在重负载下,我们的应用程序使得一个强大的服务器的CPU使用率达到100%。阅读进程转储,在查看线程时,其中一些线程已经运行了10分钟。当使用!CLRStack时,它们中的任何一个都没有给我任何见解。
!runaway 给了我:
0:030> !runaway
User Mode Time
Thread Time
53:2e804 0 days 0:10:04.703
30:31894 0 days 0:07:51.593
33:47100 0 days 0:07:24.890
42:11e54 0 days 0:06:45.875
35:35e18 0 days 0:06:07.578
41:54464 0 days 0:05:49.796
47:57700 0 days 0:05:45.000
44:3c2d4 0 days 0:05:44.265
32:3898c 0 days 0:05:43.593
50:54894 0 days 0:05:41.968
51:5bc58 0 days 0:05:40.921
43:14af4 0 days 0:05:40.734
48:35074 0 days 0:05:40.406
...
在其中一个线程上调用!DumpStack,我得到了以下结果:
0000001ab442f900 00007ff9ef4c1148 KERNELBASE!WaitForSingleObjectEx+0x94, calling ntdll!NtWaitForSingleObject
0000001ab442f980 00007ff9e920beb2 clr!SVR::gc_heap::compute_new_dynamic_data+0x17b, calling clr!SVR::gc_heap::desired_new_allocation
0000001ab442f9a0 00007ff9e90591eb clr!CLREventWaitHelper2+0x38, calling kernel32!WaitForSingleObjectEx
0000001ab442f9b0 00007ff9e90e0d2c clr!WriteBarrierManager::UpdateEphemeralBounds+0x1c, calling clr!WriteBarrierManager::NeedDifferentWriteBarrier
0000001ab442f9e0 00007ff9e9059197 clr!CLREventWaitHelper+0x1f, calling clr!CLREventWaitHelper2
0000001ab442fa40 00007ff9e9059120 clr!CLREventBase::WaitEx+0x70, calling clr!CLREventWaitHelper
0000001ab442fa70 00007ff9ef4c149c KERNELBASE!SetEvent+0xc, calling ntdll!NtSetEvent
0000001ab442faa0 00007ff9e90ef1e1 clr!SVR::gc_heap::set_gc_done+0x22, calling clr!CLREventBase::Set
0000001ab442fad0 00007ff9e90e9331 clr!SVR::gc_heap::gc_thread_function+0x8a, calling clr!CLREventBase::WaitEx
0000001ab442fb00 00007ff9e92048e7 clr!SVR::gc_heap::gc_thread_stub+0x7a, calling clr!SVR::gc_heap::gc_thread_function
0000001ab442fb60 00007ff9e91a0318 clr!Thread::CLRSetThreadStackGuarantee+0x48, calling kernel32!SetThreadStackGuaranteeStub
0000001ab442fb90 00007ff9e91a01ef clr!Thread::CommitThreadStack+0x10, calling clr!Thread::CLRSetThreadStackGuarantee
0000001ab442fbd0 00007ff9e910df0b clr!ClrFlsSetValue+0x57, calling kernel32!SetLastErrorStub
0000001ab442fc00 00007ff9e92048dc clr!SVR::gc_heap::gc_thread_stub+0x6f, calling clr!_chkstk
0000001ab442fc40 00007ff9f0d316ad kernel32!BaseThreadInitThunk+0xd
0000001ab442fc70 00007ff9f1e54409 ntdll!RtlUserThreadStart+0x1d
这告诉我什么?我看到很多对CLR的调用,但是我无法理解问题出在哪里。在Thomas建议使用.reload命令之后,现在我可以看到GC的调用。
更新1
运行xperf后,每个w3wp.exe占用大约45%的CPU。通过其中一个进行过滤并根据函数分组,有一个带有“?”标签的函数负责13.62%,其他小于2.67%。我怎样才能知道这个“?”是什么?
更新2
再次运行xperf,函数JIT_MonEnterWorker_InlineGetThread_GetThread_PatchLabel
占CPU使用率的12.31%。那个“?”函数仍然存在。
按堆栈分组:
Line #, Stack, Count, Weight (in view), TimeStamp, % Weight
2, |- ?!?, 501191, 501222.365294, , 35.51
3, | |- clr.dll!JITutil_MonContention, 215749, 215752.552227, , 15.28
4, | |- clr.dll!JIT_MonEnterWorker_InlineGetThread_GetThread_PatchLabel, 170804, 170777.100191, , 12.10
如您所见,这两个进程占用了超过27%的CPU使用率(每个进程),因此非常重要。
更新3
在使用wpr.exe(由@magicandre1981建议)后:
wpr.exe -start cpu and wpr -stop result.etl
我发现FormsAuthentication和一些紧急路径上不必要的Ninject调用导致了大约16%的CPU使用率。我仍然不理解运行时间超过10分钟的线程。
更新4
尝试了DebugDiag(来自@leppie的建议),它只是确认挂起的线程都类似于:
Thread ID: 53 Total CPU Time: 00:09:11.406 Entry Point for Thread: clr!Thread::intermediateThreadProc
Thread ID: 35 Total CPU Time: 00:07:26.046 Entry Point for Thread: clr!SVR::gc_heap::gc_thread_stub
Thread ID: 50 Total CPU Time: 00:07:01.515 Entry Point for Thread: clr!SVR::gc_heap::gc_thread_stub
Thread ID: 29 Total CPU Time: 00:06:02.264 Entry Point for Thread: clr!SVR::gc_heap::gc_thread_stub
Thread ID: 31 Total CPU Time: 00:06:41.281 Entry Point for Thread: clr!SVR::gc_heap::gc_thread_stub
或者是由于 StackExchange.Redis 的原因:
DomainBoundILStubClass.IL_STUB_PInvoke(Int32, IntPtr[], IntPtr[], IntPtr[], TimeValue ByRef)+e1
[[InlinedCallFrame] (StackExchange.Redis.SocketManager.select)] StackExchange.Redis.SocketManager.select(Int32, IntPtr[], IntPtr[], IntPtr[], TimeValueByRef)
StackExchange.Redis.SocketManager.ReadImpl()+889
StackExchange.Redis.SocketManager.Read()+66
或者[[GCFrame]]
[[HelperMethodFrame_1OBJ] (System.Threading.Monitor.ObjWait)] System.Threading.Monitor.ObjWait(Boolean, Int32, System.Object)
mscorlib_ni!System.Threading.Monitor.Wait(System.Object, Int32)+19
StackExchange.Redis.ConnectionMultiplexer.ExecuteSyncImpl[[System.__Canon, mscorlib]](StackExchange.Redis.Message, StackExchange.Redis.ResultProcessor`1, StackExchange.Redis.ServerEndPoint)+24f
StackExchange.Redis.RedisBase.ExecuteSync[[System.__Canon, mscorlib]](StackExchange.Redis.Message, StackExchange.Redis.ResultProcessor`1, StackExchange.Redis.ServerEndPoint)+77
[[StubHelperFrame]]
StackExchange.Redis.RedisDatabase.SetMembers(StackExchange.Redis.RedisKey, StackExchange.Redis.CommandFlags)+ee
WaitForSingleObjectEx()
中等待的对象处于等待状态而不是执行状态,所以它不会消耗CPU。当线程陷入死锁时,它们也不会消耗CPU,因为它们都在等待资源。 - Thomas Weller