Question LatencyMon: high "Highest measured interrupt to process latency" without high ISR or DPC numbers ?

[AdventDude]

Hi. I have a Dell Precision 3420 SFF Intel i7 Desktop PC on which I'm running REAPER and have been experiencing intermittent brief audio dropouts. Some days I can spend an hour or two without any problems but the problem will show up one or more times on other days. After performing a complete system update yesterday, I noticed the problem happening more often than normal today so I ran LatencyMon (Home Edition) while working and, after one dropout, I found that the only metric that showed any problematic number was "Highest measured interrupt to process latency"--with the specific numbers from a 15.5-minute test reading:

• Current measured interrupt to process latency (µs): 130.60 [green]
• Highest measured interrupt to process latency (µs): 10190.80 [red]
• Highest reported ISR routine execution time (µs): 79.617371 (Wdf01000.sys) [green]
• Highest reported DPC routine execution time (µs): 392.928404 (ndis.sys) [green]

Though not an advanced user, I checked a few of the BIOS settings that I thought might be relevant as well. They are currently as follows (untouched from factory defaults I assume, as I've never changed anything):

Enable Intel SpeedStep	enabled
C states	enabled
Enable CPUID Limit	disabled
Enable Intel TurboBoost	enabled
HyperThread control	enabled

I've done a lot of searching but haven't found another example of anyone with similar issues running LatencyMon where problems were exclusive to "Highest measured interrupt to process latency"--and the vast majority seemed to relate to laptops with issues that often point to power management issues. (I have a Dell laptop with a much more serious latency problem that relates to ACPI.sys, but am only focused on getting the desktop in question working properly.)

Any guidance in how to effectively resolve this issue would be greatly appreciated. Thanks a lot! -Alan

 

[Colif]

Latencymon
when you run it, look on the drivers tab... the front page really doesn't show you much.
GPU drivers often at top of usage but this is normal.

only clue you offer is ndis.sys. its the network driver interface specification. Its a windows driver that talks to network drivers... so try updating LAN/Wifi drivers as a lot of times they are the cause of latency.

if you use wifi, sometimes disabling Ethernet can fix it.

 

[AdventDude]

Latencymon
when you run it, look on the drivers tab... the front page really doesn't show you much.
GPU drivers often at top of usage but this is normal.

only clue you offer is ndis.sys. its the network driver interface specification. Its a windows driver that talks to network drivers... so try updating LAN/Wifi drivers as a lot of times they are the cause of latency.

Thanks for your kind reply. I'll run LatencyMon again and will investigate the Drivers time the next time around. I usually keep this PC offline while recording, but it is normally connected to an external Wi-Fi adapter at all other times (as was the case yesterday). I don't use the internal Wi-Fi and, perhaps I should just disable it anyway--and will look to see if I can find an updated driver for the Ethernet port as well.

Best wishes and, again, much appreciated. -Alan

 

[Colif]

what external wifi adapter is it? I could see if newer drivers for it.

 

[AdventDude]

what external wifi adapter is it? I could see if newer drivers for it.

Thanks for asking. It's actually a Wi-Fi extender that connects to the PC over wired 100 Mpbs Ethernet. As the PC doesn't directly interface with this extender (and I still have these intermittent problems when the wireless extender is unplugged from its power source), I don't think it's likely to be the issue. That being said, the Wi-Fi extender in question is a BrosTrend Model E1 (AC1200).

On a related note, I updated the driver for the PC's (hardwired) Ethernet port this morning and ran another test for over an hour without any issues. I have previously experienced full sessions on days where the audio problem never occurred and others where it came back, though, so I'll keep testing and will update the post as soon as I experience at least one more audio dropout.

Best wishes and thanks again for your help.

 

[Colif]

Thanks for asking. It's actually a Wi-Fi extender that connects to the PC over wired 100 Mpbs Ethernet. As the PC doesn't directly interface with this extender (and I still have these intermittent problems when the wireless extender is unplugged from its power source), I don't think it's likely to be the issue. That being said, the Wi-Fi extender in question is a BrosTrend Model E1 (AC1200).

okay. i get it. But that means it does use the internal wifi as it has to, to contact the extender. It is probably not a problem though.

If you don't use Ethernet on it at all, disabling the adapter might work as well. I seen it is a known fix.

 

[AdventDude]

okay. i get it. But that means it does use the internal wifi as it has to, to contact the extender. It is probably not a problem though.

If you don't use Ethernet on it at all, disabling the adapter might work as well. I seen it is a known fix.

Thanks a lot for the additional feedback. Apologies for not being sufficiently clear, but the internal Wi-Fi of the PC is unused and the 100 Mpbs Ethernet port is hardwired to the external Wi-Fi extender in question. As such, the Ethernet port is the only network port that's actually in use.

I couldn't replicate the problem for a couple of days, but know that loading up one of my piano sample libraries (using UVI Workstation) often causes problems, so I did that today and ended up taking a big hit with another super-high "Highest measured interrupt to process latency" of 9766.50 µs, but this time I also got a "Highest DPC routine execution time" hit with "dxgkrnl.sys - DirectX Graphics Kernel, Microsoft Corporation" at 1346.983568 µs. I'll post in the full LatencyMon report below as well for more detail.

I hope this additional information is helpful and, once again, very much appreciate the help in troubleshooting (and, hopefully, resolving) this problem. Thanks a lot and best wishes. -Alan

NEW LATENCYMON REPORT FOLLOWS:

_________________________________________________________________________________________________________
CONCLUSION
_________________________________________________________________________________________________________
Your system appears to be having trouble handling real-time audio and other tasks. You are likely to experience buffer underruns appearing as drop outs, clicks or pops. One or more DPC routines that belong to a driver running in your system appear to be executing for too long. One problem may be related to power management, disable CPU throttling settings in Control Panel and BIOS setup. Check for BIOS updates.
LatencyMon has been analyzing your system for 0:34:24 (h:mm:ss) on all processors.


_________________________________________________________________________________________________________
SYSTEM INFORMATION
_________________________________________________________________________________________________________
Computer name: STUDIO-2022
OS version: Windows 10, 10.0, version 2009, build: 19045 (x64)
Hardware: Precision Tower 3420, Dell Inc.
BIOS: 2.30.0
CPU: GenuineIntel Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz
Logical processors: 8
Processor groups: 1
Processor group size: 8
RAM: 32659 MB total


_________________________________________________________________________________________________________
CPU SPEED
_________________________________________________________________________________________________________
Reported CPU speed (WMI): 3408 MHz
Reported CPU speed (registry): 3408 MHz

Note: reported execution times may be calculated based on a fixed reported CPU speed. Disable variable speed settings like Intel Speed Step and AMD Cool N Quiet in the BIOS setup for more accurate results.


_________________________________________________________________________________________________________
MEASURED INTERRUPT TO USER PROCESS LATENCIES
_________________________________________________________________________________________________________
The interrupt to process latency reflects the measured interval that a usermode process needed to respond to a hardware request from the moment the interrupt service routine started execution. This includes the scheduling and execution of a DPC routine, the signaling of an event and the waking up of a usermode thread from an idle wait state in response to that event.

Highest measured interrupt to process latency (µs): 9766.50
Average measured interrupt to process latency (µs): 7.990981

Highest measured interrupt to DPC latency (µs): 9762.10
Average measured interrupt to DPC latency (µs): 3.183713


_________________________________________________________________________________________________________
REPORTED ISRs
_________________________________________________________________________________________________________
Interrupt service routines are routines installed by the OS and device drivers that execute in response to a hardware interrupt signal.

Highest ISR routine execution time (µs): 85.752347
Driver with highest ISR routine execution time: Wdf01000.sys - Kernel Mode Driver Framework Runtime, Microsoft Corporation

Highest reported total ISR routine time (%): 0.004983
Driver with highest ISR total time: Wdf01000.sys - Kernel Mode Driver Framework Runtime, Microsoft Corporation

Total time spent in ISRs (%) 0.004983

ISR count (execution time <250 µs): 816058
ISR count (execution time 250-500 µs): 0
ISR count (execution time 500-1000 µs): 0
ISR count (execution time 1000-2000 µs): 0
ISR count (execution time 2000-4000 µs): 0
ISR count (execution time >=4000 µs): 0


_________________________________________________________________________________________________________
REPORTED DPCs
_________________________________________________________________________________________________________
DPC routines are part of the interrupt servicing dispatch mechanism and disable the possibility for a process to utilize the CPU while it is interrupted until the DPC has finished execution.

Highest DPC routine execution time (µs): 1346.983568
Driver with highest DPC routine execution time: dxgkrnl.sys - DirectX Graphics Kernel, Microsoft Corporation

Highest reported total DPC routine time (%): 0.145579
Driver with highest DPC total execution time: Wdf01000.sys - Kernel Mode Driver Framework Runtime, Microsoft Corporation

Total time spent in DPCs (%) 0.218402

DPC count (execution time <250 µs): 3193086
DPC count (execution time 250-500 µs): 0
DPC count (execution time 500-10000 µs): 253
DPC count (execution time 1000-2000 µs): 1
DPC count (execution time 2000-4000 µs): 0
DPC count (execution time >=4000 µs): 0


_________________________________________________________________________________________________________
REPORTED HARD PAGEFAULTS
_________________________________________________________________________________________________________
Hard pagefaults are events that get triggered by making use of virtual memory that is not resident in RAM but backed by a memory mapped file on disk. The process of resolving the hard pagefault requires reading in the memory from disk while the process is interrupted and blocked from execution.

NOTE: some processes were hit by hard pagefaults. If these were programs producing audio, they are likely to interrupt the audio stream resulting in dropouts, clicks and pops. Check the Processes tab to see which programs were hit.

Process with highest pagefault count: msmpeng.exe

Total number of hard pagefaults 18243
Hard pagefault count of hardest hit process: 8823
Number of processes hit: 50


_________________________________________________________________________________________________________
PER CPU DATA
_________________________________________________________________________________________________________
CPU 0 Interrupt cycle time (s): 71.491565
CPU 0 ISR highest execution time (µs): 85.752347
CPU 0 ISR total execution time (s): 0.806848
CPU 0 ISR count: 805487
CPU 0 DPC highest execution time (µs): 1346.983568
CPU 0 DPC total execution time (s): 31.580847
CPU 0 DPC count: 2076023
_________________________________________________________________________________________________________
CPU 1 Interrupt cycle time (s): 7.558680
CPU 1 ISR highest execution time (µs): 35.763498
CPU 1 ISR total execution time (s): 0.016055
CPU 1 ISR count: 10571
CPU 1 DPC highest execution time (µs): 543.980047
CPU 1 DPC total execution time (s): 0.739651
CPU 1 DPC count: 74950
_________________________________________________________________________________________________________
CPU 2 Interrupt cycle time (s): 11.210540
CPU 2 ISR highest execution time (µs): 0.0
CPU 2 ISR total execution time (s): 0.0
CPU 2 ISR count: 0
CPU 2 DPC highest execution time (µs): 338.609742
CPU 2 DPC total execution time (s): 1.096618
CPU 2 DPC count: 384713
_________________________________________________________________________________________________________
CPU 3 Interrupt cycle time (s): 7.166607
CPU 3 ISR highest execution time (µs): 0.0
CPU 3 ISR total execution time (s): 0.0
CPU 3 ISR count: 0
CPU 3 DPC highest execution time (µs): 255.191315
CPU 3 DPC total execution time (s): 0.219938
CPU 3 DPC count: 48191
_________________________________________________________________________________________________________
CPU 4 Interrupt cycle time (s): 12.515571
CPU 4 ISR highest execution time (µs): 0.0
CPU 4 ISR total execution time (s): 0.0
CPU 4 ISR count: 0
CPU 4 DPC highest execution time (µs): 245.626174
CPU 4 DPC total execution time (s): 0.957145
CPU 4 DPC count: 307280
_________________________________________________________________________________________________________
CPU 5 Interrupt cycle time (s): 6.942733
CPU 5 ISR highest execution time (µs): 0.0
CPU 5 ISR total execution time (s): 0.0
CPU 5 ISR count: 0
CPU 5 DPC highest execution time (µs): 311.603873
CPU 5 DPC total execution time (s): 0.236189
CPU 5 DPC count: 45698
_________________________________________________________________________________________________________
CPU 6 Interrupt cycle time (s): 11.45690
CPU 6 ISR highest execution time (µs): 0.0
CPU 6 ISR total execution time (s): 0.0
CPU 6 ISR count: 0
CPU 6 DPC highest execution time (µs): 296.004695
CPU 6 DPC total execution time (s): 1.062609
CPU 6 DPC count: 227084
_________________________________________________________________________________________________________
CPU 7 Interrupt cycle time (s): 6.259122
CPU 7 ISR highest execution time (µs): 0.0
CPU 7 ISR total execution time (s): 0.0
CPU 7 ISR count: 0
CPU 7 DPC highest execution time (µs): 210.664319
CPU 7 DPC total execution time (s): 0.177424
CPU 7 DPC count: 29401
_________________________________________________________________________________________________________

 

[Colif]

when you run it, look on the drivers tab... the front page really doesn't show you much.

screenshots of it are more useful as well. Might offer a clue.

Dell Precision 3420 SFF Intel i7 Desktop PC on which I'm running REAPER

what is reaper? I should have asked (might not help, could just be curiosity)
Have you checked to see if any new drivers here:
https://www.dell.com/support/home/en-au/product-support/product/precision-t3420-workstation/drivers

OS version: Windows 10, 10.0, version 2009, build: 19045 (x64)

that seems odd... version 2009? 19045 = Version 22H2
could just be the program, wonder what it thinks Win 11 is.

 

[AdventDude]

screenshots of it are more useful as well. Might offer a clue.

Thanks for the advice. I'm new to the forum and couldn't easily find a way to upload a screenshot (aside from posting it somewhere where I can copy the URL here).

what is reaper? I should have asked (might not help, could just be curiosity)
Have you checked to see if any new drivers here:
https://www.dell.com/support/home/en-au/product-support/product/precision-t3420-workstation/drivers

REAPER is a DAW (digital audio workstation):

REAPER | Audio Production Without Limits

I appreciate the suggestion for checking the drivers and actually updated everything I could find in this regard earlier today. (It's hard to tell if I reinstalled updates that were already installed in some cases, but completed the two that Dell recommended as well.) Unfortunately, though I didn't have a chance to run LatencyMon afterward, I experienced a similar dropout early on--so I'm pretty sure the issue remains. I'll try to do some more thorough testing as I work further in the studio throughout the week, though.

that seems odd... version 2009? 19045 = Version 22H2
could just be the program, wonder what it thinks Win 11 is.

I'm not sure about this, but know that we just performed a full Windows 10 update last week.

Best wishes and thanks again for your help.

 

[Colif]

Thanks for the advice. I'm new to the forum and couldn't easily find a way to upload a screenshot (aside from posting it somewhere where I can copy the URL here).

uploading to imgur or another image site and posting links here is only way really.

it thinks my windows 11 is 2009 as well so its just wrong in general.

 

[AdventDude]

Hi again. I wanted to spend a couple of days testing and ended up having problems on two consecutive days and disabled both hyperthreading and C states in BIOS in between. The LatencyMon reports differ between days, but the PC is still having intermittent (though almost daily) DPC latency issues I'm really hoping to fix. I'll paste in the detailed LatencyMon reports below, but am also now wondering if the large number of page faults may also be problematic in some way (and I have 32 GB on the PC, with very little going on at the time of testing this week).

Again, any guidance would be greatly appreciated. A big thank-you to Colif for the engagement and help thus far too.

-----

JUNE 13 LATENCYMON RESULTS:

_________________________________________________________________________________________________________
CONCLUSION
_________________________________________________________________________________________________________
Your system appears to be having trouble handling real-time audio and other tasks. You are likely to experience buffer underruns appearing as drop outs, clicks or pops. One or more DPC routines that belong to a driver running in your system appear to be executing for too long. At least one detected problem appears to be network related. In case you are using a WLAN adapter, try disabling it to get better results. One problem may be related to power management, disable CPU throttling settings in Control Panel and BIOS setup. Check for BIOS updates.
LatencyMon has been analyzing your system for 0:17:02 (h:mm:ss) on all processors.


_________________________________________________________________________________________________________
SYSTEM INFORMATION
_________________________________________________________________________________________________________
Computer name: STUDIO-2022
OS version: Windows 10, 10.0, version 2009, build: 19045 (x64)
Hardware: Precision Tower 3420, Dell Inc.
BIOS: 2.30.0
CPU: GenuineIntel Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz
Logical processors: 8
Processor groups: 1
Processor group size: 8
RAM: 32659 MB total


_________________________________________________________________________________________________________
CPU SPEED
_________________________________________________________________________________________________________
Reported CPU speed (WMI): 3408 MHz
Reported CPU speed (registry): 3408 MHz

Note: reported execution times may be calculated based on a fixed reported CPU speed. Disable variable speed settings like Intel Speed Step and AMD Cool N Quiet in the BIOS setup for more accurate results.


_________________________________________________________________________________________________________
MEASURED INTERRUPT TO USER PROCESS LATENCIES
_________________________________________________________________________________________________________
The interrupt to process latency reflects the measured interval that a usermode process needed to respond to a hardware request from the moment the interrupt service routine started execution. This includes the scheduling and execution of a DPC routine, the signaling of an event and the waking up of a usermode thread from an idle wait state in response to that event.

Highest measured interrupt to process latency (µs): 10102.50
Average measured interrupt to process latency (µs): 6.653254

Highest measured interrupt to DPC latency (µs): 10097.80
Average measured interrupt to DPC latency (µs): 2.194844


_________________________________________________________________________________________________________
REPORTED ISRs
_________________________________________________________________________________________________________
Interrupt service routines are routines installed by the OS and device drivers that execute in response to a hardware interrupt signal.

Highest ISR routine execution time (µs): 825.882042
Driver with highest ISR routine execution time: ACPI.sys - ACPI Driver for NT, Microsoft Corporation

Highest reported total ISR routine time (%): 0.011092
Driver with highest ISR total time: Wdf01000.sys - Kernel Mode Driver Framework Runtime, Microsoft Corporation

Total time spent in ISRs (%) 0.011255

ISR count (execution time <250 µs): 1033808
ISR count (execution time 250-500 µs): 0
ISR count (execution time 500-1000 µs): 16
ISR count (execution time 1000-2000 µs): 0
ISR count (execution time 2000-4000 µs): 0
ISR count (execution time >=4000 µs): 0


_________________________________________________________________________________________________________
REPORTED DPCs
_________________________________________________________________________________________________________
DPC routines are part of the interrupt servicing dispatch mechanism and disable the possibility for a process to utilize the CPU while it is interrupted until the DPC has finished execution.

Highest DPC routine execution time (µs): 1990.850352
Driver with highest DPC routine execution time: Wdf01000.sys - Kernel Mode Driver Framework Runtime, Microsoft Corporation

Highest reported total DPC routine time (%): 0.349023
Driver with highest DPC total execution time: Wdf01000.sys - Kernel Mode Driver Framework Runtime, Microsoft Corporation

Total time spent in DPCs (%) 0.448431

DPC count (execution time <250 µs): 2882212
DPC count (execution time 250-500 µs): 0
DPC count (execution time 500-10000 µs): 67
DPC count (execution time 1000-2000 µs): 2
DPC count (execution time 2000-4000 µs): 0
DPC count (execution time >=4000 µs): 0


_________________________________________________________________________________________________________
REPORTED HARD PAGEFAULTS
_________________________________________________________________________________________________________
Hard pagefaults are events that get triggered by making use of virtual memory that is not resident in RAM but backed by a memory mapped file on disk. The process of resolving the hard pagefault requires reading in the memory from disk while the process is interrupted and blocked from execution.

NOTE: some processes were hit by hard pagefaults. If these were programs producing audio, they are likely to interrupt the audio stream resulting in dropouts, clicks and pops. Check the Processes tab to see which programs were hit.

Process with highest pagefault count: msmpeng.exe

Total number of hard pagefaults 24218
Hard pagefault count of hardest hit process: 14387
Number of processes hit: 44


_________________________________________________________________________________________________________
PER CPU DATA
_________________________________________________________________________________________________________
CPU 0 Interrupt cycle time (s): 54.594492
CPU 0 ISR highest execution time (µs): 825.882042
CPU 0 ISR total execution time (s): 0.918685
CPU 0 ISR count: 1031441
CPU 0 DPC highest execution time (µs): 1990.850352
CPU 0 DPC total execution time (s): 33.652796
CPU 0 DPC count: 2337601
_________________________________________________________________________________________________________
CPU 1 Interrupt cycle time (s): 13.709195
CPU 1 ISR highest execution time (µs): 16.096831
CPU 1 ISR total execution time (s): 0.001840
CPU 1 ISR count: 2383
CPU 1 DPC highest execution time (µs): 452.193662
CPU 1 DPC total execution time (s): 1.592082
CPU 1 DPC count: 259020
_________________________________________________________________________________________________________
CPU 2 Interrupt cycle time (s): 8.050919
CPU 2 ISR highest execution time (µs): 0.0
CPU 2 ISR total execution time (s): 0.0
CPU 2 ISR count: 0
CPU 2 DPC highest execution time (µs): 307.117958
CPU 2 DPC total execution time (s): 0.489876
CPU 2 DPC count: 105416
_________________________________________________________________________________________________________
CPU 3 Interrupt cycle time (s): 6.792013
CPU 3 ISR highest execution time (µs): 0.0
CPU 3 ISR total execution time (s): 0.0
CPU 3 ISR count: 0
CPU 3 DPC highest execution time (µs): 106.335094
CPU 3 DPC total execution time (s): 0.177059
CPU 3 DPC count: 40140
_________________________________________________________________________________________________________
CPU 4 Interrupt cycle time (s): 7.106604
CPU 4 ISR highest execution time (µs): 0.0
CPU 4 ISR total execution time (s): 0.0
CPU 4 ISR count: 0
CPU 4 DPC highest execution time (µs): 228.471244
CPU 4 DPC total execution time (s): 0.237008
CPU 4 DPC count: 44112
_________________________________________________________________________________________________________
CPU 5 Interrupt cycle time (s): 6.433217
CPU 5 ISR highest execution time (µs): 0.0
CPU 5 ISR total execution time (s): 0.0
CPU 5 ISR count: 0
CPU 5 DPC highest execution time (µs): 96.559859
CPU 5 DPC total execution time (s): 0.128517
CPU 5 DPC count: 22601
_________________________________________________________________________________________________________
CPU 6 Interrupt cycle time (s): 6.691198
CPU 6 ISR highest execution time (µs): 0.0
CPU 6 ISR total execution time (s): 0.0
CPU 6 ISR count: 0
CPU 6 DPC highest execution time (µs): 207.277582
CPU 6 DPC total execution time (s): 0.232455
CPU 6 DPC count: 40101
_________________________________________________________________________________________________________
CPU 7 Interrupt cycle time (s): 7.176603
CPU 7 ISR highest execution time (µs): 0.0
CPU 7 ISR total execution time (s): 0.0
CPU 7 ISR count: 0
CPU 7 DPC highest execution time (µs): 121.605047
CPU 7 DPC total execution time (s): 0.165118
CPU 7 DPC count: 33290
_________________________________________________________________________________________________________

-----

JUNE 14 LATENCYMON RESULTS:

_________________________________________________________________________________________________________
CONCLUSION
_________________________________________________________________________________________________________
Your system appears to be having trouble handling real-time audio and other tasks. You are likely to experience buffer underruns appearing as drop outs, clicks or pops. One or more DPC routines that belong to a driver running in your system appear to be executing for too long. One problem may be related to power management, disable CPU throttling settings in Control Panel and BIOS setup. Check for BIOS updates.
LatencyMon has been analyzing your system for 0:26:12 (h:mm:ss) on all processors.


_________________________________________________________________________________________________________
SYSTEM INFORMATION
_________________________________________________________________________________________________________
Computer name: STUDIO-2022
OS version: Windows 10, 10.0, version 2009, build: 19045 (x64)
Hardware: Precision Tower 3420, Dell Inc.
BIOS: 2.30.0
CPU: GenuineIntel Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz
Logical processors: 4
Processor groups: 1
Processor group size: 4
RAM: 32659 MB total


_________________________________________________________________________________________________________
CPU SPEED
_________________________________________________________________________________________________________
Reported CPU speed (WMI): 3408 MHz
Reported CPU speed (registry): 3408 MHz

Note: reported execution times may be calculated based on a fixed reported CPU speed. Disable variable speed settings like Intel Speed Step and AMD Cool N Quiet in the BIOS setup for more accurate results.


_________________________________________________________________________________________________________
MEASURED INTERRUPT TO USER PROCESS LATENCIES
_________________________________________________________________________________________________________
The interrupt to process latency reflects the measured interval that a usermode process needed to respond to a hardware request from the moment the interrupt service routine started execution. This includes the scheduling and execution of a DPC routine, the signaling of an event and the waking up of a usermode thread from an idle wait state in response to that event.

Highest measured interrupt to process latency (µs): 9675.60
Average measured interrupt to process latency (µs): 3.635105

Highest measured interrupt to DPC latency (µs): 220.60
Average measured interrupt to DPC latency (µs): 1.000120


_________________________________________________________________________________________________________
REPORTED ISRs
_________________________________________________________________________________________________________
Interrupt service routines are routines installed by the OS and device drivers that execute in response to a hardware interrupt signal.

Highest ISR routine execution time (µs): 17.840962
Driver with highest ISR routine execution time: Wdf01000.sys - Kernel Mode Driver Framework Runtime, Microsoft Corporation

Highest reported total ISR routine time (%): 0.012216
Driver with highest ISR total time: Wdf01000.sys - Kernel Mode Driver Framework Runtime, Microsoft Corporation

Total time spent in ISRs (%) 0.012216

ISR count (execution time <250 µs): 1636457
ISR count (execution time 250-500 µs): 0
ISR count (execution time 500-1000 µs): 0
ISR count (execution time 1000-2000 µs): 0
ISR count (execution time 2000-4000 µs): 0
ISR count (execution time >=4000 µs): 0


_________________________________________________________________________________________________________
REPORTED DPCs
_________________________________________________________________________________________________________
DPC routines are part of the interrupt servicing dispatch mechanism and disable the possibility for a process to utilize the CPU while it is interrupted until the DPC has finished execution.

Highest DPC routine execution time (µs): 1806.400822
Driver with highest DPC routine execution time: storport.sys - Microsoft Storage Port Driver, Microsoft Corporation

Highest reported total DPC routine time (%): 0.338582
Driver with highest DPC total execution time: Wdf01000.sys - Kernel Mode Driver Framework Runtime, Microsoft Corporation

Total time spent in DPCs (%) 0.561417

DPC count (execution time <250 µs): 5754590
DPC count (execution time 250-500 µs): 0
DPC count (execution time 500-10000 µs): 7
DPC count (execution time 1000-2000 µs): 2
DPC count (execution time 2000-4000 µs): 0
DPC count (execution time >=4000 µs): 0


_________________________________________________________________________________________________________
REPORTED HARD PAGEFAULTS
_________________________________________________________________________________________________________
Hard pagefaults are events that get triggered by making use of virtual memory that is not resident in RAM but backed by a memory mapped file on disk. The process of resolving the hard pagefault requires reading in the memory from disk while the process is interrupted and blocked from execution.

NOTE: some processes were hit by hard pagefaults. If these were programs producing audio, they are likely to interrupt the audio stream resulting in dropouts, clicks and pops. Check the Processes tab to see which programs were hit.

Process with highest pagefault count: msmpeng.exe

Total number of hard pagefaults 208938
Hard pagefault count of hardest hit process: 161659
Number of processes hit: 71


_________________________________________________________________________________________________________
PER CPU DATA
_________________________________________________________________________________________________________
CPU 0 Interrupt cycle time (s): 54.681377
CPU 0 ISR highest execution time (µs): 17.840962
CPU 0 ISR total execution time (s): 0.759255
CPU 0 ISR count: 1620344
CPU 0 DPC highest execution time (µs): 1806.400822
CPU 0 DPC total execution time (s): 32.348215
CPU 0 DPC count: 5068460
_________________________________________________________________________________________________________
CPU 1 Interrupt cycle time (s): 6.695755
CPU 1 ISR highest execution time (µs): 9.745892
CPU 1 ISR total execution time (s): 0.008936
CPU 1 ISR count: 16113
CPU 1 DPC highest execution time (µs): 360.688380
CPU 1 DPC total execution time (s): 1.726028
CPU 1 DPC count: 339447
_________________________________________________________________________________________________________
CPU 2 Interrupt cycle time (s): 5.563339
CPU 2 ISR highest execution time (µs): 0.0
CPU 2 ISR total execution time (s): 0.0
CPU 2 ISR count: 0
CPU 2 DPC highest execution time (µs): 87.241784
CPU 2 DPC total execution time (s): 0.584335
CPU 2 DPC count: 169857
_________________________________________________________________________________________________________
CPU 3 Interrupt cycle time (s): 5.565502
CPU 3 ISR highest execution time (µs): 0.0
CPU 3 ISR total execution time (s): 0.0
CPU 3 ISR count: 0
CPU 3 DPC highest execution time (µs): 87.194836
CPU 3 DPC total execution time (s): 0.646469
CPU 3 DPC count: 176835
_________________________________________________________________________________________________________

 

[Colif]

Driver with highest DPC routine execution time: storport.sys - Microsoft Storage Port Driver, Microsoft Corporation

Dell Precision 3420 SFF Intel i7 Desktop PC

Do you have ssd or hdd in that?
https://i.dell.com/sites/csdocument...ecision-Tower-3000-Series-3420-Spec-Sheet.pdf

try running this on drives, blue icon - it will auto collect scores it needs

Crystal Dew World

https://www.sysnative.com/forums/threads/high-latency-issues-in-windows-10-storport-sys.27355/

This is how to link images:

Spoiler

go here - https://imgur.com/
you might need to set up a user.

click on New Post which will display next screen where you can select image(s) - hold Ctrl while selecting images in explorer to get multiple

Once uploaded, images will show on the next page

right clicking an image (once its shown its completely uploaded - shows a green label when it does) and choosing open in new tab gives access to the jpg image
to insert this into a post, see instructions below for direct link


To see older uploaded photo, click on username and choose images, will show bottom page or similar

if you click any image on this page it shows as below:

if you click the Image link button on this page above, and then copy paste the link into the Insert, media option in photo below,

it will show as:

https://imgur.com/2YSmewE

if you click it, it opens in imgur

whereas if you copy the Direct link and then use the insert image option, it appears as

if you click it, it opens a bigger picture on another page of forums, and you can use an option at top to go to imgur, make it full screen, save a copy or close image.

The advantage to using the jpg is it can be resized

once its in the thread you can highlight the image

squares will appear on corners allowing you to resize image

If you just copy/paste an image into text block, it will use the Gallery view (1st image)

 

[AdventDude]

Do you have ssd or hdd in that?
https://i.dell.com/sites/csdocument...ecision-Tower-3000-Series-3420-Spec-Sheet.pdf

try running this on drives, blue icon - it will auto collect scores it needs

Crystal Dew World

https://www.sysnative.com/forums/threads/high-latency-issues-in-windows-10-storport-sys.27355/

This is how to link images:

Thanks very much for the follow-up. I have an SSD and have never seen storport.sys come up in LatencyMon except for this one occurrence. I'm still seeing some results where "Highest measure interrupt to process latency" is the only real problem, by the way, but other times a driver will also show up as problematic.

I had pretty good luck with the PC for the rest of the day, but am still wondering if the number of page faults may point to something else as well.

Best wishes and thanks again for your help. -Alan

 

[Colif]

Total number of hard pagefaults 208938
Hard pagefault count of hardest hit process: 161659
Number of processes hit: 71

Page faults happen when CPU needs info out of ram
Hard page faults occur when CPU needs to access info off the storage drive
Both of these are normal actions of windows, but the numbers of them can be clues.

Combined with the storport,sys driver showing up, could just mean you were reading/writing lots of files to the drives or more evidence drives could be cause. Were you doing anything that could have caused lots of drive activity?

how old is ssd? What make/model is it? Most makers have software can run to test drives, make sure they are working.