Reply to thread

Message

Re: Help analyzing audio buzzes / DPC latency issue ?

Thank you writhziden for you reply.
I've started digging into the Stack and found that at the moment of a stutter, the function ntoskrnl.exe!KxWaitForLockOwnerShip is called 66 times and runs for a total of 66 ms. The same thing happens concurrently on four different cores.
[ATTACH]26037[/ATTACH]

If we reverse the column order we can see which cores are occupied by that function. My CPU has 8 logical cores but 4 physical ones, so that may explain why the system stutters when only four cores are clogged. Another function, KxWaitForSpinLockAndAcquire is running on the four other cores.
[ATTACH]26039[/ATTACH]

I don't know what is a spinlock exactly, nor what it could be waiting for. Any ideas?

Here are the contents of the stacks leading up to the four 66 ms loops (most recent call at the bottom):
CPU#5:
[CODE] ntoskrnl.exe!KiStartSystemThread
ntoskrnl.exe!PspSystemThreadStartup
ntoskrnl.exe!ExpWorkerThread
ntoskrnl.exe!IopProcessWorkItem
tunnel.sys!LwWorker
tunnel.sys!TeredoWfpInjectionWorker
fwpkclnt.sys!FwpsInjectTransportSendAsync0
fwpkclnt.sys!FwppInjectTransportSendAsync
fwpkclnt.sys!NetioExpandKernelStackAndCallout
ntoskrnl.exe!KeExpandKernelStackAndCalloutInternal
fwpkclnt.sys!FwppInjectionStackCallout
tcpip.sys!IppInspectInjectTlSend
tcpip.sys!IppSendDatagramsCommon
tcpip.sys!IppJoinPath
tcpip.sys!IppFindOrCreatePath
ntoskrnl.exe!KeAcquireInStackQueuedSpinLockAtDpcLevel
ntoskrnl.exe!KxWaitForLockOwnerShip
[/CODE]
CPU#4:
[CODE] ntdll.dll!RtlUserThreadStart
kernel32.dll!BaseThreadInitThunk
qbittorrent.exe!<PDB not found>
qbittorrent.exe!<PDB not found>
qbittorrent.exe!<PDB not found>
qbittorrent.exe!<PDB not found>
qbittorrent.exe!<PDB not found>
qbittorrent.exe!<PDB not found>
qbittorrent.exe!<PDB not found>
qbittorrent.exe!<PDB not found>
qbittorrent.exe!<PDB not found>
qbittorrent.exe!<PDB not found>
qbittorrent.exe!<PDB not found>
qbittorrent.exe!<PDB not found>
qbittorrent.exe!<PDB not found>
qbittorrent.exe!<PDB not found>
qbittorrent.exe!<PDB not found>
qbittorrent.exe!<PDB not found>
ws2_32.dll!WSASendTo
mswsock.dll!WSPSendTo
ntdll.dll!ZwDeviceIoControlFile
ntoskrnl.exe!KiSystemServiceCopyEnd
ntoskrnl.exe!NtDeviceIoControlFile
ntoskrnl.exe!IopXxxControlFile
afd.sys!AfdFastIoDeviceControl
afd.sys!AfdFastDatagramSend
tcpip.sys!UdpTlProviderSendMessages
ntoskrnl.exe!KeExpandKernelStackAndCalloutInternal
tcpip.sys!UdpTlProviderSendMessagesCalloutRoutine
tcpip.sys!UdpSendMessages
tcpip.sys!IppJoinPath
tcpip.sys!IppFindOrCreatePath
ntoskrnl.exe!KeAcquireInStackQueuedSpinLockAtDpcLevel
ntoskrnl.exe!KxWaitForLockOwnerShip
[/CODE]
CPU#0:
[CODE] ntoskrnl.exe!KiStartSystemThread
ntoskrnl.exe!PspSystemThreadStartup
ndis.sys!ndisReceiveWorkerThread
ndis.sys!ndisQueuedMiniportDpcWorkItem
rt640x64.sys!<PDB not found>
rt640x64.sys!<PDB not found>
ndis.sys!NdisMIndicateReceiveNetBufferLists
ndis.sys!ndisCallReceiveHandler
ndis.sys!ndisMTopReceiveNetBufferLists
ndis.sys!ndisMIndicateNetBufferListsToOpen
tcpip.sys!FlReceiveNetBufferListChain
ntoskrnl.exe!KeExpandKernelStackAndCalloutInternal
tcpip.sys!FlReceiveNetBufferListChainCalloutRoutine
tcpip.sys!IpFlcReceivePreValidatedPackets
tcpip.sys!IppFlcReceivePacketsCore
tcpip.sys!IppDispatchReceivePacketHelper
ntoskrnl.exe!KeAcquireInStackQueuedSpinLockAtDpcLevel
ntoskrnl.exe!KxWaitForLockOwnerShip
[/CODE]
CPU#2:
[CODE] ntoskrnl.exe!KiStartSystemThread
ntoskrnl.exe!PspSystemThreadStartup
ndis.sys!ndisReceiveWorkerThread
ndis.sys!ndisQueuedMiniportDpcWorkItem
rt640x64.sys!<PDB not found>
rt640x64.sys!<PDB not found>
rt640x64.sys!<PDB not found>
rt640x64.sys!<PDB not found>
ndis.sys!NdisMIndicateReceiveNetBufferLists
ndis.sys!ndisCallReceiveHandler
ndis.sys!ndisMTopReceiveNetBufferLists
ndis.sys!ndisMIndicateNetBufferListsToOpen
tcpip.sys!FlReceiveNetBufferListChain
ntoskrnl.exe!KeExpandKernelStackAndCalloutInternal
tcpip.sys!FlReceiveNetBufferListChainCalloutRoutine
tcpip.sys!FlpReceiveNonPreValidatedNetBufferListChain
tcpip.sys!IppFlcReceivePacketsCore
tcpip.sys!IppDispatchReceivePacketHelper
ntoskrnl.exe!KeAcquireInStackQueuedSpinLockAtDpcLevel
ntoskrnl.exe!KxWaitForLockOwnerShip
[/CODE]
I have captured a second trace in which only three cores seem to be occupied by ntoskrnl.exe!KxWaitForLockOwnerShip. I'm still looking into it.

<blockquote data-quote="Cutter" data-source="post: 181140" data-attributes="member: 22080">Re: Help analyzing audio buzzes / DPC latency issue ?Thank you writhziden for you reply.I&#039;ve started digging into the Stack and found that at the moment of a stutter, the function ntoskrnl.exe!KxWaitForLockOwnerShip is called 66 times and runs for a total of 66 ms. The same thing happens concurrently on four different cores.[ATTACH]26037[/ATTACH]If we reverse the column order we can see which cores are occupied by that function. My CPU has 8 logical cores but 4 physical ones, so that may explain why the system stutters when only four cores are clogged. Another function, KxWaitForSpinLockAndAcquire is running on the four other cores.[ATTACH]26039[/ATTACH]I don&#039;t know what is a spinlock exactly, nor what it could be waiting for. Any ideas?Here are the contents of the stacks leading up to the four 66 ms loops (most recent call at the bottom):CPU#5:[CODE]&nbsp; ntoskrnl.exe!KiStartSystemThread&nbsp; ntoskrnl.exe!PspSystemThreadStartup&nbsp; ntoskrnl.exe!ExpWorkerThread&nbsp; ntoskrnl.exe!IopProcessWorkItem&nbsp; tunnel.sys!LwWorker&nbsp; tunnel.sys!TeredoWfpInjectionWorker&nbsp; fwpkclnt.sys!FwpsInjectTransportSendAsync0&nbsp; fwpkclnt.sys!FwppInjectTransportSendAsync&nbsp; fwpkclnt.sys!NetioExpandKernelStackAndCallout&nbsp; ntoskrnl.exe!KeExpandKernelStackAndCalloutInternal&nbsp; fwpkclnt.sys!FwppInjectionStackCallout&nbsp; tcpip.sys!IppInspectInjectTlSend&nbsp; tcpip.sys!IppSendDatagramsCommon&nbsp; tcpip.sys!IppJoinPath&nbsp; tcpip.sys!IppFindOrCreatePath&nbsp; ntoskrnl.exe!KeAcquireInStackQueuedSpinLockAtDpcLevel&nbsp; ntoskrnl.exe!KxWaitForLockOwnerShip[/CODE]CPU#4:[CODE]&nbsp; ntdll.dll!RtlUserThreadStart&nbsp; kernel32.dll!BaseThreadInitThunk&nbsp; qbittorrent.exe!&lt;PDB not found&gt;&nbsp; qbittorrent.exe!&lt;PDB not found&gt;&nbsp; qbittorrent.exe!&lt;PDB not found&gt;&nbsp; qbittorrent.exe!&lt;PDB not found&gt;&nbsp; qbittorrent.exe!&lt;PDB not found&gt;&nbsp; qbittorrent.exe!&lt;PDB not found&gt;&nbsp; qbittorrent.exe!&lt;PDB not found&gt;&nbsp; qbittorrent.exe!&lt;PDB not found&gt;&nbsp; qbittorrent.exe!&lt;PDB not found&gt;&nbsp; qbittorrent.exe!&lt;PDB not found&gt;&nbsp; qbittorrent.exe!&lt;PDB not found&gt;&nbsp; qbittorrent.exe!&lt;PDB not found&gt;&nbsp; qbittorrent.exe!&lt;PDB not found&gt;&nbsp; qbittorrent.exe!&lt;PDB not found&gt;&nbsp; qbittorrent.exe!&lt;PDB not found&gt;&nbsp; qbittorrent.exe!&lt;PDB not found&gt;&nbsp; ws2_32.dll!WSASendTo&nbsp; mswsock.dll!WSPSendTo&nbsp; ntdll.dll!ZwDeviceIoControlFile&nbsp; ntoskrnl.exe!KiSystemServiceCopyEnd&nbsp; ntoskrnl.exe!NtDeviceIoControlFile&nbsp; ntoskrnl.exe!IopXxxControlFile&nbsp; afd.sys!AfdFastIoDeviceControl&nbsp; afd.sys!AfdFastDatagramSend&nbsp; tcpip.sys!UdpTlProviderSendMessages&nbsp; ntoskrnl.exe!KeExpandKernelStackAndCalloutInternal&nbsp; tcpip.sys!UdpTlProviderSendMessagesCalloutRoutine&nbsp; tcpip.sys!UdpSendMessages&nbsp; tcpip.sys!IppJoinPath&nbsp; tcpip.sys!IppFindOrCreatePath&nbsp; ntoskrnl.exe!KeAcquireInStackQueuedSpinLockAtDpcLevel&nbsp; ntoskrnl.exe!KxWaitForLockOwnerShip[/CODE]CPU#0:[CODE]&nbsp; ntoskrnl.exe!KiStartSystemThread&nbsp; ntoskrnl.exe!PspSystemThreadStartup&nbsp; ndis.sys!ndisReceiveWorkerThread&nbsp; ndis.sys!ndisQueuedMiniportDpcWorkItem&nbsp; rt640x64.sys!&lt;PDB not found&gt;&nbsp; rt640x64.sys!&lt;PDB not found&gt;&nbsp; ndis.sys!NdisMIndicateReceiveNetBufferLists&nbsp; ndis.sys!ndisCallReceiveHandler&nbsp; ndis.sys!ndisMTopReceiveNetBufferLists&nbsp; ndis.sys!ndisMIndicateNetBufferListsToOpen&nbsp; tcpip.sys!FlReceiveNetBufferListChain&nbsp; ntoskrnl.exe!KeExpandKernelStackAndCalloutInternal&nbsp; tcpip.sys!FlReceiveNetBufferListChainCalloutRoutine&nbsp; tcpip.sys!IpFlcReceivePreValidatedPackets&nbsp; tcpip.sys!IppFlcReceivePacketsCore&nbsp; tcpip.sys!IppDispatchReceivePacketHelper&nbsp; ntoskrnl.exe!KeAcquireInStackQueuedSpinLockAtDpcLevel&nbsp; ntoskrnl.exe!KxWaitForLockOwnerShip[/CODE]CPU#2:[CODE]&nbsp; ntoskrnl.exe!KiStartSystemThread&nbsp; ntoskrnl.exe!PspSystemThreadStartup&nbsp; ndis.sys!ndisReceiveWorkerThread&nbsp; ndis.sys!ndisQueuedMiniportDpcWorkItem&nbsp; rt640x64.sys!&lt;PDB not found&gt;&nbsp; rt640x64.sys!&lt;PDB not found&gt;&nbsp; rt640x64.sys!&lt;PDB not found&gt;&nbsp; rt640x64.sys!&lt;PDB not found&gt;&nbsp; ndis.sys!NdisMIndicateReceiveNetBufferLists&nbsp; ndis.sys!ndisCallReceiveHandler&nbsp; ndis.sys!ndisMTopReceiveNetBufferLists&nbsp; ndis.sys!ndisMIndicateNetBufferListsToOpen&nbsp; tcpip.sys!FlReceiveNetBufferListChain&nbsp; ntoskrnl.exe!KeExpandKernelStackAndCalloutInternal&nbsp; tcpip.sys!FlReceiveNetBufferListChainCalloutRoutine&nbsp; tcpip.sys!FlpReceiveNonPreValidatedNetBufferListChain&nbsp; tcpip.sys!IppFlcReceivePacketsCore&nbsp; tcpip.sys!IppDispatchReceivePacketHelper&nbsp; ntoskrnl.exe!KeAcquireInStackQueuedSpinLockAtDpcLevel&nbsp; ntoskrnl.exe!KxWaitForLockOwnerShip[/CODE]I have captured a second trace in which only three cores seem to be occupied by ntoskrnl.exe!KxWaitForLockOwnerShip. I&#039;m still looking into it.</blockquote>

[QUOTE="Cutter, post: 181140, member: 22080"] [b]Re: Help analyzing audio buzzes / DPC latency issue ?[/b] Thank you writhziden for you reply. I've started digging into the Stack and found that at the moment of a stutter, the function [B]ntoskrnl.exe!KxWaitForLockOwnerShip[/B] is called 66 times and runs for a total of 66 ms. The same thing happens concurrently on four different cores. [ATTACH=CONFIG]26037.vB[/ATTACH] If we reverse the column order we can see which cores are occupied by that function. My CPU has 8 logical cores but 4 physical ones, so that may explain why the system stutters when only four cores are clogged. Another function, [B]KxWaitForSpinLockAndAcquire[/B] is running on the [B]four other cores[/B]. [ATTACH=CONFIG]26039.vB[/ATTACH] I don't know what is a spinlock exactly, nor what it could be waiting for. Any ideas? Here are the contents of the stacks leading up to the four 66 ms loops (most recent call at the bottom): CPU#5: [CODE] ntoskrnl.exe!KiStartSystemThread ntoskrnl.exe!PspSystemThreadStartup ntoskrnl.exe!ExpWorkerThread ntoskrnl.exe!IopProcessWorkItem tunnel.sys!LwWorker tunnel.sys!TeredoWfpInjectionWorker fwpkclnt.sys!FwpsInjectTransportSendAsync0 fwpkclnt.sys!FwppInjectTransportSendAsync fwpkclnt.sys!NetioExpandKernelStackAndCallout ntoskrnl.exe!KeExpandKernelStackAndCalloutInternal fwpkclnt.sys!FwppInjectionStackCallout tcpip.sys!IppInspectInjectTlSend tcpip.sys!IppSendDatagramsCommon tcpip.sys!IppJoinPath tcpip.sys!IppFindOrCreatePath ntoskrnl.exe!KeAcquireInStackQueuedSpinLockAtDpcLevel ntoskrnl.exe!KxWaitForLockOwnerShip [/CODE] CPU#4: [CODE] ntdll.dll!RtlUserThreadStart kernel32.dll!BaseThreadInitThunk qbittorrent.exe!<PDB not found> qbittorrent.exe!<PDB not found> qbittorrent.exe!<PDB not found> qbittorrent.exe!<PDB not found> qbittorrent.exe!<PDB not found> qbittorrent.exe!<PDB not found> qbittorrent.exe!<PDB not found> qbittorrent.exe!<PDB not found> qbittorrent.exe!<PDB not found> qbittorrent.exe!<PDB not found> qbittorrent.exe!<PDB not found> qbittorrent.exe!<PDB not found> qbittorrent.exe!<PDB not found> qbittorrent.exe!<PDB not found> qbittorrent.exe!<PDB not found> qbittorrent.exe!<PDB not found> ws2_32.dll!WSASendTo mswsock.dll!WSPSendTo ntdll.dll!ZwDeviceIoControlFile ntoskrnl.exe!KiSystemServiceCopyEnd ntoskrnl.exe!NtDeviceIoControlFile ntoskrnl.exe!IopXxxControlFile afd.sys!AfdFastIoDeviceControl afd.sys!AfdFastDatagramSend tcpip.sys!UdpTlProviderSendMessages ntoskrnl.exe!KeExpandKernelStackAndCalloutInternal tcpip.sys!UdpTlProviderSendMessagesCalloutRoutine tcpip.sys!UdpSendMessages tcpip.sys!IppJoinPath tcpip.sys!IppFindOrCreatePath ntoskrnl.exe!KeAcquireInStackQueuedSpinLockAtDpcLevel ntoskrnl.exe!KxWaitForLockOwnerShip [/CODE] CPU#0: [CODE] ntoskrnl.exe!KiStartSystemThread ntoskrnl.exe!PspSystemThreadStartup ndis.sys!ndisReceiveWorkerThread ndis.sys!ndisQueuedMiniportDpcWorkItem rt640x64.sys!<PDB not found> rt640x64.sys!<PDB not found> ndis.sys!NdisMIndicateReceiveNetBufferLists ndis.sys!ndisCallReceiveHandler ndis.sys!ndisMTopReceiveNetBufferLists ndis.sys!ndisMIndicateNetBufferListsToOpen tcpip.sys!FlReceiveNetBufferListChain ntoskrnl.exe!KeExpandKernelStackAndCalloutInternal tcpip.sys!FlReceiveNetBufferListChainCalloutRoutine tcpip.sys!IpFlcReceivePreValidatedPackets tcpip.sys!IppFlcReceivePacketsCore tcpip.sys!IppDispatchReceivePacketHelper ntoskrnl.exe!KeAcquireInStackQueuedSpinLockAtDpcLevel ntoskrnl.exe!KxWaitForLockOwnerShip [/CODE] CPU#2: [CODE] ntoskrnl.exe!KiStartSystemThread ntoskrnl.exe!PspSystemThreadStartup ndis.sys!ndisReceiveWorkerThread ndis.sys!ndisQueuedMiniportDpcWorkItem rt640x64.sys!<PDB not found> rt640x64.sys!<PDB not found> rt640x64.sys!<PDB not found> rt640x64.sys!<PDB not found> ndis.sys!NdisMIndicateReceiveNetBufferLists ndis.sys!ndisCallReceiveHandler ndis.sys!ndisMTopReceiveNetBufferLists ndis.sys!ndisMIndicateNetBufferListsToOpen tcpip.sys!FlReceiveNetBufferListChain ntoskrnl.exe!KeExpandKernelStackAndCalloutInternal tcpip.sys!FlReceiveNetBufferListChainCalloutRoutine tcpip.sys!FlpReceiveNonPreValidatedNetBufferListChain tcpip.sys!IppFlcReceivePacketsCore tcpip.sys!IppDispatchReceivePacketHelper ntoskrnl.exe!KeAcquireInStackQueuedSpinLockAtDpcLevel ntoskrnl.exe!KxWaitForLockOwnerShip [/CODE] I have captured a second trace in which only three cores seem to be occupied by [B]ntoskrnl.exe!KxWaitForLockOwnerShip[/B]. I'm still looking into it. [/QUOTE]

Verification