Added optional container checkpointing statistics

This adds the parameter '--print-stats' to 'podman container checkpoint'.
With '--print-stats' Podman will measure how long Podman itself, the OCI
runtime and CRIU requires to create a checkpoint and print out these
information. CRIU already creates checkpointing statistics which are
just read in addition to the added measurements. In contrast to just
printing out the ID of the checkpointed container, Podman will now print
out JSON:

 # podman container checkpoint --latest --print-stats
 {
     "podman_checkpoint_duration": 360749,
     "container_statistics": [
         {
             "Id": "25244244bf2efbef30fb6857ddea8cb2e5489f07eb6659e20dda117f0c466808",
             "runtime_checkpoint_duration": 177222,
             "criu_statistics": {
                 "freezing_time": 100657,
                 "frozen_time": 60700,
                 "memdump_time": 8162,
                 "memwrite_time": 4224,
                 "pages_scanned": 20561,
                 "pages_written": 2129
             }
         }
     ]
 }

The output contains 'podman_checkpoint_duration' which contains the
number of microseconds Podman required to create the checkpoint. The
output also includes 'runtime_checkpoint_duration' which is the time
the runtime needed to checkpoint that specific container. Each container
also includes 'criu_statistics' which displays the timing information
collected by CRIU.

Signed-off-by: Adrian Reber <areber@redhat.com>

2 files changed, 16 insertions, 2 deletions

diff --git a/pkg/api/handlers/libpod/containers.go b/pkg/api/handlers/libpod/containers.go
index 343c0d0b3..d8312e9be 100644
--- a/pkg/api/handlers/libpod/containers.go
+++ b/pkg/api/handlers/libpod/containers.go
@@ -214,6 +214,7 @@ func Checkpoint(w http.ResponseWriter, r *http.Request) {
 		TCPEstablished bool `schema:"tcpEstablished"`
 		Export         bool `schema:"export"`
 		IgnoreRootFS   bool `schema:"ignoreRootFS"`
+		PrintStats     bool `schema:"printStats"`
 	}{
 		// override any golang type defaults
 	}
@@ -248,11 +249,12 @@ func Checkpoint(w http.ResponseWriter, r *http.Request) {
 		KeepRunning:    query.LeaveRunning,
 		TCPEstablished: query.TCPEstablished,
 		IgnoreRootfs:   query.IgnoreRootFS,
+		PrintStats:     query.PrintStats,
 	}
 	if query.Export {
 		options.TargetFile = targetFile
 	}
-	err = ctr.Checkpoint(r.Context(), options)
+	criuStatistics, runtimeCheckpointDuration, err := ctr.Checkpoint(r.Context(), options)
 	if err != nil {
 		utils.InternalServerError(w, err)
 		return
@@ -267,7 +269,15 @@ func Checkpoint(w http.ResponseWriter, r *http.Request) {
 		utils.WriteResponse(w, http.StatusOK, f)
 		return
 	}
-	utils.WriteResponse(w, http.StatusOK, entities.CheckpointReport{Id: ctr.ID()})
+	utils.WriteResponse(
+		w,
+		http.StatusOK,
+		entities.CheckpointReport{
+			Id:              ctr.ID(),
+			RuntimeDuration: runtimeCheckpointDuration,
+			CRIUStatistics:  criuStatistics,
+		},
+	)
 }
 
 func Restore(w http.ResponseWriter, r *http.Request) {
diff --git a/pkg/api/server/register_containers.go b/pkg/api/server/register_containers.go
index c4919182b..e98098f97 100644
--- a/pkg/api/server/register_containers.go
+++ b/pkg/api/server/register_containers.go
@@ -1441,6 +1441,10 @@ func (s *APIServer) registerContainersHandlers(r *mux.Router) error {
 	//    name: ignoreRootFS
 	//    type: boolean
 	//    description: do not include root file-system changes when exporting
+	//  - in: query
+	//    name: printStats
+	//    type: boolean
+	//    description: add checkpoint statistics to the returned CheckpointReport
 	// produces:
 	// - application/json
 	// responses: