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High DPC Latency or pagefaults - Fresh Install - USBPORT.SYS and others.

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#1 hoplol


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Posted 30 May 2016 - 01:42 AM

Hi, I just updated from windows 7 to 10, and then formatted and installed update 1511 of windows 10. Also had no issues with dpc latency while using windows 7. I've tried everything and haven't been able to resolve this so any help is much appreciated, thanks.



Your system appears to be suitable for handling real-time audio and other tasks without dropouts. 
LatencyMon has been analyzing your system for 0:06:06 (h:mm:ss) on all processors.

Computer name: DESKTOP-LBCJT64
OS version: Windows 8 , 6.2, build: 9200 (x64)
Hardware: P5E-VM HDMI, , ASUSTeK Computer INC.
CPU: GenuineIntel Intel® Core™2 Quad CPU Q9450 @ 2.66GHz
Logical processors: 4
Processor groups: 1
RAM: 4095 MB total

Reported CPU speed: 320 MHz
Measured CPU speed: 1 MHz (approx.)

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.

WARNING: the CPU speed that was measured is only a fraction of the CPU speed reported. Your CPUs may be throttled back due to variable speed settings and thermal issues. It is suggested that you run a utility which reports your actual CPU frequency and temperature. 

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): 439.056298
Average measured interrupt to process latency (µs): 3.854942

Highest measured interrupt to DPC latency (µs): 429.775953
Average measured interrupt to DPC latency (µs): 1.350544

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): 60.580
Driver with highest ISR routine execution time: USBPORT.SYS - USB 1.1 & 2.0 Port Driver, Microsoft Corporation

Highest reported total ISR routine time (%): 0.040874
Driver with highest ISR total time: ataport.SYS - ATAPI Driver Extension, Microsoft Corporation

Total time spent in ISRs (%) 0.080296

ISR count (execution time <250 µs): 366421
ISR count (execution time 250-500 µs): 0
ISR count (execution time 500-999 µs): 0
ISR count (execution time 1000-1999 µs): 0
ISR count (execution time 2000-3999 µs): 0
ISR count (execution time >=4000 µs): 0

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): 256.5150
Driver with highest DPC routine execution time: ndis.sys - Network Driver Interface Specification (NDIS), Microsoft Corporation

Highest reported total DPC routine time (%): 0.067026
Driver with highest DPC total execution time: ataport.SYS - ATAPI Driver Extension, Microsoft Corporation

Total time spent in DPCs (%) 0.365580

DPC count (execution time <250 µs): 966716
DPC count (execution time 250-500 µs): 0
DPC count (execution time 500-999 µs): 2
DPC count (execution time 1000-1999 µs): 0
DPC count (execution time 2000-3999 µs): 0
DPC count (execution time >=4000 µs): 0

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: chrome.exe

Total number of hard pagefaults 9667
Hard pagefault count of hardest hit process: 6185
Highest hard pagefault resolution time (µs): 2382318.45250
Total time spent in hard pagefaults (%): 9.162231
Number of processes hit: 30

CPU 0 Interrupt cycle time (s): 8.410665
CPU 0 ISR highest execution time (µs): 60.580
CPU 0 ISR total execution time (s): 1.078995
CPU 0 ISR count: 333364
CPU 0 DPC highest execution time (µs): 255.170
CPU 0 DPC total execution time (s): 4.789084
CPU 0 DPC count: 902126
CPU 1 Interrupt cycle time (s): 1.546614
CPU 1 ISR highest execution time (µs): 33.03250
CPU 1 ISR total execution time (s): 0.092660
CPU 1 ISR count: 31685
CPU 1 DPC highest execution time (µs): 256.5150
CPU 1 DPC total execution time (s): 0.313617
CPU 1 DPC count: 33995
CPU 2 Interrupt cycle time (s): 1.264148
CPU 2 ISR highest execution time (µs): 15.420
CPU 2 ISR total execution time (s): 0.003562
CPU 2 ISR count: 1196
CPU 2 DPC highest execution time (µs): 116.77250
CPU 2 DPC total execution time (s): 0.129576
CPU 2 DPC count: 16115
CPU 3 Interrupt cycle time (s): 1.237651
CPU 3 ISR highest execution time (µs): 10.80
CPU 3 ISR total execution time (s): 0.000670
CPU 3 ISR count: 176
CPU 3 DPC highest execution time (µs): 141.45750
CPU 3 DPC total execution time (s): 0.121416
CPU 3 DPC count: 14482

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#2 usasma


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Posted 30 May 2016 - 06:14 PM

Here's the advice from LatencyMonitor for hard pagefaults.  I must admit that most of it is beyond my understanding:


  • Hard pagefaults: how to proceed the investigation

    We believe that hard pagefaults are the most common cause of audio dropouts. The effect of a program hitting hard pagefaults while playing audio is usually dramatic. One problem with pagefaults is that they often come in groups so that a row of pagefault causes interruption of the audio stream. Another problem with them is that unlike ISRs and DPCs, putting in more processors into a system will not help you to avoid them. Page faults need to get resolved immediately and any thread that hits them is suspended until the pagefault is resolved. Hitting a hard pagefault on a page file or memory mapped file that is backed on a drive that is spun down because of a power feature may interrupt a program for several seconds until it can proceed.

    If hard pagefaults are reported but no high DPC and ISR execution times you should investigate if these are the cause of audio dropouts. The difficulty with pagefaults is that they are common to occur so it's hard to find out if they are the cause of audio dropouts and stutter. In order to find out if pagefaults are the cultprit you need to know that the pagefault occured in the process responsible for producing audio and also while it was producing audio.

    To verify that the hard pagefault occured in your audio program, take the following steps:

  • Stop the monitor by clicking the stop button
  • Click the Processes tab
  • Now click on the Number of pagefaults column so the view gets sorted
  • Now look for the process name of the audio application that was running and see if it was hit

    Hard pagefaults should only be considered a problem if you can hear they are actually interrupting the audio stream. It is common for any program which uses a lot of memory to hit hard pagefaults. By observing the Processes view while audio is playing you can find out if hard pagefaults are being hit while audio is playing. If you found out that pagefaults are the cause of audio dropouts you should read the next section on how to avoid them.

    How to avoid hard pagefaults

    If you have concluded that hard pagefaults are the cause of audio dropouts, you can do any of the following to resolve the problems:

  • Close down unnecessary applications which consume a lot of RAM
  • Close down unnecessary service applications which consume a lot of RAM (the Search Indexer service is notorious)
  • Increase the amount of RAM in your system
  • Increase the working set of the audio application, only an option if you are the author of the software.
  • Make sure audio data is paged-in (resident). Pages of memory are swapped out based on their use counts. If you use Windows for live playing, do a silent run of your software synthesizer. After changing patch on a sampler, touch all keys so that all memory it uses is paged-in to avoid embarrasing scenes.
  • Disable the pagefile altogether. You can disable the pagefile by right-clicking My Computer and selecting Advanced System Settings->Advanced->Performance Settings->Advanced->Virtual memory->Change. Note that if you have no pagefile, the system can run out of memory if not enough memory is available. Also the system will no longer create crash dump files in case of a system crash.



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#3 hoplol

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Posted 31 May 2016 - 04:02 PM

Hey im going to considered this closed. Windows 10 doesn't like my two dvd drivers so I disconnected them and everything is much better now, thanks.

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