wordpress建m域名网站,帮别人做网站犯法吗,wordpress slider插件,哪个公司要做网络推广一#xff1a;背景 1.讲故事前段时间有位朋友加微信#xff0c;说他的程序直接 CPU100%#xff0c;每次只能手工介入重启#xff0c;让我帮忙看下到底怎么回事#xff0c;哈哈#xff0c;这种CPU打满的事故#xff0c;程序员压力会非常大, 我让朋友在 CPU 高的时候抓 2 …一背景 1.讲故事前段时间有位朋友加微信说他的程序直接 CPU100%每次只能手工介入重启让我帮忙看下到底怎么回事哈哈这种CPU打满的事故程序员压力会非常大, 我让朋友在 CPU 高的时候抓 2 个 dump 下来然后发给我分析。二WinDbg 分析 1. CPU 真的被打满了吗为了防止南辕北辙一定要用 !tp 命令去验证下是不是真的 CPU 爆高。0:000 !tp
CPU utilization: 100%
Worker Thread: Total: 21 Running: 7 Idle: 0 MaxLimit: 32767 MinLimit: 4
Work Request in Queue: 3AsyncTimerCallbackCompletion TimerInfo00000000042d2430AsyncTimerCallbackCompletion TimerInfo00000000042d2f90AsyncTimerCallbackCompletion TimerInfo000000000420c150
--------------------------------------
Number of Timers: 0
--------------------------------------
Completion Port Thread:Total: 18 Free: 9 MaxFree: 8 CurrentLimit: 18 MaxLimit: 1000 MinLimit: 4从卦中看确实 100%太牛了而且 WorkRequest 还有任务堆积现象确认无疑后接下来看下是谁引发的2. 谁导致的 CPU 爆高根据惯例首先怀疑是不是 GC 触发所致可以用 !t 查看下线程列表观察下有没有 GC 字样。:000 !t
ThreadCount: 53
UnstartedThread: 0
BackgroundThread: 53
PendingThread: 0
DeadThread: 0
Hosted Runtime: noLock ID OSID ThreadOBJ State GC Mode GC Alloc Context Domain Count Apt Exception4 1 1240 00000000021cdf30 2a220 Preemptive 0000000000000000:0000000000000000 00000000021d94c0 0 MTA 23 2 4db4 00000000041cdaa0 2b220 Preemptive 0000000000000000:0000000000000000 00000000021d94c0 0 MTA (Finalizer) ...65 156 22f4 000000000b1a3f60 8029220 Preemptive 00000004527751F0:0000000452775EE8 00000000021d94c0 0 MTA (Threadpool Completion Port) 66 205 2ef8 000000000b1a1080 8029220 Preemptive 0000000157641DE0:00000001576435B0 00000000021d94c0 0 MTA (Threadpool Completion Port) ...从卦中看没有 GC 字样也表明这个程序并不是由 GC 触发所致接下来该怎么排查呢一般来说 CPU 的爆高是由线程抬起来的所以接下来就是看下 CPU 的档次和各个线程栈看有没有什么新线索, 可以使用 ~*e !clrstack 。0:000 !cpuid
CP F/M/S Manufacturer MHz0 6,79,1 unavailable 22991 6,79,1 unavailable 22992 6,79,1 unavailable 22993 6,79,1 unavailable 22990:000 ~*e !clrstack
OS Thread Id: 0x2cc4 (68)Child SP IP Call Site
000000000c14e758 00007ffadeb86e4a [GCFrame: 000000000c14e758]
000000000c14e840 00007ffadeb86e4a [GCFrame: 000000000c14e840]
000000000c14e878 00007ffadeb86e4a [HelperMethodFrame: 000000000c14e878] System.Threading.Monitor.Enter(System.Object)
000000000c14e970 00007ffaceb40491 System.Net.ConnectionGroup.Disassociate(System.Net.Connection) [f:\dd\NDP\fx\src\net\System\Net\_ConnectionGroup.cs 148]
000000000c14e9d0 00007ffaceb3fc93 System.Net.Connection.PrepareCloseConnectionSocket(System.Net.ConnectionReturnResult ByRef) [f:\dd\NDP\fx\src\net\System\Net\_Connection.cs 3048]
000000000c14eaa0 00007ffacf139bfb System.Net.Connection.HandleError(Boolean, Boolean, System.Net.WebExceptionStatus, System.Net.ConnectionReturnResult ByRef) [f:\dd\NDP\fx\src\net\System\Net\_Connection.cs 3119]
000000000c14eb00 00007ffacebc4118 System.Net.Connection.ReadComplete(Int32, System.Net.WebExceptionStatus) [f:\dd\NDP\fx\src\net\System\Net\_Connection.cs 3387]
000000000c14eb80 00007ffacebe3dc5 System.Net.LazyAsyncResult.Complete(IntPtr) [f:\dd\NDP\fx\src\net\System\Net\_LazyAsyncResult.cs 415]
000000000c14ebe0 00007ffacebe3d07 System.Net.LazyAsyncResult.ProtectedInvokeCallback(System.Object, IntPtr) [f:\dd\NDP\fx\src\net\System\Net\_LazyAsyncResult.cs 368]
000000000c14ec20 00007ffacf3a476f System.Net.Security._SslStream.StartFrameBody(Int32, Byte[], Int32, Int32, System.Net.AsyncProtocolRequest)
000000000c14ec80 00007ffacebb3ed8 System.Net.Security._SslStream.ReadHeaderCallback(System.Net.AsyncProtocolRequest) [f:\dd\NDP\fx\src\net\System\Net\SecureProtocols\_SslStream.cs 1007]
000000000c14ece0 00007ffacebae5ee System.Net.AsyncProtocolRequest.CompleteRequest(Int32) [f:\dd\NDP\fx\src\net\System\Net\SecureProtocols\_HelperAsyncResults.cs 142]
000000000c14ed10 00007ffacf3a3567 System.Net.FixedSizeReader.CheckCompletionBeforeNextRead(Int32)
000000000c14ed40 00007ffacebae507 System.Net.FixedSizeReader.ReadCallback(System.IAsyncResult) [f:\dd\NDP\fx\src\net\System\Net\SecureProtocols\_FixedSizeReader.cs 148]
000000000c14ed90 00007ffacebe3dc5 System.Net.LazyAsyncResult.Complete(IntPtr) [f:\dd\NDP\fx\src\net\System\Net\_LazyAsyncResult.cs 415]
000000000c14edf0 00007ffadcbe3a63 System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean) [f:\dd\ndp\clr\src\BCL\system\threading\executioncontext.cs 954]
000000000c14eec0 00007ffadcbe38f4 System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean) [f:\dd\ndp\clr\src\BCL\system\threading\executioncontext.cs 902]
000000000c14eef0 00007ffadcbe38c2 System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object) [f:\dd\ndp\clr\src\BCL\system\threading\executioncontext.cs 891]
000000000c14ef40 00007ffaceba60cf System.Net.ContextAwareResult.Complete(IntPtr) [f:\dd\NDP\fx\src\net\System\Net\_ContextAwareResult.cs 463]
000000000c14ef90 00007ffacebe3d07 System.Net.LazyAsyncResult.ProtectedInvokeCallback(System.Object, IntPtr) [f:\dd\NDP\fx\src\net\System\Net\_LazyAsyncResult.cs 368]
000000000c14efd0 00007ffaceba5e2f System.Net.Sockets.BaseOverlappedAsyncResult.CompletionPortCallback(UInt32, UInt32, System.Threading.NativeOverlapped*) [f:\dd\NDP\fx\src\net\System\Net\Sockets\_BaseOverlappedAsyncResult.cs 399]
000000000c14f040 00007ffadcc2ffef System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32, UInt32, System.Threading.NativeOverlapped*) [f:\dd\ndp\clr\src\BCL\system\threading\overlapped.cs 135]
000000000c14f1f0 00007ffade9a6d93 [GCFrame: 000000000c14f1f0] OS Thread Id: 0x5d6c (70)Child SP IP Call Site
000000000943e920 00007ffacf139bfb System.Net.Connection.HandleError(Boolean, Boolean, System.Net.WebExceptionStatus, System.Net.ConnectionReturnResult ByRef) OS Thread Id: 0x4ad4 (75)Child SP IP Call Site
...
000000000c94e5a0 00007ffacf139bfb System.Net.Connection.HandleError(Boolean, Boolean, System.Net.WebExceptionStatus, System.Net.ConnectionReturnResult ByRef)
...OS Thread Id: 0x1d70 (80)Child SP IP Call Site
...
000000000d24e3a0 00007ffacf139bfb System.Net.Connection.HandleError(Boolean, Boolean, System.Net.WebExceptionStatus, System.Net.ConnectionReturnResult ByRef) [f:\dd\NDP\fx\src\net\System\Net\_Connection.cs 3119]
...从线程栈上看这个 CPU 是 4个核刚好对应着 4 个 HandleError 报错看样子是什么网络出问题了接下来切到 80 号线程看一下有没有什么异常类。0:000 ~80s
clr!AwareLock::Contention0x194:
00007ffadeb86e40 4883e801 sub rax,1
0:080 !mdso
Thread 80:
Location Object Type
------------------------------------------------------------
000000000d24e098 000000015765e028 System.Net.WebException
000000000d24e0f8 0000000340b07110 System.Collections.ArrayList
000000000d24e110 000000015765e2b8 System.Net.HttpWebRequest[]
000000000d24e1c0 0000000340b070b8 System.Net.ConnectionGroup
000000000d24e258 0000000144a79678 System.Net.Connection0:080 !mdt 000000015765e028
000000015765e028 (System.Net.WebException)_className:NULL (System.String)_exceptionMethod:NULL (System.Reflection.MethodBase)_exceptionMethodString:NULL (System.String)_message:000000015765df70 (System.String) Length77, StringThe underlying connection was closed: The connection was closed unexpectedly....果然看到了 System.Net.WebException, 从异常信息看貌似是 连接关闭了到这里我就有了一个大胆的猜测是不是高频的异常输出导致的 CPU 爆高呢为了验证可以到托管堆上找下 WebException 的个数。0:080 !dumpheap -stat
Statistics:MT Count TotalSize Class Name
...
00007ffacecc38b0 13315 2343440 System.Net.WebException
00007ffadcdf6570 11369 1909992 System.IO.IOException
00007ffadcdf5fb8 13380 2247840 System.ObjectDisposedException
...看到这么多异常还是挺吓人的刚好朋友抓了两个dump可以做个比较。0:048 !dumpheap -stat
Statistics:MT Count TotalSize Class Name
00007ffacecc38b0 26745 4707120 System.Net.WebException
00007ffadcdf6570 26722 4489296 System.IO.IOException
00007ffadcdf5fb8 28745 4829160 System.ObjectDisposedException可以看到2 min 之内异常增加了合计 4w 左右这就验证了程序确实是疯狂的抛异常在 Windows 平台上不管是硬件异常还是软件异常都由 Windows SEH 异常处理框架统一处理会出现用户态和内核态的切换这样疯狂的抛出必然会导致 CPU 爆高终于找到原因了接下来就是寻找诱发因素。3. 异常是谁诱发的再回头看 HandleError 函数的调用栈都是底层的库函数从线程栈的 PerformIOCompletionCallback 函数来看是 IO线程 诱发的能被 IO 线程兜到是因为这是做了异步处理既然是 异步自然 OverlappedData 也会非常多。0:080 !gchandles -stat
Statistics:MT Count TotalSize Class Name
00007ffadc6f7b98 14511 1625232 System.Threading.OverlappedData
Total 17550 objectsHandles:Strong Handles: 426Pinned Handles: 23Async Pinned Handles: 14511Ref Count Handles: 24Weak Long Handles: 2430Weak Short Handles: 132SizedRef Handles: 4说明此时有大概 1.5w 的异步请求待回头请求量还是蛮大的但还是没找到异常的用户代码只能找下到底是谁发起了什么请求。0:080 !mdso
Thread 80:
Location Object Type
------------------------------------------------------------
...
000000000d24e488 0000000358c57918 System.Net.HttpWebRequest
000000000d24e2e8 00000001407b5b40 System.String net_io_readfailure
...0:080 !mdt -r:2 0000000358c57918
0000000358c57918 (System.Net.HttpWebRequest)_Uri:0000000358c57210 (System.Uri)m_String:00000002407ee430 (System.String) Length98, Stringhttps://api.xxxx/peer_messages....可以看到请求的连接是 https://api.xxxx/peer_messages是一个第三方的API接口 由于底层的连接关闭导致了最后 net_io_readfailure。把所有的信息整合一下就是当请求量大了之后访问 https://api.xxxx/peer_messages 会出问题对方关闭了底层连接导致客户端这边请求出现了大量 IO 回调异常IOException: Unable to read data from the transport connection: The connection was closed.2min之间多达合计 4w 的异常抛出进而引发 CPU 爆高将信息告诉了朋友让朋友重点关注下 https://api.xxxx/peer_messages 这个连接。三总结 这次生产事故主要是由于高峰期请求量过大由于某种原因 Socket 连接关闭导致了大量的异步回调异常。解决方法在调用端做好限流据朋友说减少了不必要的 https://api.xxxx/peer_messages 调用目前没有出现 CPU 爆高现象。
