diff --git a/Makefile b/Makefile
index 887b285454..3128cfa78c 100644
--- a/Makefile
+++ b/Makefile
@@ -313,6 +313,10 @@ dist-upload: $(TARBALL) $(PKG)
 	scp $(TARBALL) node@nodejs.org:~/web/nodejs.org/dist/$(VERSION)/$(TARBALL)
 	scp $(PKG) node@nodejs.org:~/web/nodejs.org/dist/$(VERSION)/$(TARNAME).pkg
 
+wrkclean:
+	$(MAKE) -C tools/wrk/ clean
+	rm tools/wrk/wrk
+
 wrk: tools/wrk/wrk
 tools/wrk/wrk:
 	$(MAKE) -C tools/wrk/
@@ -323,7 +327,7 @@ bench-net: all
 bench-tls: all
 	@$(NODE) benchmark/common.js tls
 
-bench-http: all
+bench-http: wrk all
 	@$(NODE) benchmark/common.js http
 
 bench-fs: all
diff --git a/benchmark/common.js b/benchmark/common.js
index 289f17d128..3c478bd019 100644
--- a/benchmark/common.js
+++ b/benchmark/common.js
@@ -11,7 +11,6 @@ if (module === require.main) {
     process.exit(1);
   }
 
-  var path = require('path');
   var fs = require('fs');
   var dir = path.join(__dirname, type);
   var tests = fs.readdirSync(dir);
@@ -59,16 +58,18 @@ function Benchmark(fn, options) {
   });
 }
 
-// run ab against a server.
-Benchmark.prototype.ab = function(path, args, cb) {
-  var url = 'http://127.0.0.1:' + exports.PORT + path;
-  args.push(url);
-
+// benchmark an http server.
+Benchmark.prototype.http = function(p, args, cb) {
   var self = this;
-  var out = '';
+  var wrk = path.resolve(__dirname, '..', 'tools', 'wrk', 'wrk');
+  var regexp = /Requests\/sec:[ \t]+([0-9\.]+)/;
   var spawn = require('child_process').spawn;
-  // console.error('ab %s', args.join(' '));
-  var child = spawn('ab', args);
+  var url = 'http://127.0.0.1:' + exports.PORT + p;
+
+  args = args.concat(url);
+
+  var out = '';
+  var child = spawn(wrk, args);
 
   child.stdout.setEncoding('utf8');
 
@@ -81,14 +82,14 @@ Benchmark.prototype.ab = function(path, args, cb) {
       cb(code);
 
     if (code) {
-      console.error('ab failed with ' + code);
+      console.error('wrk failed with ' + code);
       process.exit(code)
     }
-    var m = out.match(/Requests per second: +([0-9\.]+)/);
+    var m = out.match(regexp);
     var qps = m && +m[1];
     if (!qps) {
-      process.stderr.write(out + '\n');
-      console.error('ab produced strange output');
+      console.error('%j', out);
+      console.error('wrk produced strange output');
       process.exit(1);
     }
     self.report(+qps);
diff --git a/benchmark/http/cluster.js b/benchmark/http/cluster.js
index a8c7abe689..12bb8d5946 100644
--- a/benchmark/http/cluster.js
+++ b/benchmark/http/cluster.js
@@ -7,7 +7,7 @@ if (cluster.isMaster) {
     // unicode confuses ab on os x.
     type: ['bytes', 'buffer'],
     length: [4, 1024, 102400],
-    c: [50, 150]
+    c: [50, 500]
   });
 } else {
   require('../http_simple.js');
@@ -27,11 +27,12 @@ function main(conf) {
     setTimeout(function() {
       var path = '/' + conf.type + '/' + conf.length;
       var args = ['-r', '-t', 5, '-c', conf.c, '-k'];
+      var args = ['-r', 5000, '-t', 8, '-c', conf.c];
 
-      bench.ab(path, args, function() {
+      bench.http(path, args, function() {
         w1.destroy();
         w2.destroy();
       });
-    }, 2000);
+    }, 100);
   });
 }
diff --git a/benchmark/http/http_simple.js b/benchmark/http/http_simple.js
index 2cef41f46f..04a2a2911f 100644
--- a/benchmark/http/http_simple.js
+++ b/benchmark/http/http_simple.js
@@ -5,7 +5,7 @@ var bench = common.createBenchmark(main, {
   // unicode confuses ab on os x.
   type: ['bytes', 'buffer'],
   length: [4, 1024, 102400],
-  c: [50, 150]
+  c: [50, 500]
 });
 
 function main(conf) {
@@ -15,14 +15,9 @@ function main(conf) {
   var server = spawn(process.execPath, [simple]);
   setTimeout(function() {
     var path = '/' + conf.type + '/' + conf.length; //+ '/' + conf.chunks;
-    var args = ['-r', '-t', 5];
+    var args = ['-r', 5000, '-t', 8, '-c', conf.c];
 
-    if (+conf.c !== 1)
-      args.push('-c', conf.c);
-
-    args.push('-k');
-
-    bench.ab(path, args, function() {
+    bench.http(path, args, function() {
       server.kill();
     });
   }, 2000);