos -> - Some (domid, name, nr_vcpus, vcpu_infos, prev_vcpu_infos, - cpumaps, maplen) + (* Update last_pcpu_usages. *) + Hashtbl.replace last_pcpu_usages domid pcpu_usages; + + (match prev_pcpu_usages with + | Some prev_pcpu_usages + when Array.length prev_pcpu_usages = Array.length pcpu_usages -> + Some (domid, name, nr_vcpus, vcpu_infos, pcpu_usages, + prev_pcpu_usages, cpumaps, maplen) | _ -> None (* ignore missing / unequal length prev_vcpu_infos *) ); with @@ -680,37 +686,15 @@ let collect, clear_pcpu_display_data = (* Rearrange the data into a matrix. Major axis (down) is * pCPUs. Minor axis (right) is domains. At each node we store: * cpu_time (on this pCPU only, nanosecs), - * average? (if set, then cpu_time is an average because the - * vCPU is pinned to more than one pCPU) - * running? (if set, we were instantaneously running on this pCPU) *) - let empty_node = (0L, false, false) in - let pcpus = Array.make_matrix nr_pcpus nr_doms empty_node in + let pcpus = Array.make_matrix nr_pcpus nr_doms 0L in List.iteri ( - fun di (domid, name, nr_vcpus, vcpu_infos, prev_vcpu_infos, - cpumaps, maplen) -> + fun di (domid, name, nr_vcpus, vcpu_infos, pcpu_usages, + prev_pcpu_usages, cpumaps, maplen) -> (* Which pCPUs can this dom run on? *) - for v = 0 to nr_vcpus-1 do - let pcpu = vcpu_infos.(v).D.cpu in (* instantaneous pCPU *) - let nr_poss_pcpus = ref 0 in (* how many pcpus can it run on? *) - for p = 0 to nr_pcpus-1 do - (* vcpu v can reside on pcpu p *) - if C.cpu_usable cpumaps maplen v p then - incr nr_poss_pcpus - done; - let nr_poss_pcpus = Int64.of_int !nr_poss_pcpus in - for p = 0 to nr_pcpus-1 do - (* vcpu v can reside on pcpu p *) - if C.cpu_usable cpumaps maplen v p then - let vcpu_time_on_pcpu = - vcpu_infos.(v).D.vcpu_time - -^ prev_vcpu_infos.(v).D.vcpu_time in - let vcpu_time_on_pcpu = - vcpu_time_on_pcpu /^ nr_poss_pcpus in - pcpus.(p).(di) <- - (vcpu_time_on_pcpu, nr_poss_pcpus > 1L, p = pcpu) - done + for p = 0 to Array.length pcpu_usages - 1 do + pcpus.(p).(di) <- (pcpu_usages.(p) -^ prev_pcpu_usages.(p)) done ) doms; @@ -719,7 +703,7 @@ let collect, clear_pcpu_display_data = fun row -> let cpu_time = ref 0L in for di = 0 to Array.length row-1 do - let t, _, _ = row.(di) in + let t = row.(di) in cpu_time := !cpu_time +^ t done; Int64.to_float !cpu_time @@ -938,7 +922,7 @@ let redraw = let dom_names = String.concat "" ( List.map ( - fun (_, name, _, _, _, _, _) -> + fun (_, name, _, _, _, _, _, _) -> let len = String.length name in let width = max (len+1) 7 in pad width name @@ -957,8 +941,8 @@ let redraw = addch ' '; List.iteri ( - fun di (domid, name, _, _, _, _, _) -> - let t, is_average, is_running = pcpus.(p).(di) in + fun di (domid, name, _, _, _, _, _, _) -> + let t = pcpus.(p).(di) in let len = String.length name in let width = max (len+1) 7 in let str = @@ -966,9 +950,7 @@ let redraw = else ( let t = Int64.to_float t in let percent = 100. *. t /. total_cpu_per_pcpu in - sprintf "%s%c%c " (Show.percent percent) - (if is_average then '=' else ' ') - (if is_running then '#' else ' ') + sprintf "%s " (Show.percent percent) ) in addstr (pad width str); ()