When "GlassWire Control Service" is running during a fast download the DPC latency skyrockets and makes the PC nearly unusable to the point of the entire system including mouse cursor is freezing (incognito mode on downloading application doesn't help))

@Thinking

If you go to the top left GlassWire menu and choose “About” what version does it say you have, and what version of Windows do you have?

What does it mean “during a fast download”? Is it Bittorrent?

We designed GlassWire to use Windows APIs to monitor network activity that should cause no latency.

Version is as of writing this the current one (2.1.158). Windows version is Windows 10 Enterprise 1903, although I should mention that I had this issue on a previous install of Windows 10 Enterprise LTSC (1809 equivalent) as well.

By “fast download” I mean anything roughly above 100mbit. This is based on the fact that when I still had a 100mbit connection I didn’t have this issue as bad but it has really gotten noticeable when I upgraded (happened immediately when I plugged into the new connection so it’s not a coincidence).

As I mentioned, from my experience it’s the worst with Steam downloads which download directly from Steam servers (so no torrenting going on).

Edit: I am also surprised that it can even cause any interruptions of this kind, I also forgot to mention, there is no suspiciously high CPU usage of any processes while this happens so the monitoring must be straight up interrupting the Windows network components on a low level.

Thanks, we will investigate and see if we can recreate it. We have several million people who have downloaded GlassWire so if there was a common latency issue it seems like it would show up by now.

If you open the Windows task manager and choose “performance” does the software you are using show the same results?

@Thinking

I think you must realize this but it appears the software you posted called “Latencymon” checks for “if a system running Windows is suitable for processing real-time audio”.

Am I mistaken that this app does not check for network latency at all? I misunderstood and I thought you were reporting an issue with GlassWire and network latency.

The website for that software then has more info:

“Windows is not a real-time operating system. All requests to the operating system are delivered on a best effort basis. There are no guarantees whatsoever that requests are delivered within a certain time frame, which are the characteristics of a real-time operating system. That is not a problem for most devices and tasks but this is bad news for audio applications (which are considered soft real-time) because they need to deliver data to the subsystem and the hardware in buffers several times per second. If one or more buffers miss their deadlines and are not delivered in time it has audible consequences which are recognized as dropouts, clicks and pops.”

So, am I understanding correctly that you are reporting GlassWire is causing real-time audio problems with your PC? I see now I missed that part, sorry about that.

Can you tell me what audio app you are using that is having latency issues so we can test with it, or is this just results from the Latencymon app and everything is OK?

Sorry for the misunderstanding.

Our team discussed the issue further @thinking. Are you sure your audio drivers are up to date? Please check, and if they are not try running the software again and see if it helps.

Thanks for your report.

Can you tell me what audio app you are using that is having latency issues so we can test with it, or is this just results from the Latencymon app and everything is OK?

Our team discussed the issue further @thinking. Are you sure your audio drivers are up to date?

I have done extensive experimenting in regard to the issues you just brought up because I had this issue for a while but only now connected it to GlassWire, I also have some previous experience in regards to DPC latency from when I worked on a Gaming PC virtualization project a couple years ago:

  1. It’s not affecting a specific audio app. The most common symptom for DPC latency in small amounts is audio crackling or distortion, this is why Latencymon is so targeted towards audio professionals. However in the very big amount found here it not only affects audio but also freezes the entire system for up to a couple milliseconds. This can potentially cause some big issues (although luckily I haven’t had anything beyond some unexplained system crashing every few months) because it throws off the timing by significant amounts for the entire system, for example the system clock shows significant (in the context of a PC clock that is synced very often) deviation and another sympton is audio/video becoming unsynchronized in software that doesn’t automatically correct it (this used to be an issue on YouTube for me).

  2. The audio and network drivers were what I was looking at for a very long time previously, I have done everything from letting them be stock as they come with Windows, installed the newest from the respective websites and for my audio driver I also installed the generic realtek driver which excludes issues related to outdated drivers from my motherboard manufacturer. With nothing solving my issue. Keep in mind that this issue persisted at least across two independent (e.g. completely fresh with full reformat) installs of Windows.

Really the major for me here is the extremely clear connection from the GlassWire service running to the high latency occurring, the fact that no unexpected CPU usage happens while this is happening just further confirms for me that something in the way GlassWire is monitoring the firewall must affect the real time performance of some low level Windows component.

Update:

I just ran a speed test 6 times, 3 times with the service running and 3 times with it stopped. I ran all of the tests on the same speedtest server from speedtest.net .

Service Running:LatMon_2019-09-06_13-33-37

LatMon_2019-09-06_13-34-24

LatMon_2019-09-06_13-35-08

Service Stopped:

LatMon_2019-09-06_13-36-06

LatMon_2019-09-06_13-36-45

LatMon_2019-09-06_13-37-51

Notes:

  1. The last of the “service stopped” results is much higher than the other ones from that series, it was also the test where the speedtest jumped up the fastest, still doesn’t come close to the “service running” results.

  2. I didn’t manage/bother to get a screenshot of the actual speedtest speed because I would have to wait for the upload test to complete and since this didn’t matter here (I only have 50mbit up which isn’t enough to show any significant latency) I just reset once download was done.

However, I know approximately what the speed was, with the service running it was around 600/750 mbit down, with it stopped it easily reached 800 and usually ended up at 900mbit.

Thanks for this detailed info! Our team will investigate.

For me personally, I use some different audio apps and I have never noticed any popping or issues and I always use GlassWire 100% of the time. But all hardware/software is different. We will work to try to recreate this issue on our side.

It appears this latency app shows all kinds of issues but do you actually experience any audio issues on your PC while using GlassWire?

Meanwhile we’re working on a major GlassWire update that has some options that will allow you to reduce resource usage considerably so please be on the lookout for the update.

One thing our team immediately suggested was to update your drivers. It appears you already looked into that but if anyone else experiences the issue please give that a try.

Did Speedtest itself show any changes in speed at all while running GlassWire? I just ran a Speedtest test myself (and I have done so in the past) and I could see no difference. My PC hardware is nothing special and not very high end.

I can see the Latency app showed issues but I am curious if you saw issues with the network activity on Speedtest at all? If you run any other background app like an antivirus, or browser does it have the same latency issues? GlassWire does use computer resources like most other software, but I wonder if any app that uses many resources can cause audio latency issues?

do you actually experience any audio issues on your PC while using GlassWire?

When there is strong network activity, yes, alongside the other mentioned issues.

Did Speedtest itself show any changes in speed at all while running GlassWire?

I mentioned this in my previous comment, there was a decrease in download speed while GW was running.

If you run any other background app like an antivirus, or browser does it have the same latency issues?

I only use Windows Defender in the background and the browser is just as affected as any other app on the system, I mentioned YouTube as an example.

GlassWire does use computer resources like most other software, but I wonder if any app that uses many resources can cause audio latency issues?

Not to that extent, I can run games at settings that make my FPS single digits and things like audio playback will still be fine, this kind of timing issues usually doesn’t happen even with applications using a lot of resources, the CPU scheduling is there to prevent this.

Edit: I also found this thread: Very high DPC routine execution time for TCPIP.SYS with Glasswire 1.20 At least one other person experienced this issue.

Edit 2: I assume “network auto scanning” is the “Things” monitor? I have that already disabled.

Edit 3: What is the download speed you are using for testing? My setup didn’t show symptoms that significantly (although there was still some audio crackling and audio/video desync here and there) before I upgraded to Gigabit.

1 Like

@Ken_GlassWire
The approach taken in thus topic needs to be more disciplined to correctly diagnose the issue on @thinking’s system.

High DPC times are a performance issue where a CPU is unable to process interrupts in a timely manner.
Therefore you can’t be sure of diagnosing or duplicating the cause without, at minimum, the relevant CPU configuration details and performance stats. Personally, I’d also want to know the details for the system board / chipset and NIC.
This all becomes more important the more that the system and components are loaded. For example, is the NIC using interrupt moderation or, more importantly, not.

@Thinking, you’d help by providing the GlassWire team with the monitoring reports from LatencyMon or whatever else you are using.

While GlassWire may be implicated, it is not a good idea to ignore an identified issue. ndis.sys has high DPC time, so that should be diagnosed, e.g. realtek drivers are notorious for problems. Ndis.sys is the network driver so why would you not look at it when you are stress testing network throughput. See this example of high DPC times for ndis.sys.

1 Like

For anyone who is interested in these issues of interrupt processing delays (ISR, DPC latency), there is an easy to read article from the NT Insider, a journal about Windows system programming: Windows and Real-Time

1 Like

I run LatencyMon occasionally to test my system for real-time audio. DPCs and ISRs can affect any program running on the system not just audio, but real-time audio is the most sensitive. Most other applications can buffer data and slow down, but otherwise weather typical delays fine.

So far I have seen no indication on my system of the effects described by the OP in response to the GW Control Service. With his system freezing up, there is apparently a serious conflict going on somewhere in the PC ecosystem.

LatencyMon provides a nice summary report of the DPC and ISR usage for all drivers observed during the monitoring period. Anything with excessively high usage needs to be investigated.

Here is a summary from the software developer that explains a few details (just replace audio program with a generic placeholder, and don’t get hung up on audio):

https://www.resplendence.com/latencymon

About DPCs and ISRs

The Windows thread disptacher (also known as scheduler) which is part of the kernel executes threads based on a priority scheme. Threads with higher priority will be given a longer execution time (also known as quantum or time slice) than threads with a lower priority. However the kernel also knows other types of units of execution known as interrupt service routines (ISRs). Devices connected to the system may interrupt on a connected CPU and cause their interrupt service routines to execute. An interrupt can occur on the same processor that an audio program is running on. Any thread that was running on the processor on which an interrupt occured will be temporarily halted regardless of its priority. The interrupt service routine (ISR) is executed and may schedule a DPC (Deferred Procedure Call) to offload an amount of work. The DPC will most likely run immediately on the same processor which means the audio application will halt until both the ISR and the DPC routines have finished execution. That is because ISRs and DPCs run at elevated IRQL which means they cannot become preempted by the thread dispatcher (scheduler). Therefore to guarantee responsiveness of the system, ISR and DPC routines should execute as fast as possible. Guidelines say that they should not spend more than 100 µs of execution time however this is often not reached due to hardware factors beyond the control of the driver developer. If execution time gets too high, the audio program may be unable to deliver audio buffers to the hardware in a timely manner.

2 Likes

To show the reporting that is available, I ran Resplendence Software’s LatencyMon version 6.71 to monitor a speed test on my 5 year old gaming laptop. I found no concern over GlassWire but I will also disable GlassWire and run the speed test for comparison in the next post.

Incidentally, I’ve used several Resplendence tools and they’ve all been very good to excellent.

My network speed test

I ran my ISP’s version of OOKLA SpeedTest Custom over my home Gigabit LAN. The maximum theoretical throughput on this cable (HFC) plan is 900/100 Mbps and normally we’d max out at 700/100. This test was during the middle of a business day so download speed was only 500 Mbps. My ISP rate limits the upload speed to 100 Mbps which is why it barely ever changes on speed tests.

LatencyMon report tabs

Main

Stats

LatencyMon indicates that real-time audio would probably drop out during the network speed test.
Note the warning that the CPU wasn’t running full throttle. Any improvement in CPU throughput should lower the DPC latency.

The NDIS driver is servicing the network speed test so it is no surprise to see it have the highest ISR and DPC times.

Firefox is running the speed test so it is no surprise to see it generates them most hard page faults:

CPU 0 is the only CPU of concern because it is running the network driver. See the CPUs tab below for more detail.

Processes

Hard Page Faults are data that was expected in memory but was not so had to be retrieved from the HDD or SSD. As expected they occurred for Firefox running the speed test and LatencyMon doing the monitoring.

Drivers

The drivers stats are sorted by the highest reported DPC execution time. Note that this report displays in milliseconds instead of the microseconds used in the Main tab.

The GlassWire driver stats show that DPC latency is not being directly produced by this driver:

CPUs

CPU 0 is the CPU being loaded by the network speed test. It has more than 5 times the CPU time of all the other CPUs.

GlassWire

The GlassWire UI was not running during the speed test. The screenshot mainly shows the speed test throughput.

1 Like

Remah,

You made me jealous, would be great to have these speeds…

1 Like

I repeated the speed test without the driver running. As expected when Windows is not gathering data for GlassWire, there is much better performance as the original post reported.

The question is whether it is possible to get better performance from network monitoring? So there’s further scenarios I want to compare for my satisfaction. I don’t plan to provide all the screenshots unless there is something significant that I find:

  • GlassWire incognito mode.
  • GlassWire running but the various threat protection drivers disabled (Windows Defender Firewall Windows Defender Antivirus, Windows Defender Threat Protection)
  • GlassWire disabled but running another network monitor.

Speed Test with GlassWire disabled

The speed test throughput is much higher. 682 Mbps versus 532 Mbps with GlassWire.

LOL, I don’t even need that speed but my sons like it for their gaming. :racing_car:

LatencyMon with GlassWire disabled

Main

No DPC latency issues without GlassWire running.

Stats




Processes

Drivers

CPUs

1 Like

I tried two other network monitoring options without GlassWire and repeated the GlassWire running and not running scenarios as higher throughput is being achieved:

  1. GlassWire disabled and Windows Resource Monitor running
    :arrow_right: 738/101
  2. GlassWire disabled and Windows Message Analyzer running
    :arrow_right: 797/101
  3. GlassWire disabled
    :arrow_right: 735/100
  4. GlassWire enabled
    :arrow_right: 607/100

The only scenario that clearly slows throughput is when GlassWire is running.

Apologies for the long post. :blush:

Scenario 1 - Speed test with GlassWire disabled and Windows Resource Monitor running

Speed test

Higher throughput, maybe because lots of parents have got off their computers and gone to get their kids from school!?

Windows Resource Monitor running

LatencyMon

Text report

CONCLUSION


Your system appears to be suitable for handling real-time audio and other tasks without dropouts.
LatencyMon has been analyzing your system for 0:00:50 (h:mm:ss) on all processors.


SYSTEM INFORMATION


Computer name: ME08
OS version: Windows 10 , 10.0, version 1903, build: 18362 (x64)
Hardware: Alienware 17, Alienware, 0MPYM4
CPU: GenuineIntel Intel® Core™ i7-4710MQ CPU @ 2.50GHz
Logical processors: 8
Processor groups: 1
RAM: 16265 MB total


CPU SPEED


Reported CPU speed: 2494 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): 298.0
Average measured interrupt to process latency (µs): 18.499961

Highest measured interrupt to DPC latency (µs): 273.60
Average measured interrupt to DPC latency (µs): 9.510706


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): 94.274258
Driver with highest ISR routine execution time: ndis.sys - Network Driver Interface Specification (NDIS), Microsoft Corporation

Highest reported total ISR routine time (%): 0.451270
Driver with highest ISR total time: ndis.sys - Network Driver Interface Specification (NDIS), Microsoft Corporation

Total time spent in ISRs (%) 0.484532

ISR count (execution time <250 µs): 529091
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): 473.726945
Driver with highest DPC routine execution time: ndis.sys - Network Driver Interface Specification (NDIS), Microsoft Corporation

Highest reported total DPC routine time (%): 2.498758
Driver with highest DPC total execution time: ndis.sys - Network Driver Interface Specification (NDIS), Microsoft Corporation

Total time spent in DPCs (%) 2.567489

DPC count (execution time <250 µs): 473790
DPC count (execution time 250-500 µs): 0
DPC count (execution time 500-999 µs): 22
DPC count (execution time 1000-1999 µs): 0
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: firefox.exe

Total number of hard pagefaults 8
Hard pagefault count of hardest hit process: 8
Number of processes hit: 1


PER CPU DATA


CPU 0 Interrupt cycle time (s): 13.256916
CPU 0 ISR highest execution time (µs): 87.053729
CPU 0 ISR total execution time (s): 1.935567
CPU 0 ISR count: 528699
CPU 0 DPC highest execution time (µs): 473.726945
CPU 0 DPC total execution time (s): 10.162841
CPU 0 DPC count: 459548


CPU 1 Interrupt cycle time (s): 0.464824
CPU 1 ISR highest execution time (µs): 14.535686
CPU 1 ISR total execution time (s): 0.000033
CPU 1 ISR count: 6
CPU 1 DPC highest execution time (µs): 215.061748
CPU 1 DPC total execution time (s): 0.036412
CPU 1 DPC count: 3134


CPU 2 Interrupt cycle time (s): 0.296266
CPU 2 ISR highest execution time (µs): 94.274258
CPU 2 ISR total execution time (s): 0.003011
CPU 2 ISR count: 199
CPU 2 DPC highest execution time (µs): 167.391740
CPU 2 DPC total execution time (s): 0.036337
CPU 2 DPC count: 5096


CPU 3 Interrupt cycle time (s): 0.333218
CPU 3 ISR highest execution time (µs): 51.784282
CPU 3 ISR total execution time (s): 0.001322
CPU 3 ISR count: 180
CPU 3 DPC highest execution time (µs): 110.810746
CPU 3 DPC total execution time (s): 0.006164
CPU 3 DPC count: 973


CPU 4 Interrupt cycle time (s): 0.244039
CPU 4 ISR highest execution time (µs): 3.528468
CPU 4 ISR total execution time (s): 0.000004
CPU 4 ISR count: 1
CPU 4 DPC highest execution time (µs): 90.807137
CPU 4 DPC total execution time (s): 0.01470
CPU 4 DPC count: 2046


CPU 5 Interrupt cycle time (s): 0.180139
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): 68.181636
CPU 5 DPC total execution time (s): 0.004782
CPU 5 DPC count: 604


CPU 6 Interrupt cycle time (s): 0.222445
CPU 6 ISR highest execution time (µs): 4.977145
CPU 6 ISR total execution time (s): 0.000012
CPU 6 ISR count: 6
CPU 6 DPC highest execution time (µs): 92.115878
CPU 6 DPC total execution time (s): 0.012226
CPU 6 DPC count: 1589


CPU 7 Interrupt cycle time (s): 0.183152
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): 68.854050
CPU 7 DPC total execution time (s): 0.006148
CPU 7 DPC count: 822


Drivers

Scenario 2 - Speed test with GlassWire disabled and Windows Message Analyzer running

Installed 64-bit version 1.4 build 4.0.8112.0
No optimization for data capture.
Run as administrator.
Select File | Favorite scenarios | Local network interfaces

Windows Message Analyzer

Speed test

LatencyMon

Main

Text report

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 0:00:53 (h:mm:ss) on all processors.


SYSTEM INFORMATION


Computer name: ME08
OS version: Windows 10 , 10.0, version 1903, build: 18362 (x64)
Hardware: Alienware 17, Alienware, 0MPYM4
CPU: GenuineIntel Intel® Core™ i7-4710MQ CPU @ 2.50GHz
Logical processors: 8
Processor groups: 1
RAM: 16265 MB total


CPU SPEED


Reported CPU speed: 2494 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): 1504.90
Average measured interrupt to process latency (µs): 19.472324

Highest measured interrupt to DPC latency (µs): 1494.90
Average measured interrupt to DPC latency (µs): 13.693991


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): 113.959904
Driver with highest ISR routine execution time: ndis.sys - Network Driver Interface Specification (NDIS), Microsoft Corporation

Highest reported total ISR routine time (%): 0.306606
Driver with highest ISR total time: ndis.sys - Network Driver Interface Specification (NDIS), Microsoft Corporation

Total time spent in ISRs (%) 0.331768

ISR count (execution time <250 µs): 400533
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): 1583.478749
Driver with highest DPC routine execution time: ndis.sys - Network Driver Interface Specification (NDIS), Microsoft Corporation

Highest reported total DPC routine time (%): 2.705536
Driver with highest DPC total execution time: ndis.sys - Network Driver Interface Specification (NDIS), Microsoft Corporation

Total time spent in DPCs (%) 2.807986

DPC count (execution time <250 µs): 391774
DPC count (execution time 250-500 µs): 0
DPC count (execution time 500-999 µs): 275
DPC count (execution time 1000-1999 µs): 8
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: messageanalyzer.exe

Total number of hard pagefaults 440
Hard pagefault count of hardest hit process: 409
Number of processes hit: 5


PER CPU DATA


CPU 0 Interrupt cycle time (s): 14.782769
CPU 0 ISR highest execution time (µs): 113.959904
CPU 0 ISR total execution time (s): 1.399446
CPU 0 ISR count: 399788
CPU 0 DPC highest execution time (µs): 1583.478749
CPU 0 DPC total execution time (s): 11.606116
CPU 0 DPC count: 350258


CPU 1 Interrupt cycle time (s): 0.544429
CPU 1 ISR highest execution time (µs): 77.085004
CPU 1 ISR total execution time (s): 0.002034
CPU 1 ISR count: 149
CPU 1 DPC highest execution time (µs): 105.149960
CPU 1 DPC total execution time (s): 0.104512
CPU 1 DPC count: 12789


CPU 2 Interrupt cycle time (s): 0.473912
CPU 2 ISR highest execution time (µs): 88.546913
CPU 2 ISR total execution time (s): 0.002221
CPU 2 ISR count: 174
CPU 2 DPC highest execution time (µs): 134.056937
CPU 2 DPC total execution time (s): 0.109732
CPU 2 DPC count: 16226


CPU 3 Interrupt cycle time (s): 0.257482
CPU 3 ISR highest execution time (µs): 54.097835
CPU 3 ISR total execution time (s): 0.003411
CPU 3 ISR count: 306
CPU 3 DPC highest execution time (µs): 138.938252
CPU 3 DPC total execution time (s): 0.012819
CPU 3 DPC count: 2072

Processes

Drivers

Scenario 0 - Speed test with GlassWire running

Speed test

Compared with GlassWire not running

LatencyMon

Main

Stats

Summary

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 0:01:23 (h:mm:ss) on all processors.


SYSTEM INFORMATION


Computer name: ME08
OS version: Windows 10 , 10.0, version 1903, build: 18362 (x64)
Hardware: Alienware 17, Alienware, 0MPYM4
CPU: GenuineIntel Intel® Core™ i7-4710MQ CPU @ 2.50GHz
Logical processors: 8
Processor groups: 1
RAM: 16265 MB total


CPU SPEED


Reported CPU speed: 2494 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): 2098.40
Average measured interrupt to process latency (µs): 17.063021

Highest measured interrupt to DPC latency (µs): 2093.50
Average measured interrupt to DPC latency (µs): 8.979410


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): 125.466319
Driver with highest ISR routine execution time: ndis.sys - Network Driver Interface Specification (NDIS), Microsoft Corporation

Highest reported total ISR routine time (%): 0.147704
Driver with highest ISR total time: ndis.sys - Network Driver Interface Specification (NDIS), Microsoft Corporation

Total time spent in ISRs (%) 0.168421

ISR count (execution time <250 µs): 332388
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): 1153.143545
Driver with highest DPC routine execution time: ndis.sys - Network Driver Interface Specification (NDIS), Microsoft Corporation

Highest reported total DPC routine time (%): 0.033806
Driver with highest DPC total execution time: ndis.sys - Network Driver Interface Specification (NDIS), Microsoft Corporation

Total time spent in DPCs (%) 0.116231

DPC count (execution time <250 µs): 295912
DPC count (execution time 250-500 µs): 0
DPC count (execution time 500-999 µs): 27
DPC count (execution time 1000-1999 µs): 1
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: firefox.exe

Total number of hard pagefaults 11
Hard pagefault count of hardest hit process: 6
Number of processes hit: 6


PER CPU DATA


CPU 0 Interrupt cycle time (s): 3.252233
CPU 0 ISR highest execution time (µs): 125.466319
CPU 0 ISR total execution time (s): 1.108349
CPU 0 ISR count: 330361
CPU 0 DPC highest execution time (µs): 1153.143545
CPU 0 DPC total execution time (s): 0.609303
CPU 0 DPC count: 276858


CPU 1 Interrupt cycle time (s): 0.546852
CPU 1 ISR highest execution time (µs): 63.308741
CPU 1 ISR total execution time (s): 0.010848
CPU 1 ISR count: 1863
CPU 1 DPC highest execution time (µs): 245.713713
CPU 1 DPC total execution time (s): 0.053786
CPU 1 DPC count: 5832


CPU 2 Interrupt cycle time (s): 0.604561
CPU 2 ISR highest execution time (µs): 15.289094
CPU 2 ISR total execution time (s): 0.000249
CPU 2 ISR count: 66
CPU 2 DPC highest execution time (µs): 866.514836
CPU 2 DPC total execution time (s): 0.039609
CPU 2 DPC count: 4187


CPU 3 Interrupt cycle time (s): 0.384163
CPU 3 ISR highest execution time (µs): 5.357658
CPU 3 ISR total execution time (s): 0.000057
CPU 3 ISR count: 21
CPU 3 DPC highest execution time (µs): 78.032077
CPU 3 DPC total execution time (s): 0.007104
CPU 3 DPC count: 1042

Processes

Drivers

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Thanks for doing this detailed testing @Remah! We will test on our machines/network also.

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I ran some more tests with Microsoft Message Analyzer to see if there was any difference if I used a broader range of scenarios than only Local Network Interfaces.

The result was the essentially the same as in the above posts for the four scenarios I tried. The Speed Test was faster if the GlassWire service wasn’t running (682-803 Mbps) than when it was (528-571 Mbps).

I used the Wired Local Area Network favorite scenario which can be revealed by editing the favorites. It had the worst impact on my system but as a sample size of one this may be misleading. But it got me thinking that maybe filtering by connection is an issue for GlassWire?

I also created three new scenarios:

  • Microsoft-Windows-WFP as shown in the screenshot below
  • Microsoft-Windows-Base-Filtering-Engine-Connections
  • Microsoft-Windows-Kernel-Network

Steps to create scenario

New Session button
Add Data Source button
Live Trace button
Add Providers button
Add System Providers in drop-down list
Select provider from Available System Providers list
Add to Selected Providers
OK button
Start button

Incidentally, Microsoft Message Analyzer (MMA) is very useful for kernel trace logging if you don’t need to use Event Tracing for Windows (ETW) and Event Trace Logs (ETL) e.g. to log Windows startup. MMA will view/pars ETL files but also appears to do a better job of decoding event info than Windows Event Viewer. I haven’t used WEV with Windows 10 but MMA certainly seemed easier to read.

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It’s been two weeks, is there any update on this (or just an official acknowledgement of the issue)? This is a pretty important issue for people with fast internet.

Thanks for your super in depth analysis Remah!

Thanks for your detailed report @Remah. Our network is not as fast as yours, that’s cool!

I will say that we have many Fortune 500 companies using our software on their servers on fast networks and I don’t ever recall a report from an ISP or company who said we slow something related to the network.

We’ll see if we can recreate this on our end.

Meanwhile we’re in the final month or so of our backend rewrite that we have been working on for awhile. The update will use less resources and will allow us to move forward with our MacOS version hopefully before the year is out.