由于項(xiàng)目需要，用jmeter做了一下壓測(cè)總共發(fā)送20W次的請(qǐng)求，設(shè)置的并發(fā)為1k。然而進(jìn)行到最后發(fā)現(xiàn)后面的請(qǐng)求幾乎全部failed，添加結(jié)果樹后看到client報(bào)錯(cuò)。內(nèi)容如下

java.net.NoRouteToHostException: Can't assign requested address (Address not available)
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:589)
    at org.apache.http.conn.ssl.SSLConnectionSocketFactory.connectSocket(SSLConnectionSocketFactory.java:339)
    at org.apache.jmeter.protocol.http.sampler.hc.LazyLayeredConnectionSocketFactory.connectSocket(LazyLayeredConnectionSocketFactory.java:92)
    at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:142)
    at org.apache.jmeter.protocol.http.sampler.HTTPHC4Impl$JMeterDefaultHttpClientConnectionOperator.connect(HTTPHC4Impl.java:331)
    at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:373)
    at org.apache.http.impl.execchain.MainClientExec.establishRoute(MainClientExec.java:394)
    at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:237)
    at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:185)
    at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:89)
    at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110)
    at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:185)
    at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:83)
    at org.apache.jmeter.protocol.http.sampler.HTTPHC4Impl.executeRequest(HTTPHC4Impl.java:832)
    at org.apache.jmeter.protocol.http.sampler.HTTPHC4Impl.sample(HTTPHC4Impl.java:570)
    at org.apache.jmeter.protocol.http.sampler.HTTPSamplerProxy.sample(HTTPSamplerProxy.java:67)
    at org.apache.jmeter.protocol.http.sampler.HTTPSamplerBase.sample(HTTPSamplerBase.java:1231)
    at org.apache.jmeter.protocol.http.sampler.HTTPSamplerBase.sample(HTTPSamplerBase.java:1220)
    at org.apache.jmeter.threads.JMeterThread.doSampling(JMeterThread.java:622)
    at org.apache.jmeter.threads.JMeterThread.executeSamplePackage(JMeterThread.java:546)
    at org.apache.jmeter.threads.JMeterThread.processSampler(JMeterThread.java:486)
    at org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:253)
    at java.lang.Thread.run(Thread.java:748)

然后進(jìn)行了一系列的google。大部分文章說(shuō)的是port range的端口號(hào)用完導(dǎo)致的問(wèn)題
用 netstat 命令查看了一下大部分鏈接都是在等待，確實(shí)端口被占用完了，然后一波操作改了范圍

netstat -nt | awk '/^tcp/ {++state[$NF]} END {for(key in state) print key,"t",state[key]}'
[root@node011086 conf]# sysctl -a | grep range
net.ipv4.ip_local_port_range = 15000    65000

然后進(jìn)行了一波壓測(cè)發(fā)現(xiàn)又報(bào)錯(cuò)了。平均響應(yīng)時(shí)間在200ms以內(nèi)。百思不得其解。網(wǎng)上大部分操作是設(shè)置端口復(fù)用以及回收等操作，但是在執(zhí)行回收操作命令的時(shí)候總是提示文件不存在。

net.ipv4.tcp_tw_reuse = 1

后來(lái)仔細(xì)看了一下官方說(shuō)明發(fā)現(xiàn)這幾個(gè)參數(shù)都是對(duì)長(zhǎng)連接進(jìn)行的優(yōu)化，馬上想到j(luò)meter是否有keep alive 選項(xiàng)。取消勾選后果然一切正常