Use more subprocesses

lib/check-signature.js

@@ -1,8 +1,13 @@
 const Nacl = require('tweetnacl/nacl-fast');
 
+// XXX npm "os" and "child_process"
+
 // TODO if this process is using too much CPU, we can use "cluster" to add load balancing to this code
 
+console.log('New child process', process.pid);
+
 process.on('message', function (data) {
+    console.log('In process', process.pid)
     console.log(+new Date(), "Message received by subprocess");
     if (!data || !data.key || !data.msg || !data.txid) {
         process.send({

lib/hk-util.js

@@ -7,6 +7,7 @@ const Util = require("./common-util");
 const MetaRPC = require("./commands/metadata");
 const Nacl = require('tweetnacl/nacl-fast');
 const { fork } = require('child_process');
+const numCPUs = require('os').cpus().length;
 
 const now = function () { return (new Date()).getTime(); };
 const ONE_DAY = 1000 * 60 * 60 * 24; // one day in milliseconds
@@ -922,11 +923,32 @@ HK.onDirectMessage = function (Env, Server, seq, userId, json) {
     * adds timestamps to incoming messages
     * writes messages to the store
 */
-const check = fork('lib/check-signature.js');
+
+
 const onChecked = Util.mkEvent();
-check.on('message', function (res) {
-    onChecked.fire(res);
-});
+// Create our workers
+const workers = [];
+for (let i = 0; i < numCPUs; i++) {
+    workers.push(fork('lib/check-signature.js'));
+}
+var initWorker = function (worker) {
+    worker.on('message', function (res) {
+        onChecked.fire(res);
+    });
+    // Spawn a new process in one ends
+    worker.on('exit', function () {
+        // XXX make sure it's dead?
+        var idx = workers.indexOf(worker);
+        if (idx !== -1) {
+            workers.splice(idx, 1);
+        }
+        // Spawn a new one
+        var w = fork('lib/check-signature.js');
+        workers.push(w);
+        initWorker(w);
+    });
+};
+workers.forEach(initWorker);
 
 HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
     console.log(+new Date(), "onChannelMessage");
@@ -996,7 +1018,8 @@ HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
 
         console.log(+new Date(), "Send verification request");
         // Send the request
-        check.send({
+        const random = Math.floor(Math.random() * 4);
+        workers[random].send({
             txid: txid,
             msg: signedMsg,
             key: metadata.validateKey