Stop containers in parallel fashion

Prior, we were stopping containers serially.  So if a container had a default
timeout of 10 seconds and there were five containers being stopped, the operation
would take roughly 50 seconds.  If we stop these containers in parallel, the operation
should be roughly 10 seconds and change which is a significant speed up at scale.

Signed-off-by: baude <bbaude@redhat.com>

1 files changed, 20 insertions, 7 deletions

diff --git a/cmd/podman/stop.go b/cmd/podman/stop.go
index d2fa87730..664d91ea3 100644
--- a/cmd/podman/stop.go
+++ b/cmd/podman/stop.go
@@ -3,6 +3,7 @@ package main
 import (
 	"fmt"
 	"os"
+	rt "runtime"
 
 	"github.com/containers/libpod/cmd/podman/libpodruntime"
 	"github.com/containers/libpod/libpod"
@@ -98,21 +99,33 @@ func stopCmd(c *cli.Context) error {
 		}
 	}
 
+	var stopFuncs []workerInput
 	for _, ctr := range containers {
+		con := ctr
 		var stopTimeout uint
 		if c.IsSet("timeout") {
 			stopTimeout = c.Uint("timeout")
 		} else {
 			stopTimeout = ctr.StopTimeout()
 		}
-		if err := ctr.StopWithTimeout(stopTimeout); err != nil && err != libpod.ErrCtrStopped {
-			if lastError != nil {
-				fmt.Fprintln(os.Stderr, lastError)
-			}
-			lastError = errors.Wrapf(err, "failed to stop container %v", ctr.ID())
-		} else {
-			fmt.Println(ctr.ID())
+		f := func() error {
+			return con.StopWithTimeout(stopTimeout)
+		}
+		stopFuncs = append(stopFuncs, workerInput{
+			containerID:  con.ID(),
+			parallelFunc: f,
+		})
+	}
+
+	stopErrors := parallelExecuteWorkerPool(rt.NumCPU()*3, stopFuncs)
+
+	for cid, result := range stopErrors {
+		if result != nil && result != libpod.ErrCtrStopped {
+			fmt.Println(result.Error())
+			lastError = result
+			continue
 		}
+		fmt.Println(cid)
 	}
 	return lastError
 }