Added optional container restore statistics

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

 # podman container restore --latest --print-stats
 {
     "podman_restore_duration": 305871,
     "container_statistics": [
         {
             "Id": "47b02e1d474b5d5fe917825e91ac653efa757c91e5a81a368d771a78f6b5ed20",
             "runtime_restore_duration": 140614,
             "criu_statistics": {
                 "forking_time": 5,
                 "restore_time": 67672,
                 "pages_restored": 14
             }
         }
     ]
 }

The output contains 'podman_restore_duration' which contains the
number of microseconds Podman required to restore the checkpoint. The
output also includes 'runtime_restore_duration' which is the time
the runtime needed to restore 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>

1 files changed, 4 insertions, 1 deletions

diff --git a/libpod/oci.go b/libpod/oci.go
index f78600210..f45c1a105 100644
--- a/libpod/oci.go
+++ b/libpod/oci.go
@@ -23,7 +23,10 @@ type OCIRuntime interface {
 	Path() string
 
 	// CreateContainer creates the container in the OCI runtime.
-	CreateContainer(ctr *Container, restoreOptions *ContainerCheckpointOptions) error
+	// The returned int64 contains the microseconds needed to restore
+	// the given container if it is a restore and if restoreOptions.PrintStats
+	// is true. In all other cases the returned int64 is 0.
+	CreateContainer(ctr *Container, restoreOptions *ContainerCheckpointOptions) (int64, error)
 	// UpdateContainerStatus updates the status of the given container.
 	UpdateContainerStatus(ctr *Container) error
 	// StartContainer starts the given container.