client_latency.js

// first start node http_simple.js
var http = require('http');

var latency = [];

var numRequests = parseInt(process.argv[2], 10) || 100;
var maxSockets = parseInt(process.argv[3], 10) || 100;
var runs = parseInt(process.argv[4], 10) || 100;
var r = 0;

var port = parseInt(process.env.PORT, 10) || 8000;
var host = 'localhost';

http.globalAgent.maxSockets = maxSockets;

run();

function run() {
  if (r++ === runs) {
    return finish();
  }

  // make numRequests in parallel
  // retain the order in which they are *made*.  This requires trapping
  // each one in a closure, since otherwise, we'll of course end
  // up mostly sorting them in ascending order, since the cb from a
  // fast request will almost always be called before the cb from a
  // slow one.
  var c = numRequests;
  var lat = [];
  latency.push(lat);
  for (var i = 0; i < numRequests; i++) (function (i) {
    request(function(l) {
      lat[i] = l;
      c--;
      if (c === 0) run();
    });
  })(i);
}

function request(cb) {
  var opts = { host: host,
               port: port,
               path: '/bytes/12' };
  var start = Date.now();
  var req = http.get(opts, function(res) {
    return cb(Date.now() - start);
  });
}

function finish() {
  var data = [];
  latency.forEach(function(run, i) {
    run.forEach(function(l, j) {
      data[j] = data[j] || [];
      data[j][i] = l;
    });
  });

  data = data.map(function (l, i) {
    return l.join('\t')
  }).join('\n') + '\n';

  var fname = 'client_latency_'+numRequests+'_'+maxSockets+'_'+runs+'.tab'
  require('fs').writeFile(fname, data, function(er) {
    if (er) throw er;
    console.log('written: %s', fname);
  });
}

fast_client_latency_50_50_10.tab

21	7	12	8	11	15	6	6	5	6
12	6	12	8	13	15	10	6	4	6
12	6	12	8	13	15	10	6	4	6
11	6	12	8	12	15	10	7	4	6
11	6	12	8	12	15	10	7	5	7
11	7	11	8	12	15	10	7	4	7
11	7	11	9	12	15	10	7	5	7
11	7	14	9	12	16	10	7	5	7
11	6	12	6	12	15	10	7	5	7
11	6	8	6	10	15	9	7	4	5
10	6	8	6	10	15	9	7	4	5
10	6	8	7	10	15	9	6	5	5
10	7	10	7	10	15	9	6	6	5
10	7	8	7	10	5	8	8	5	5
10	4	7	6	12	5	8	8	6	6
8	5	7	6	12	5	7	8	6	6
10	5	7	5	12	5	7	8	6	6
20	5	7	5	12	10	7	7	6	5
19	7	7	5	12	5	7	4	6	5
19	8	6	6	12	14	7	5	6	6
19	8	6	8	12	14	10	7	6	6
19	8	5	8	12	14	10	7	6	6
19	8	5	8	12	14	10	8	5	6
18	8	6	9	12	13	10	8	7	6
18	8	5	9	12	14	12	8	7	7
18	9	5	9	11	13	11	8	7	7
18	8	5	8	11	13	11	8	7	7
18	12	10	8	11	13	12	8	8	7
12	12	14	9	12	13	12	8	8	8
12	11	14	9	12	12	11	9	8	8
12	9	13	9	11	12	11	9	8	8
12	11	13	9	8	12	11	9	9	8
20	11	13	10	8	12	11	9	12	8
21	11	13	10	8	12	11	9	9	9
21	11	13	10	8	11	11	10	12	9
21	13	13	10	8	12	10	10	13	9
20	13	15	10	8	11	10	11	13	10
20	13	16	10	8	11	10	11	13	10
20	12	15	10	9	11	10	12	13	10
20	11	15	10	9	11	10	12	14	9
20	12	15	11	9	11	11	12	13	12
20	11	15	11	7	11	11	12	14	10
20	12	16	11	10	11	11	11	13	10
19	13	15	10	10	11	11	11	13	10
21	12	15	11	11	11	12	11	12	11
21	12	15	12	10	11	12	11	12	15
21	12	15	12	10	10	12	12	12	11
21	13	14	11	10	10	12	12	12	11
20	13	14	12	10	10	11	3	12	11
20	3	3	4	4	4	3	12	2	3

fast_client_latency_50_5_10.tab

17	7	2	3	3	4	2	1	4	2
8	6	2	3	3	2	2	1	2	2
10	5	1	2	2	2	2	1	4	2
10	6	1	2	2	4	2	1	4	1
7	5	1	1	2	1	1	2	2	1
9	6	2	2	3	2	2	2	2	1
9	6	3	2	2	3	2	2	4	1
9	6	3	2	2	3	2	3	4	2
10	6	3	3	2	3	2	3	4	2
10	7	3	3	3	3	2	3	4	2
10	7	3	3	3	3	2	3	3	2
10	7	3	3	3	3	2	3	4	2
10	7	4	3	3	3	2	3	4	2
10	7	4	3	4	3	2	3	4	2
10	7	4	3	3	3	3	3	4	2
11	7	4	3	4	3	3	4	4	2
11	7	4	3	4	4	3	4	4	2
11	5	4	3	4	4	3	4	4	2
11	3	4	3	4	4	3	4	4	3
11	4	4	4	5	4	3	4	4	3
11	4	4	4	5	5	3	4	4	3
11	4	4	4	5	5	3	4	4	3
11	5	4	4	5	5	3	4	4	3
11	5	4	4	5	5	2	4	5	3
12	5	4	4	5	5	3	5	5	3
12	5	5	4	5	5	3	5	5	3
12	5	5	5	5	5	3	5	5	3
12	5	5	4	5	5	3	5	5	3
12	5	5	5	5	6	3	5	5	3
12	5	5	5	6	5	3	5	5	4
11	5	5	5	6	6	3	5	5	5
11	5	5	5	6	6	3	5	5	5
12	6	5	5	6	6	3	5	5	5
12	6	5	5	6	6	3	5	5	5
13	6	4	5	6	6	4	5	6	5
13	6	4	5	6	6	3	5	6	5
13	6	4	5	7	6	4	6	6	5
13	6	4	4	6	6	4	5	6	5
13	6	5	5	6	6	4	5	6	5
13	6	5	5	6	6	4	6	6	5
14	6	5	5	7	6	4	6	6	6
14	6	5	5	8	6	4	6	6	6
13	6	5	5	8	7	4	6	6	6
14	6	5	5	8	7	4	7	6	6
14	6	5	5	8	7	4	7	6	6
14	7	5	5	8	7	4	7	7	6
14	7	5	6	8	7	4	7	6	6
14	7	5	6	8	7	5	7	7	6
14	7	5	6	8	7	4	7	6	6
14	7	5	6	8	7	5	7	7	6

http_server_lag.js

var http = require('http');
var port = parseInt(process.env.PORT, 10) || 8000;
var lag = parseInt(process.argv[2], 10) || 100;

http.createServer(function(req, res) {
  res.writeHead(200, { 'content-type': 'text/plain',
                       'content-lengt': '2' });
  setTimeout(function() {
    res.end('ok');
  }, lag);
}).listen(port, 'localhost');

slow_client_latency_50_50_10.tab

117	112	108	107	110	108	108	106	105	104
110	109	108	104	110	108	105	106	105	104
109	111	108	104	110	108	105	106	105	104
109	110	108	105	108	108	106	106	105	104
109	110	108	105	110	108	106	105	105	104
109	110	109	105	108	107	106	106	104	104
110	110	109	105	108	107	105	105	104	103
110	110	108	105	110	106	105	105	106	103
109	110	106	105	111	109	105	105	104	103
109	109	106	105	110	109	105	105	104	103
108	109	106	105	110	108	106	104	104	103
110	109	106	105	110	107	106	105	105	103
110	109	106	104	111	107	106	105	105	104
110	112	106	104	111	107	105	104	105	104
110	112	106	104	111	107	105	104	105	104
109	112	106	104	109	107	104	104	104	104
113	111	106	104	109	107	104	104	104	105
113	111	106	104	109	107	104	104	104	105
113	111	107	104	109	106	104	104	104	105
113	111	107	105	109	106	105	104	105	105
114	111	105	107	109	106	105	104	106	106
114	111	105	107	109	106	105	104	106	106
114	111	103	107	109	106	105	104	106	104
108	109	103	106	108	109	106	106	106	104
107	109	104	105	108	108	107	105	106	105
107	109	104	105	108	109	106	105	106	104
115	104	104	105	107	109	106	105	105	105
115	109	106	105	107	109	106	106	105	104
115	108	106	106	109	108	106	106	109	107
115	108	106	106	109	108	106	105	108	107
115	108	106	106	107	107	106	105	109	107
115	108	106	106	108	107	106	105	109	106
114	108	109	105	107	107	108	109	109	107
114	107	109	105	107	103	106	107	109	107
114	107	109	103	107	107	106	108	109	107
114	107	109	106	107	107	108	108	109	106
114	107	109	105	110	107	108	107	108	109
114	107	109	107	109	108	108	107	108	108
113	107	109	108	110	107	109	107	108	107
113	111	108	108	110	107	109	107	110	107
114	111	109	108	110	108	109	107	109	102
113	111	109	107	110	108	109	107	109	108
113	109	109	108	110	108	108	107	110	109
113	109	109	107	110	108	108	107	110	108
113	109	108	107	108	108	110	108	109	108
113	110	109	109	108	109	108	108	109	109
113	110	108	109	106	109	108	108	109	109
113	110	102	108	102	109	108	108	109	109
113	110	108	109	106	109	109	109	109	109
112	110	107	109	106	109	103	102	103	109

slow_client_latency_50_5_10.tab

111	106	104	102	103	102	102	102	102	103
105	106	102	102	101	102	102	102	102	103
105	106	102	102	102	102	102	102	102	103
104	106	103	102	102	102	102	102	102	102
103	106	103	102	102	102	102	102	102	102
204	207	204	203	202	203	203	203	203	202
204	207	204	203	202	203	204	203	203	203
204	207	204	203	202	203	204	204	203	203
204	207	204	203	202	203	204	204	203	203
204	206	204	203	202	203	204	204	203	203
305	307	305	305	303	305	305	305	304	303
307	308	305	304	304	305	305	305	305	303
307	308	305	304	304	305	305	305	305	303
307	308	305	304	304	305	305	304	305	303
307	308	305	304	304	305	305	304	304	303
406	408	406	404	404	405	405	405	405	404
406	408	406	404	405	405	406	405	406	404
406	408	406	404	405	405	406	405	406	404
406	408	406	404	405	405	406	405	405	404
406	405	406	404	405	405	406	405	406	404
507	507	507	505	505	506	506	506	507	505
508	507	507	505	505	507	507	507	507	505
507	508	507	505	505	507	506	506	507	505
508	508	507	505	505	507	506	506	507	505
507	508	507	505	505	507	506	506	507	505
609	609	609	606	606	608	608	608	608	606
609	609	609	606	607	608	608	608	609	606
609	609	608	606	607	608	608	608	609	606
609	609	608	606	607	608	608	608	608	606
609	609	609	606	607	608	608	608	608	606
710	710	709	708	709	709	709	709	709	706
710	710	709	708	709	709	709	709	710	707
710	710	709	708	709	709	709	709	709	707
710	710	709	708	709	709	709	709	709	707
710	710	709	708	709	709	709	709	709	707
811	811	811	809	810	810	811	810	809	807
811	812	811	810	811	810	812	810	810	807
811	812	811	810	810	810	812	810	810	807
811	812	811	809	810	810	812	810	810	807
811	812	811	809	810	810	811	810	810	807
912	912	912	911	912	910	912	910	911	908
913	912	912	911	912	911	912	911	911	908
913	912	912	911	912	911	912	911	911	908
912	912	912	911	912	911	912	910	911	908
913	912	912	911	912	911	912	911	911	908
1014	1014	1013	1012	1013	1012	1013	1012	1012	1009
1014	1014	1013	1012	1013	1012	1013	1012	1012	1009
1014	1014	1013	1012	1014	1012	1013	1012	1012	1009
1014	1014	1013	1012	1013	1012	1013	1012	1012	1009
1014	1014	1013	1012	1013	1012	1013	1012	1012	1009

In each of these, a column is a single run, and each row is a request's latency.

The numbers in the filename indicate the number of requests per run, the maximum number of sockets, and the number of runs to perform. Note that the values jump around more or less randomly when the maxSockets and numRequests are equal, but stack up in a stepwise fashion when maxSockets is much lower than numRequests.