diff --git a/app/daemon.go b/app/daemon.go
index 31c9e6c..1bb1ab5 100644
--- a/app/daemon.go
+++ b/app/daemon.go
@@ -94,26 +94,52 @@ func (f *Filter) sendActions(match string, at time.Time) {
 }
 
 func (a *Action) exec(match string) {
-	wgActions.Add(1)
-	go func() {
-		defer wgActions.Done()
+	defer wgActions.Done()
 
-		computedCommand := make([]string, 0, len(a.Cmd))
-		for _, item := range a.Cmd {
-			computedCommand = append(computedCommand, strings.ReplaceAll(item, a.filter.pattern.nameWithBraces, match))
-		}
+	computedCommand := make([]string, 0, len(a.Cmd))
+	for _, item := range a.Cmd {
+		computedCommand = append(computedCommand, strings.ReplaceAll(item, a.filter.pattern.nameWithBraces, match))
+	}
 
-		logger.Printf(logger.INFO, "%s.%s.%s: run %s\n", a.filter.stream.name, a.filter.name, a.name, computedCommand)
+	logger.Printf(logger.INFO, "%s.%s.%s: run %s\n", a.filter.stream.name, a.filter.name, a.name, computedCommand)
 
-		cmd := exec.Command(computedCommand[0], computedCommand[1:]...)
+	cmd := exec.Command(computedCommand[0], computedCommand[1:]...)
 
-		if ret := cmd.Run(); ret != nil {
-			logger.Printf(logger.ERROR, "%s.%s.%s: run %s, code %s\n", a.filter.stream.name, a.filter.name, a.name, computedCommand, ret)
-		}
-	}()
+	if ret := cmd.Run(); ret != nil {
+		logger.Printf(logger.ERROR, "%s.%s.%s: run %s, code %s\n", a.filter.stream.name, a.filter.name, a.name, computedCommand, ret)
+	}
 }
 
-func ActionsManager() {
+func ActionsManager(concurrency int) {
+	// concurrency init
+	execActionsC := make(chan PA)
+	if concurrency > 0 {
+		for i := 0; i < concurrency; i++ {
+			go func() {
+				var pa PA
+				for {
+					pa = <-execActionsC
+					pa.a.exec(pa.p)
+				}
+			}()
+		}
+	} else {
+		go func() {
+			var pa PA
+			for {
+				pa = <-execActionsC
+				go func(pa PA) {
+					pa.a.exec(pa.p)
+				}(pa)
+			}
+		}()
+	}
+	execAction := func(a *Action, p string) {
+		wgActions.Add(1)
+		execActionsC <- PA{p, a}
+	}
+
+	// main
 	pendingActionsC := make(chan PAT)
 	for {
 		select {
@@ -123,13 +149,13 @@ func ActionsManager() {
 			now := time.Now()
 			// check if must be executed now
 			if then.Compare(now) <= 0 {
-				action.exec(pattern)
+				execAction(action, pattern)
 			} else {
 				actionsLock.Lock()
 				if actions[pa] == nil {
 					actions[pa] = make(map[time.Time]struct{})
 				}
-				actions[PA{pattern, action}][then] = struct{}{}
+				actions[pa][then] = struct{}{}
 				actionsLock.Unlock()
 				go func(insidePat PAT, insideNow time.Time) {
 					time.Sleep(insidePat.t.Sub(insideNow))
@@ -141,20 +167,17 @@ func ActionsManager() {
 			pattern, action, then := pat.p, pat.a, pat.t
 			actionsLock.Lock()
 			if actions[pa] != nil {
-				if _, ok := actions[pa][then]; ok {
-					delete(actions[pa], then)
-					action.exec(pattern)
-				}
+				delete(actions[pa], then)
 			}
 			actionsLock.Unlock()
-			action.exec(pattern)
+			execAction(action, pattern)
 		case fo := <-flushToActionsC:
 			ret := make(ActionsMap)
 			actionsLock.Lock()
 			for pa := range actions {
 				if pa.p == fo.p {
 					for range actions[pa] {
-						pa.a.exec(pa.p)
+						execAction(pa.a, pa.p)
 					}
 					ret[pa] = actions[pa]
 					delete(actions, pa)
@@ -164,9 +187,11 @@ func ActionsManager() {
 			fo.ret <- ret
 		case _, _ = <-stopActions:
 			actionsLock.Lock()
-			for pat := range actions {
-				if pat.a.OnExit {
-					pat.a.exec(pat.p)
+			for pa := range actions {
+				if pa.a.OnExit {
+					for range actions[pa] {
+						execAction(pa.a, pa.p)
+					}
 				}
 			}
 			actionsLock.Unlock()
@@ -349,7 +374,7 @@ func Daemon(confFilename string) {
 
 	go DatabaseManager(conf)
 	go MatchesManager()
-	go ActionsManager()
+	go ActionsManager(conf.Concurrency)
 
 	// Ready to start
 
diff --git a/app/example.yml b/app/example.yml
index 45264e1..e275e5a 100644
--- a/app/example.yml
+++ b/app/example.yml
@@ -8,6 +8,11 @@ definitions:
 # ip46tables is a minimal C program (only POSIX dependencies) present as a subdirectory.
 # it permits to handle both ipv4/iptables and ipv6/ip6tables commands
 
+# if set to a positive number → max number of concurrent actions
+# if set to a negative number → no limit
+# if not specified or set to 0 → defaults to the number of CPUs on the system
+concurrency: 0
+
 # patterns are substitued in regexes.
 # when a filter performs an action, it replaces the found pattern
 patterns:
diff --git a/app/startup.go b/app/startup.go
index 54d9097..1364d8b 100644
--- a/app/startup.go
+++ b/app/startup.go
@@ -6,6 +6,7 @@ import (
 	"log"
 	"os"
 	"regexp"
+	"runtime"
 	"strings"
 	"time"
 
@@ -15,6 +16,9 @@ import (
 )
 
 func (c *Conf) setup() {
+	if c.Concurrency == 0 {
+		c.Concurrency = runtime.NumCPU()
+	}
 
 	for patternName := range c.Patterns {
 		pattern := c.Patterns[patternName]
@@ -144,13 +148,11 @@ func parseConf(filename string) *Conf {
 
 	var conf Conf
 	if filename[len(filename)-4:] == ".yml" || filename[len(filename)-5:] == ".yaml" {
-		logger.Println(logger.DEBUG, "yaml")
 		err = jsonnet.NewYAMLToJSONDecoder(data).Decode(&conf)
 		if err != nil {
 			logger.Fatalln("Failed to parse yaml configuration file:", err)
 		}
 	} else {
-		logger.Println(logger.DEBUG, "json")
 		var jsondata string
 		jsondata, err = jsonnet.MakeVM().EvaluateFile(filename)
 		if err == nil {
diff --git a/app/types.go b/app/types.go
index 0825878..dd8b72a 100644
--- a/app/types.go
+++ b/app/types.go
@@ -8,10 +8,11 @@ import (
 )
 
 type Conf struct {
-	Patterns map[string]*Pattern `json:"patterns"`
-	Streams  map[string]*Stream  `json:"streams"`
-	Start    [][]string          `json:"start"`
-	Stop     [][]string          `json:"stop"`
+	Concurrency int                 `json:"concurrency"`
+	Patterns    map[string]*Pattern `json:"patterns"`
+	Streams     map[string]*Stream  `json:"streams"`
+	Start       [][]string          `json:"start"`
+	Stop        [][]string          `json:"stop"`
 }
 
 type Pattern struct {
diff --git a/config/example.jsonnet b/config/example.jsonnet
index 8a693cc..add9588 100644
--- a/config/example.jsonnet
+++ b/config/example.jsonnet
@@ -21,6 +21,11 @@ local iptables(args) = ['ip46tables', '-w'] + args;
     },
   },
 
+  // if set to a positive number → max number of concurrent actions
+  // if set to a negative number → no limit
+  // if not specified or set to 0 → defaults to the number of CPUs on the system
+  concurrency: 0,
+
   // Those commands will be executed in order at start, before everything else
   start: [
     // Create an iptables chain for reaction
diff --git a/config/heavy-load.yml b/config/heavy-load.yml
index a63999a..1c149c3 100644
--- a/config/heavy-load.yml
+++ b/config/heavy-load.yml
@@ -7,6 +7,8 @@ patterns:
     ignore:
       - 1.0.0.1
 
+concurrency: 0
+
 streams:
   tailDown1:
     cmd: [ 'sh', '-c', 'sleep 2; seq 100010 | while read i; do echo found $(($i % 100)); done' ]
@@ -18,9 +20,9 @@ streams:
         retryperiod: 1m
         actions:
           damn:
-            cmd: [ 'echo', '<num>' ]
+            cmd: [ 'sleep', '0.<num>' ]
           undamn:
-            cmd: [ 'echo', 'undamn', '<num>' ]
+            cmd: [ 'sleep', '0.<num>' ]
             after: 1m
             onexit: false
   tailDown2:
@@ -33,9 +35,9 @@ streams:
         retryperiod: 1m
         actions:
           damn:
-            cmd: [ 'echo', '<num>' ]
+            cmd: [ 'sleep', '0.<num>' ]
           undamn:
-            cmd: [ 'echo', 'undamn', '<num>' ]
+            cmd: [ 'sleep', '0.<num>' ]
             after: 1m
             onexit: false
   tailDown3:
@@ -48,9 +50,9 @@ streams:
         retryperiod: 2m
         actions:
           damn:
-            cmd: [ 'true' ]
+            cmd: [ 'sleep', '0.<num>' ]
           undamn:
-            cmd: [ 'true' ]
+            cmd: [ 'sleep', '0.<num>' ]
             after: 1m
             onexit: false
   tailDown4:
@@ -63,8 +65,8 @@ streams:
         retryperiod: 2m
         actions:
           damn:
-            cmd: [ 'echo', '<num>' ]
+            cmd: [ 'sleep', '0.<num>' ]
           undamn:
-            cmd: [ 'echo', 'undamn', '<num>' ]
+            cmd: [ 'sleep', '0.<num>' ]
             after: 1m
             onexit: false
diff --git a/config/test.jsonnet b/config/test.jsonnet
index b5fc18e..63f6b96 100644
--- a/config/test.jsonnet
+++ b/config/test.jsonnet
@@ -18,12 +18,12 @@
 
   streams: {
     tailDown1: {
-      cmd: ['sh', '-c', "echo 1 2 3 4 5 | tr ' ' '\n' | while read i; do sleep 2; echo found $(($i % 10)); done"],
+      cmd: ['sh', '-c', "echo 1 2 3 4 5 5 | tr ' ' '\n' | while read i; do sleep 1; echo found $(($i % 10)); done"],
       // cmd: ['sh', '-c', "echo 1 2 3 4 5 1 2 3 4 5 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 | tr ' ' '\n' | while read i; do sleep 2; echo found $(($i % 10)); done"],
       filters: {
         findIP: {
           regex: ['^found <num>$'],
-          retry: 3,
+          retry: 1,
           retryperiod: '30s',
           actions: {
             damn: {
@@ -31,7 +31,7 @@
             },
             undamn: {
               cmd: ['echo', 'undamn', '<num>'],
-              after: '30s',
+              after: '4s',
               onexit: true,
             },
           },