[编辑：我在代码中添加了一些分析日志和进程退出跟踪，并将结果粘贴在帖子末尾]
在使用端口共享时，我无法让 Nodejs 集群正确利用服务器的可用 CPU。该问题在两个不同的服务器（个人计算机和远程 VPS）上观察到，如下所示，并且已被评论者复制（参见 jfriend00 的评论）。
节点版本：v10.13.0；Windows 7 64 位；8核
节点版本：v8.1.3；CentOS 6.9；4核
bench 如下：为每个可用的 CPU 创建一个 worker，侦听端口 8000（使用 Express）并在 2 秒的模拟处理时间后回复（该过程应该完全同步到 benching，没有异步操作）。
cluster_bench.js
var cluster = require('cluster');
var express = require('express');
if(cluster.isMaster) {
var numWorkers = require('os').cpus().length;
console.log('[' + new Date().toISOString() + '] Master cluster setting up ' + numWorkers + ' workers...');
for(var i = 0; i < numWorkers; i++) {
cluster.fork();
}
cluster.on('online', function(worker) {
console.log('[' + new Date().toISOString() + '] Worker ' + (''+worker.process.pid).padStart(6, ' ') + ' is online');
});
cluster.on('exit', function(worker, code, signal) {
console.log('[' + new Date().toISOString() + '] Worker ' + (''+worker.process.pid).padStart(6, ' ') + ' died with code: ' + code + ', and signal: ' + signal);
console.log('[' + new Date().toISOString() + '] Starting a new worker');
cluster.fork();
});
} else {
var app = express();
const pid = (''+process.pid).padStart(6, ' ');
app.all('/*', function(req, res) {
const requestNum = req.query.num;
console.log('[' + new Date().toISOString() + '] Process ' + pid + ' handles query #' + requestNum);
// simulates a 10s-long process
const now = new Date().getTime();
let waittime = 2000; // 2 seconds
while (new Date().getTime() < now + waittime) { /* simulated synced processing */ };
console.log('[' + new Date().toISOString() + '] Process ' + pid + ' sends answer to query #' + requestNum);
res.send('Process ' + pid + ' says hello!');
});
var port = 8000;
var server = app.listen(port, function() {
console.log('[' + new Date().toISOString() + '] Process ' + pid + ' is listening on port ' + port);
});
}
现在我用 32 个并发请求来测试这个脚本：
cluster_client.js
const http = require('http');
// Send 32 concurrent calls
for(var i=0; i<32; i++) {
let id = (''+i).padStart(2, ' ');
console.log('[' + new Date().toISOString() + '] Request ' + id + ' launched.');
http.get('http://localhost:8000?num=' + id, (resp) => {
let data = '';
resp.on('data', chunk => data += chunk );
resp.on('end', () => console.log('[' + new Date().toISOString() + '] Request ' + id + ' - answer: ' + data) );
});
}
我希望我的呼叫由一批 n-CPU处理。
然而，我观察到这种行为：
- 第一批实际上使用了 n 个 CPU
- 后面的批次使用的 CPU 越来越少
- 最后一批只使用一个 CPU，所以最后一个请求一个接一个地得到响应，时间很长
例如，在 8 核计算机上：前 8 个请求一次处理，然后另一个 8 个请求，然后 4 个请求，4 个请求，2 个请求，2 个请求，2 个请求，1 个请求，1 个请求一次。
在 Windows 上，如果我在不重新启动服务器的情况下再次启动客户端脚本，那么只有 2 个现有工作人员将处理 32 个请求。在 CentOS 上，行为与第一次启动相同（首先使用所有 CPU，然后越来越少）。
任何工人都不会产生“退出”事件。我还在子进程事件（https://nodejs.org/api/process.html#process_process_events中描述的所有事件）上放置了带有日志的钩子，并观察到没有为任何子进程发出任何类型的事件。此外，jfriend00 已经检查了客户端使用 WireShark 实际发送的所有请求（见评论），这些请求是正确发送的。
这种行为怎么可能？
这是我从服务器获得的痕迹：
[2019-08-30T20:57:42.078Z] Master cluster setting up 8 workers...
[2019-08-30T20:57:42.781Z] Worker 1732 is online
[2019-08-30T20:57:42.798Z] Worker 208 is online
[2019-08-30T20:57:42.866Z] Worker 10868 is online
[2019-08-30T20:57:43.032Z] Worker 10232 is online
[2019-08-30T20:57:43.044Z] Worker 12356 is online
[2019-08-30T20:57:43.113Z] Worker 12500 is online
[2019-08-30T20:57:43.208Z] Worker 1196 is online
[2019-08-30T20:57:43.315Z] Worker 10948 is online
[2019-08-30T20:57:43.738Z] Process 1732 is listening on port 8000
[2019-08-30T20:57:43.779Z] Process 208 is listening on port 8000
[2019-08-30T20:57:43.891Z] Process 10868 is listening on port 8000
[2019-08-30T20:57:44.018Z] Process 10232 is listening on port 8000
[2019-08-30T20:57:44.018Z] Process 12356 is listening on port 8000
[2019-08-30T20:57:44.039Z] Process 12500 is listening on port 8000
[2019-08-30T20:57:44.097Z] Process 1196 is listening on port 8000
[2019-08-30T20:57:44.159Z] Process 10948 is listening on port 8000
[2019-08-30T20:57:49.570Z] Process 10232 handles query # 5
[2019-08-30T20:57:49.571Z] Process 10948 handles query # 0
[2019-08-30T20:57:49.596Z] Process 1732 handles query #10
[2019-08-30T20:57:49.607Z] Process 10868 handles query # 7
[2019-08-30T20:57:49.610Z] Process 1196 handles query # 2
[2019-08-30T20:57:49.611Z] Process 208 handles query # 8
[2019-08-30T20:57:49.613Z] Process 12356 handles query # 6
[2019-08-30T20:57:49.628Z] Process 12500 handles query # 4
[2019-08-30T20:57:51.586Z] Process 10232 sends answer to query # 5
[2019-08-30T20:57:51.613Z] Process 10948 sends answer to query # 0
[2019-08-30T20:57:51.620Z] Process 1732 sends answer to query #10
[2019-08-30T20:57:51.655Z] Process 10868 sends answer to query # 7
[2019-08-30T20:57:51.656Z] Process 1196 sends answer to query # 2
[2019-08-30T20:57:51.666Z] Process 10232 handles query #14
[2019-08-30T20:57:51.684Z] Process 208 sends answer to query # 8
[2019-08-30T20:57:51.693Z] Process 1732 handles query #31
[2019-08-30T20:57:51.695Z] Process 10948 handles query # 1
[2019-08-30T20:57:51.734Z] Process 12356 sends answer to query # 6
[2019-08-30T20:57:51.755Z] Process 12500 sends answer to query # 4
[2019-08-30T20:57:51.770Z] Process 1196 handles query # 3
[2019-08-30T20:57:51.774Z] Process 10868 handles query #12
[2019-08-30T20:57:51.815Z] Process 208 handles query #17
[2019-08-30T20:57:51.841Z] Process 12356 handles query # 9
[2019-08-30T20:57:51.885Z] Process 12500 handles query #13
[2019-08-30T20:57:53.671Z] Process 10232 sends answer to query #14
[2019-08-30T20:57:53.697Z] Process 1732 sends answer to query #31
[2019-08-30T20:57:53.699Z] Process 10948 sends answer to query # 1
[2019-08-30T20:57:53.709Z] Process 10948 handles query #11
[2019-08-30T20:57:53.771Z] Process 1196 sends answer to query # 3
[2019-08-30T20:57:53.781Z] Process 10868 sends answer to query #12
[2019-08-30T20:57:53.780Z] Process 1196 handles query #15
[2019-08-30T20:57:53.816Z] Process 208 sends answer to query #17
[2019-08-30T20:57:53.848Z] Process 12356 sends answer to query # 9
[2019-08-30T20:57:53.856Z] Process 12356 handles query #16
[2019-08-30T20:57:53.886Z] Process 12500 sends answer to query #13
[2019-08-30T20:57:53.895Z] Process 12500 handles query #19
[2019-08-30T20:57:55.712Z] Process 10948 sends answer to query #11
[2019-08-30T20:57:55.718Z] Process 10948 handles query #18
[2019-08-30T20:57:55.782Z] Process 1196 sends answer to query #15
[2019-08-30T20:57:55.788Z] Process 1196 handles query #21
[2019-08-30T20:57:55.856Z] Process 12356 sends answer to query #16
[2019-08-30T20:57:55.862Z] Process 12356 handles query #20
[2019-08-30T20:57:55.896Z] Process 12500 sends answer to query #19
[2019-08-30T20:57:55.901Z] Process 12500 handles query #23
[2019-08-30T20:57:57.719Z] Process 10948 sends answer to query #18
[2019-08-30T20:57:57.789Z] Process 1196 sends answer to query #21
[2019-08-30T20:57:57.863Z] Process 12356 sends answer to query #20
[2019-08-30T20:57:57.889Z] Process 12356 handles query #22
[2019-08-30T20:57:57.901Z] Process 12500 sends answer to query #23
[2019-08-30T20:57:57.919Z] Process 12500 handles query #25
[2019-08-30T20:57:59.889Z] Process 12356 sends answer to query #22
[2019-08-30T20:57:59.891Z] Process 12356 handles query #24
[2019-08-30T20:57:59.920Z] Process 12500 sends answer to query #25
[2019-08-30T20:57:59.922Z] Process 12500 handles query #27
[2019-08-30T20:58:01.892Z] Process 12356 sends answer to query #24
[2019-08-30T20:58:01.894Z] Process 12356 handles query #26
[2019-08-30T20:58:01.923Z] Process 12500 sends answer to query #27
[2019-08-30T20:58:01.926Z] Process 12500 handles query #29
[2019-08-30T20:58:03.895Z] Process 12356 sends answer to query #26
[2019-08-30T20:58:03.899Z] Process 12356 handles query #28
[2019-08-30T20:58:03.926Z] Process 12500 sends answer to query #29
[2019-08-30T20:58:05.901Z] Process 12356 sends answer to query #28
[2019-08-30T20:58:05.903Z] Process 12356 handles query #30
[2019-08-30T20:58:07.904Z] Process 12356 sends answer to query #30
从客户端：
[2019-08-30T20:57:49.293Z] Request 0 launched.
[2019-08-30T20:57:49.376Z] Request 1 launched.
[2019-08-30T20:57:49.380Z] Request 2 launched.
[2019-08-30T20:57:49.381Z] Request 3 launched.
[2019-08-30T20:57:49.384Z] Request 4 launched.
[2019-08-30T20:57:49.387Z] Request 5 launched.
[2019-08-30T20:57:49.390Z] Request 6 launched.
[2019-08-30T20:57:49.393Z] Request 7 launched.
[2019-08-30T20:57:49.396Z] Request 8 launched.
[2019-08-30T20:57:49.404Z] Request 9 launched.
[2019-08-30T20:57:49.407Z] Request 10 launched.
[2019-08-30T20:57:49.410Z] Request 11 launched.
[2019-08-30T20:57:49.413Z] Request 12 launched.
[2019-08-30T20:57:49.421Z] Request 13 launched.
[2019-08-30T20:57:49.425Z] Request 14 launched.
[2019-08-30T20:57:49.427Z] Request 15 launched.
[2019-08-30T20:57:49.435Z] Request 16 launched.
[2019-08-30T20:57:49.438Z] Request 17 launched.
[2019-08-30T20:57:49.441Z] Request 18 launched.
[2019-08-30T20:57:49.444Z] Request 19 launched.
[2019-08-30T20:57:49.452Z] Request 20 launched.
[2019-08-30T20:57:49.455Z] Request 21 launched.
[2019-08-30T20:57:49.458Z] Request 22 launched.
[2019-08-30T20:57:49.461Z] Request 23 launched.
[2019-08-30T20:57:49.469Z] Request 24 launched.
[2019-08-30T20:57:49.472Z] Request 25 launched.
[2019-08-30T20:57:49.475Z] Request 26 launched.
[2019-08-30T20:57:49.479Z] Request 27 launched.
[2019-08-30T20:57:49.487Z] Request 28 launched.
[2019-08-30T20:57:49.489Z] Request 29 launched.
[2019-08-30T20:57:49.493Z] Request 30 launched.
[2019-08-30T20:57:49.496Z] Request 31 launched.
[2019-08-30T20:57:51.637Z] Request 5 - answer: Process 10232 says hello!
[2019-08-30T20:57:51.651Z] Request 0 - answer: Process 10948 says hello!
[2019-08-30T20:57:51.654Z] Request 10 - answer: Process 1732 says hello!
[2019-08-30T20:57:51.704Z] Request 2 - answer: Process 1196 says hello!
[2019-08-30T20:57:51.727Z] Request 7 - answer: Process 10868 says hello!
[2019-08-30T20:57:51.763Z] Request 8 - answer: Process 208 says hello!
[2019-08-30T20:57:51.786Z] Request 6 - answer: Process 12356 says hello!
[2019-08-30T20:57:51.801Z] Request 4 - answer: Process 12500 says hello!
[2019-08-30T20:57:53.677Z] Request 14 - answer: Process 10232 says hello!
[2019-08-30T20:57:53.702Z] Request 31 - answer: Process 1732 says hello!
[2019-08-30T20:57:53.705Z] Request 1 - answer: Process 10948 says hello!
[2019-08-30T20:57:53.777Z] Request 3 - answer: Process 1196 says hello!
[2019-08-30T20:57:53.786Z] Request 12 - answer: Process 10868 says hello!
[2019-08-30T20:57:53.821Z] Request 17 - answer: Process 208 says hello!
[2019-08-30T20:57:53.853Z] Request 9 - answer: Process 12356 says hello!
[2019-08-30T20:57:53.891Z] Request 13 - answer: Process 12500 says hello!
[2019-08-30T20:57:55.715Z] Request 11 - answer: Process 10948 says hello!
[2019-08-30T20:57:55.786Z] Request 15 - answer: Process 1196 says hello!
[2019-08-30T20:57:55.860Z] Request 16 - answer: Process 12356 says hello!
[2019-08-30T20:57:55.898Z] Request 19 - answer: Process 12500 says hello!
[2019-08-30T20:57:57.721Z] Request 18 - answer: Process 10948 says hello!
[2019-08-30T20:57:57.792Z] Request 21 - answer: Process 1196 says hello!
[2019-08-30T20:57:57.866Z] Request 20 - answer: Process 12356 says hello!
[2019-08-30T20:57:57.903Z] Request 23 - answer: Process 12500 says hello!
[2019-08-30T20:57:59.891Z] Request 22 - answer: Process 12356 says hello!
[2019-08-30T20:57:59.922Z] Request 25 - answer: Process 12500 says hello!
[2019-08-30T20:58:01.894Z] Request 24 - answer: Process 12356 says hello!
[2019-08-30T20:58:01.925Z] Request 27 - answer: Process 12500 says hello!
[2019-08-30T20:58:03.897Z] Request 26 - answer: Process 12356 says hello!
[2019-08-30T20:58:03.928Z] Request 29 - answer: Process 12500 says hello!
[2019-08-30T20:58:05.903Z] Request 28 - answer: Process 12356 says hello!
[2019-08-30T20:58:07.906Z] Request 30 - answer: Process 12356 says hello!
正如所指出的，随着时间的流逝，一次处理的查询越来越少。最后，只有 Process #12356 仍然做了一些事情。跟踪显示没有退出任何进程。