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Cannot get low latency with USB audio gear
#5
(06-23-2020, 08:40 PM)StuartR Wrote:
(06-23-2020, 12:24 PM)Steven Minzer Wrote: Thanks, StuartR. I ran LatancyMon, but could not  paste a screenshot in a New Reply, my post attempt failing due to an excessive message length error (Is there a link to a tutorial on using forums for meeting. I am entering the red text portion from the screenshot.
——
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 DFC 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 W-LAN 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.
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I read the first three chapters of Glitch Free, the audio and computer for dummies overview. The section comparing the processor to a chef made me sad, since I haven’t gone out to eat for some time. Chapter 4 starts getting into the nuts and bolts of tuning. while I have come across tuning suggestions here and there, it’s good to have a comprehensive treatment of the subject and I will be working my way through it.

I am sorry that I am not able to share more results from LatencyMon, but wanted to send this quick reply out.

Thanks for your help.
The fact that the text in the report is in red indicates your PC, in its current state, isn't capable of handling real-time audio. Please post the text report. Don't use a quoted reply so as not to include all your previous text which is where the posting error is coming from.

Some initial things you'll need to do:

1) Change your PC power plan to maximum.
2)  Disable WiFi and Bluetooth
3) Be sure your PC or laptop, is running on AC power... never on battery.
4) Disable Background apps.
5) Go to ADD/REMOVE programs and uninstall anything you don't need. Since you've had this PC a while I'd guess it's loaded with unnecessary apps, secondary antivirus tools,etc. Clean all this out.
6) Go to the vendor (Sony) site and be sure the latest BIOS and drivers are installed.

You never said what version of Windows you are running?

Then rerun LatencyMon (for at least 5 minutes) and compare the results.
My OS is windows 10 home. I read through Glitch Free, making many changes suggested. I followed the suggestion in the list from StuartR, updating Windows, but I decided not to do a BIOS update yet, as recommended in Glitch Free.
I finally was able to add gear successfully for Reaper/Asio4all (Rearoute) to my profile. Jamkazam complains about it, especially when I create a solo session with frame size settings  under 10 ms, the input and output jitter spiking. 
Running LatencyMon, the red text in  reports have disappeared. But I don’t know what to do with the results. It runs now for about 3 minutes in a suitable for audio state before noting possible problems for audio. I am pasting the LatencyMon report text below.


_________________________________________________________________________________________________________
CONCLUSION
_________________________________________________________________________________________________________
Your system seems to be having difficulty handling real-time audio and other tasks. You may experience drop outs, clicks or pops due to buffer underruns. 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  0:07:07  (h:mmConfuseds) on all processors.


_________________________________________________________________________________________________________
SYSTEM INFORMATION
_________________________________________________________________________________________________________
Computer name:                                        BARBARA-VAIO
OS version:                                           Windows 10 , 10.0, build: 19041 (x64)
Hardware:                                             VGN-NW320F, Sony Corporation, VAIO
CPU:                                                  GenuineIntel Intel® Core™2 Duo CPU T6600 @ 2.20GHz
Logical processors:                                   2
Processor groups:                                     1
RAM:                                                  3935 MB total


_________________________________________________________________________________________________________
CPU SPEED
_________________________________________________________________________________________________________
Reported CPU speed:                                   2193 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.

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. 



_________________________________________________________________________________________________________
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):   465.70
Average measured interrupt to process latency (µs):   7.106197

Highest measured interrupt to DPC latency (µs):       462.20
Average measured interrupt to DPC latency (µs):       2.356204


_________________________________________________________________________________________________________
 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):              42.409941
Driver with highest ISR routine execution time:       USBPORT.SYS - USB 1.1 & 2.0 Port Driver, Microsoft Corporation

Highest reported total ISR routine time (%):          0.003455
Driver with highest ISR total time:                   iaStor.sys - Intel Matrix Storage Manager driver - x64, Intel Corporation

Total time spent in ISRs (%)                          0.008773

ISR count (execution time <250 µs):                   11827
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


_________________________________________________________________________________________________________
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):              1348.676243
Driver with highest DPC routine execution time:       ACPI.sys - ACPI Driver for NT, Microsoft Corporation

Highest reported total DPC routine time (%):          0.024348
Driver with highest DPC total execution time:         ntoskrnl.exe - NT Kernel & System, Microsoft Corporation

Total time spent in DPCs (%)                          0.080587

DPC count (execution time <250 µs):                   115324
DPC count (execution time 250-500 µs):                0
DPC count (execution time 500-999 µs):                21
DPC count (execution time 1000-1999 µs):              5
DPC count (execution time 2000-3999 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:                 nortonsecurity.exe

Total number of hard pagefaults                       216
Hard pagefault count of hardest hit process:          64
Number of processes hit:                              14


_________________________________________________________________________________________________________
 PER CPU DATA
_________________________________________________________________________________________________________
CPU 0 Interrupt cycle time (s):                       1.789006
CPU 0 ISR highest execution time (µs):                42.409941
CPU 0 ISR total execution time (s):                   0.074250
CPU 0 ISR count:                                      11248
CPU 0 DPC highest execution time (µs):                1348.676243
CPU 0 DPC total execution time (s):                   0.418216
CPU 0 DPC count:                                      89551
_________________________________________________________________________________________________________
CPU 1 Interrupt cycle time (s):                       1.221662
CPU 1 ISR highest execution time (µs):                17.385317
CPU 1 ISR total execution time (s):                   0.000774
CPU 1 ISR count:                                      579
CPU 1 DPC highest execution time (µs):                505.764250
CPU 1 DPC total execution time (s):                   0.270982
CPU 1 DPC count:                                      25799
_________________________________________________________________________________________________________

I am  surprised that Norton was the hard page fault culprit. I disabled it for this run.
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RE: Cannot get low latency with USB audio gear - by Steven Minzer - 06-28-2020, 07:16 PM

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