100% CPU due to hardware interrupts?

lynchknot · August 8th, 2006

I too have high cpu but looking at my task manager told me nothing so I downloaded process explorer - However, I don't understand hardware interrupts and how to solve this problem. My mouse and keyboard become very sluggish until it stops - and that is often a very long time. This guy didn't seem to get anywhere but "reformat" - http://www.daniweb.com/techtalkforums/thread7297.html

**kcnychief** · August 8th, 2006

Actually your task manager tells you all you need to know, perhaps you didn't know how to interpret it?

UTORRENT.EXE, TASKMGR.EXE, SVCHOST.EXE, SERVICES.EXE AND CHSERVICE.EXE are all using 20% of your CPU.

UTORRENT especially can be a resource hog - are you using a Beta or a stable build. I would also recommend playing with your bandwidth settings, as that can change how agressive the app itself is.

lynchknot · August 8th, 2006

If I shut down utorrent, taskmanager, chservice - other apps will take their place and I still will have 100% cpu. Systernals indicates it's actually hardware interrupts that is at a high level. Perhaps it has something to do with, "I just switched it back to DMA mode this morning and it has already reverted back to PIO mode this afternoon. I have Win XP sp2, and that thread suggests that it's most likely a hardware problem if its occuring post sp2"

Here after several hours the interrupts stop. This screenshot is with all the same apps open

**kcnychief** · August 8th, 2006

Well that makes sense, that other applications take the place of ones you close.

If an application wants to run, and it can't because there are no CPU cycles available, they will sit in queue of sorts and run when they can.

The only real test would be to kill all running programs, at that point System Idle should be at 99%

lynchknot · August 9th, 2006

Basically, you are telling me you don't know what hardware interrupts are and why systernals shows a 95% cpu draw via hardware interrupts and task manager shows it as a application draw?

jimi_81 · August 9th, 2006

a guess says.. its the motherboard talking to the peripheral?
wikipedia says:

In computing, an interrupt is an asynchronous signal from hardware or software indicating the need for attention. A hardware interrupt causes the processor to save its state of execution via a context switch, and begins execution of an interrupt handler. Software interrupts are usually implemented as instructions in the instruction set, which cause a context switch to the interrupt handler similarly to a hardware interrupt. Interrupts are a commonly used technique for computer multitasking, especially in real-time computing. Such a system is said to be interrupt-driven.

lynchknot · August 9th, 2006

I don't know. It's weird. For a while it's 100% then suddenly we are back down to 0% with all the same apps open - including Utorrent still actively up/downloading.

**kcnychief** · August 9th, 2006

I do know what they are, I just have to take one on the chin and admit I only skimmed the previous post.

I guess I would ask next as to what hardware changes, if any, you have made recently?

lynchknot · August 9th, 2006

no changes.

lynchknot · August 9th, 2006

Here's another instance that this happens. The second I start to unpack a winrar file, the hardware interrupts skyrocktet from a low % to high % but task manager will show sudden increase in CPU for some apps that were only using 0-2% cpu a second ago. Not just what you see in this screenshot but many apps that always stay at 2% or less are not jumping to 20%+- just because I opened winrar? ***edit - winrar is done, now all apps are back down to 0-2%. Interrupts back down to 2%

jimi_81 · August 9th, 2006

i remember once a guy having an issue where his ethernet card was getting on in age, and his system was running like crap because of it. we took it out and it worked just fine.

the system's performance was restored.

lynchknot · August 9th, 2006

It's running fine now. It seems to be limited to unpacking winrar and opening utorrent (had same issue with azerues) but once utorrent is open and CPU's finally drop down to normal, utorrent is no longer an issue while it's open. Starting these two apps is the issue as it seems these are the only two that provoke hardware interrupts.

lynchknot · August 23rd, 2006

I had some issue with connection so I just decided to True Image. When I did I lost my other partition information and it would not show that partition in "my computer". I decided to run Test Disk then Spinrite (because I did not think I used test disk correctly) long story short, I have no high "Hardware Interrupts" at all now. It was 95% while unpacking a rar file but now it's less than 5% unpacking.

**LeeJend** · August 23rd, 2006

If it's only happening on HD intensive tasks it sounds like the HD controller (or the HD itself) is having problems. If you don't have Smarts turned on in bios turn it on so the HD can do and report full diagnostics. Run the HD manufacturer's diagnostic program (after smarts is turned on).

It could also be an IRQ assignment conflict. If you have an expansion cards installed swap slots. This will change the IRQ used.

It's been a long time (decades) since I looked at the wintel device level architecture but from what I recall Windows maps almost all the hardware devices down into just a couple hardware interupts (as opposed to a polling system) using software interrupt requests IRQs. The keyboard might have had a hardware interrupt and the watchdog timer.

The problem is all the devices eventually map into a "hardware interrupt" so anything could be misfiring and producing excessive requests for servicing. If you want to isolate it start pulling/disabling hardware one device at a time (sound, USB, CD/DVD, LAN, etc). It could be a MB problem too. An unterminated input on the interrupt controller could just be bouncing around causing false inteerupts. Something like a heavy disk access (rar, downloads, etc) could be causing higher noise levels and more false interrupts.

Isolate what you can and if nothing removes the problem then the MB is suspect.

**X-Istence** · August 23rd, 2006

On my old laptop, with a PCMCIA Ethernet card, interrupts will max out the available CPU time especially when transferring at high speeds.

It has to do with the fact that some hardware is firing an interrupt to get attention for something it has waiting/wants done. Do what LeeJend said, and see if you can find the problem hardware. Keep in mind that it could be something totally unrelated, like a keyboard or a mouse.

lynchknot · August 23rd, 2006

Originally Posted by LeeJend

If it's only happening on HD intensive tasks it sounds like the HD controller (or the HD itself) is having problems. If you don't have Smarts turned on in bios turn it on so the HD can do and report full diagnostics. Run the HD manufacturer's diagnostic program (after smarts is turned on).

It could also be an IRQ assignment conflict. If you have an expansion cards installed swap slots. This will change the IRQ used.

It's been a long time (decades) since I looked at the wintel device level architecture but from what I recall Windows maps almost all the hardware devices down into just a couple hardware interupts (as opposed to a polling system) using software interrupt requests IRQs. The keyboard might have had a hardware interrupt and the watchdog timer.

The problem is all the devices eventually map into a "hardware interrupt" so anything could be misfiring and producing excessive requests for servicing. If you want to isolate it start pulling/disabling hardware one device at a time (sound, USB, CD/DVD, LAN, etc). It could be a MB problem too. An unterminated input on the interrupt controller could just be bouncing around causing false inteerupts. Something like a heavy disk access (rar, downloads, etc) could be causing higher noise levels and more false interrupts.

Isolate what you can and if nothing removes the problem then the MB is suspect.

I'm not sure if you read my post correctly or maybe I wasn't clear but I do appreciate your response. Here is the condition under unpacking winrar now (no interrupt problem) when I did have the interrupts it would require over an hour to unpack a 700mb winrar file but now does it in 50 seconds!!!!!!: Also, I might add that I did recover that lost partition on the main drive with all data intact.

But specs are really bad for a relatively new HD. From what I've been reading Seagate will spec badly to begin with so I don't know what to think. This HD had been in use since only June.

**LordOfLA** · August 23rd, 2006

High interrupt levels using utorrent would indicate you've got more traffic to and from your pc than your nic can handle and it is then hammering the cpu. You'll need to reduce settings in utorrent related to transfers or buy a better nic (intel pro 1000mt for instance)

From the hdd indicates a storage subsystem fault.

lynchknot · August 25th, 2006

Originally Posted by LordOfLA

High interrupt levels using utorrent would indicate you've got more traffic to and from your pc than your nic can handle and it is then hammering the cpu. You'll need to reduce settings in utorrent related to transfers or buy a better nic (intel pro 1000mt for instance)

From the hdd indicates a storage subsystem fault.

I don't have a separate network card. I run it off my MB: Abit NF7-S v2.0. The network adaptor is an NVIDIA nForce MCP Networking Controller.

I have done nothing but run Test Disk and Spinrite - the interrupts are gone. However, I don't know what this is telling me. Perhaps it's not even related but just a coincidence.

I'm not sure what you are referring to regarding, "hdd indicates a storage subsystem fault" do you meant the SMART results?

lynchknot · August 28th, 2006

Perhaps I should add:

****edit - one more thing: I do quite a bit of large file transfers and deleting in my main drive second partion. I was seeing this error weeks prior to the interrupts. Upon (somehow) fixing the interrupt solved this issue as well. Unfortunately, this error has returned. As usual, the second attempt finds the folder

lynchknot · September 4th, 2006

Well, no one at sysinternals would even respond to my post (100 views) - so they, apparently, don't even know. I appreciate those who have responded here and tried to come up with a cause. I'm guessing that the fact it has to do with unpacking a rar or downloading, it's something to do with I/O but then how could running Test Disk fix the problem?

*edit - this thread received 624 views. There must be a relatively high degree of interest as it's a topic that is rarely covered.

August 8th, 2006	Top \| #1
lynchknot OSNN Senior Addict Joined: September 2002 Posts: 800 Reputation: 160 Power: 128	100% CPU due to hardware interrupts? I too have high cpu but looking at my task manager told me nothing so I downloaded process explorer - However, I don't understand hardware interrupts and how to solve this problem. My mouse and keyboard become very sluggish until it stops - and that is often a very long time. This guy didn't seem to get anywhere but "reformat" - http://www.daniweb.com/techtalkforums/thread7297.html Firefox Themes THE TRUTH<>THE RIDE

August 8th, 2006	Top \| #2
kcnychief █▄█ ▀█▄ █ Joined: April 2005 Location: Massachusetts Posts: 16,949 Reputation: 4941 Power: 305	Re: 100% CPU due to hardware interrupts? Actually your task manager tells you all you need to know, perhaps you didn't know how to interpret it? UTORRENT.EXE, TASKMGR.EXE, SVCHOST.EXE, SERVICES.EXE AND CHSERVICE.EXE are all using 20% of your CPU. UTORRENT especially can be a resource hog - are you using a Beta or a stable build. I would also recommend playing with your bandwidth settings, as that can change how agressive the app itself is. XBOX Live Gamertag: kcnychief

August 8th, 2006	Top \| #3
lynchknot OSNN Senior Addict Joined: September 2002 Posts: 800 Reputation: 160 Power: 128	Re: 100% CPU due to hardware interrupts? If I shut down utorrent, taskmanager, chservice - other apps will take their place and I still will have 100% cpu. Systernals indicates it's actually hardware interrupts that is at a high level. Perhaps it has something to do with, "I just switched it back to DMA mode this morning and it has already reverted back to PIO mode this afternoon. I have Win XP sp2, and that thread suggests that it's most likely a hardware problem if its occuring post sp2" Here after several hours the interrupts stop. This screenshot is with all the same apps open Firefox Themes THE TRUTH<>THE RIDE

August 8th, 2006	Top \| #4
kcnychief █▄█ ▀█▄ █ Joined: April 2005 Location: Massachusetts Posts: 16,949 Reputation: 4941 Power: 305	Re: 100% CPU due to hardware interrupts? Well that makes sense, that other applications take the place of ones you close. If an application wants to run, and it can't because there are no CPU cycles available, they will sit in queue of sorts and run when they can. The only real test would be to kill all running programs, at that point System Idle should be at 99% XBOX Live Gamertag: kcnychief

August 9th, 2006	Top \| #5
lynchknot OSNN Senior Addict Joined: September 2002 Posts: 800 Reputation: 160 Power: 128	Re: 100% CPU due to hardware interrupts? Basically, you are telling me you don't know what hardware interrupts are and why systernals shows a 95% cpu draw via hardware interrupts and task manager shows it as a application draw? Firefox Themes THE TRUTH<>THE RIDE

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August 9th, 2006	Top \| #6
jimi_81 OSNN Senior Addict Joined: May 2002 Location: Stoney Creek, ON, Canada Posts: 820 Reputation: 500 Power: 135	Re: 100% CPU due to hardware interrupts? a guess says.. its the motherboard talking to the peripheral? wikipedia says: In computing, an interrupt is an asynchronous signal from hardware or software indicating the need for attention. A hardware interrupt causes the processor to save its state of execution via a context switch, and begins execution of an interrupt handler. Software interrupts are usually implemented as instructions in the instruction set, which cause a context switch to the interrupt handler similarly to a hardware interrupt. Interrupts are a commonly used technique for computer multitasking, especially in real-time computing. Such a system is said to be interrupt-driven.

August 9th, 2006	Top \| #7
lynchknot OSNN Senior Addict Joined: September 2002 Posts: 800 Reputation: 160 Power: 128	Re: 100% CPU due to hardware interrupts? I don't know. It's weird. For a while it's 100% then suddenly we are back down to 0% with all the same apps open - including Utorrent still actively up/downloading. Firefox Themes THE TRUTH<>THE RIDE

August 9th, 2006	Top \| #8
kcnychief █▄█ ▀█▄ █ Joined: April 2005 Location: Massachusetts Posts: 16,949 Reputation: 4941 Power: 305	Re: 100% CPU due to hardware interrupts? I do know what they are, I just have to take one on the chin and admit I only skimmed the previous post. I guess I would ask next as to what hardware changes, if any, you have made recently? XBOX Live Gamertag: kcnychief

August 9th, 2006	Top \| #9
lynchknot OSNN Senior Addict Joined: September 2002 Posts: 800 Reputation: 160 Power: 128	Re: 100% CPU due to hardware interrupts? no changes. Firefox Themes THE TRUTH<>THE RIDE

August 9th, 2006	Top \| #10
lynchknot OSNN Senior Addict Joined: September 2002 Posts: 800 Reputation: 160 Power: 128	Re: 100% CPU due to hardware interrupts? Here's another instance that this happens. The second I start to unpack a winrar file, the hardware interrupts skyrocktet from a low % to high % but task manager will show sudden increase in CPU for some apps that were only using 0-2% cpu a second ago. Not just what you see in this screenshot but many apps that always stay at 2% or less are not jumping to 20%+- just because I opened winrar? ***edit - winrar is done, now all apps are back down to 0-2%. Interrupts back down to 2% Firefox Themes THE TRUTH<>THE RIDE

August 9th, 2006	Top \| #11
jimi_81 OSNN Senior Addict Joined: May 2002 Location: Stoney Creek, ON, Canada Posts: 820 Reputation: 500 Power: 135	Re: 100% CPU due to hardware interrupts? i remember once a guy having an issue where his ethernet card was getting on in age, and his system was running like crap because of it. we took it out and it worked just fine. the system's performance was restored.

August 9th, 2006	Top \| #12
lynchknot OSNN Senior Addict Joined: September 2002 Posts: 800 Reputation: 160 Power: 128	Re: 100% CPU due to hardware interrupts? It's running fine now. It seems to be limited to unpacking winrar and opening utorrent (had same issue with azerues) but once utorrent is open and CPU's finally drop down to normal, utorrent is no longer an issue while it's open. Starting these two apps is the issue as it seems these are the only two that provoke hardware interrupts. Firefox Themes THE TRUTH<>THE RIDE

August 23rd, 2006	Top \| #13
lynchknot OSNN Senior Addict Joined: September 2002 Posts: 800 Reputation: 160 Power: 128	Re: 100% CPU due to hardware interrupts? I had some issue with connection so I just decided to True Image. When I did I lost my other partition information and it would not show that partition in "my computer". I decided to run Test Disk then Spinrite (because I did not think I used test disk correctly) long story short, I have no high "Hardware Interrupts" at all now. It was 95% while unpacking a rar file but now it's less than 5% unpacking. Firefox Themes THE TRUTH<>THE RIDE

August 23rd, 2006	Top \| #14
LeeJend OSNN Veteran Addict Joined: January 2003 Location: Fort Worth, TX Posts: 5,261 Reputation: 3386 Power: 199	Re: 100% CPU due to hardware interrupts? If it's only happening on HD intensive tasks it sounds like the HD controller (or the HD itself) is having problems. If you don't have Smarts turned on in bios turn it on so the HD can do and report full diagnostics. Run the HD manufacturer's diagnostic program (after smarts is turned on). It could also be an IRQ assignment conflict. If you have an expansion cards installed swap slots. This will change the IRQ used. It's been a long time (decades) since I looked at the wintel device level architecture but from what I recall Windows maps almost all the hardware devices down into just a couple hardware interupts (as opposed to a polling system) using software interrupt requests IRQs. The keyboard might have had a hardware interrupt and the watchdog timer. The problem is all the devices eventually map into a "hardware interrupt" so anything could be misfiring and producing excessive requests for servicing. If you want to isolate it start pulling/disabling hardware one device at a time (sound, USB, CD/DVD, LAN, etc). It could be a MB problem too. An unterminated input on the interrupt controller could just be bouncing around causing false inteerupts. Something like a heavy disk access (rar, downloads, etc) could be causing higher noise levels and more false interrupts. Isolate what you can and if nothing removes the problem then the MB is suspect. Thought for the new millenium: In a world without walls and fences, who needs Windows and Gates? - Open Office - Firefox - Thunderbird - Gimp -Ubuntu - Red Hat -

August 23rd, 2006	Top \| #15
X-Istence * Joined: December 2001 Location: USA Posts: 6,496 Reputation: 2808 Power: 220	Re: 100% CPU due to hardware interrupts? On my old laptop, with a PCMCIA Ethernet card, interrupts will max out the available CPU time especially when transferring at high speeds. It has to do with the fact that some hardware is firing an interrupt to get attention for something it has waiting/wants done. Do what LeeJend said, and see if you can find the problem hardware. Keep in mind that it could be something totally unrelated, like a keyboard or a mouse. An engineers technical notebook

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August 23rd, 2006	Top \| #16
lynchknot OSNN Senior Addict Joined: September 2002 Posts: 800 Reputation: 160 Power: 128	Re: 100% CPU due to hardware interrupts? Originally Posted by LeeJend If it's only happening on HD intensive tasks it sounds like the HD controller (or the HD itself) is having problems. If you don't have Smarts turned on in bios turn it on so the HD can do and report full diagnostics. Run the HD manufacturer's diagnostic program (after smarts is turned on). It could also be an IRQ assignment conflict. If you have an expansion cards installed swap slots. This will change the IRQ used. It's been a long time (decades) since I looked at the wintel device level architecture but from what I recall Windows maps almost all the hardware devices down into just a couple hardware interupts (as opposed to a polling system) using software interrupt requests IRQs. The keyboard might have had a hardware interrupt and the watchdog timer. The problem is all the devices eventually map into a "hardware interrupt" so anything could be misfiring and producing excessive requests for servicing. If you want to isolate it start pulling/disabling hardware one device at a time (sound, USB, CD/DVD, LAN, etc). It could be a MB problem too. An unterminated input on the interrupt controller could just be bouncing around causing false inteerupts. Something like a heavy disk access (rar, downloads, etc) could be causing higher noise levels and more false interrupts. Isolate what you can and if nothing removes the problem then the MB is suspect. I'm not sure if you read my post correctly or maybe I wasn't clear but I do appreciate your response. Here is the condition under unpacking winrar now (no interrupt problem) when I did have the interrupts it would require over an hour to unpack a 700mb winrar file but now does it in 50 seconds!!!!!!: Also, I might add that I did recover that lost partition on the main drive with all data intact. But specs are really bad for a relatively new HD. From what I've been reading Seagate will spec badly to begin with so I don't know what to think. This HD had been in use since only June. Firefox Themes THE TRUTH<>THE RIDE

August 23rd, 2006	Top \| #17
LordOfLA Godlike! Joined: February 2004 Location: Salisbury, Wiltshire, UK Posts: 7,031 Blog Entries: 5 Reputation: 4137 Power: 213	Re: 100% CPU due to hardware interrupts? High interrupt levels using utorrent would indicate you've got more traffic to and from your pc than your nic can handle and it is then hammering the cpu. You'll need to reduce settings in utorrent related to transfers or buy a better nic (intel pro 1000mt for instance) From the hdd indicates a storage subsystem fault. If HK-47 and GLaDOS had a child, the character they create would cause the video game world to overdose on awesome. -sheridanmovieguy: Dragon age forum user.

August 25th, 2006	Top \| #18
lynchknot OSNN Senior Addict Joined: September 2002 Posts: 800 Reputation: 160 Power: 128	Re: 100% CPU due to hardware interrupts? Originally Posted by LordOfLA High interrupt levels using utorrent would indicate you've got more traffic to and from your pc than your nic can handle and it is then hammering the cpu. You'll need to reduce settings in utorrent related to transfers or buy a better nic (intel pro 1000mt for instance) From the hdd indicates a storage subsystem fault. I don't have a separate network card. I run it off my MB: Abit NF7-S v2.0. The network adaptor is an NVIDIA nForce MCP Networking Controller. I have done nothing but run Test Disk and Spinrite - the interrupts are gone. However, I don't know what this is telling me. Perhaps it's not even related but just a coincidence. I'm not sure what you are referring to regarding, "hdd indicates a storage subsystem fault" do you meant the SMART results? Firefox Themes THE TRUTH<>THE RIDE

August 28th, 2006	Top \| #19
lynchknot OSNN Senior Addict Joined: September 2002 Posts: 800 Reputation: 160 Power: 128	Re: 100% CPU due to hardware interrupts? Perhaps I should add: ****edit - one more thing: I do quite a bit of large file transfers and deleting in my main drive second partion. I was seeing this error weeks prior to the interrupts. Upon (somehow) fixing the interrupt solved this issue as well. Unfortunately, this error has returned. As usual, the second attempt finds the folder Firefox Themes THE TRUTH<>THE RIDE

September 4th, 2006	Top \| #20
lynchknot OSNN Senior Addict Joined: September 2002 Posts: 800 Reputation: 160 Power: 128	Re: 100% CPU due to hardware interrupts? Well, no one at sysinternals would even respond to my post (100 views) - so they, apparently, don't even know. I appreciate those who have responded here and tried to come up with a cause. I'm guessing that the fact it has to do with unpacking a rar or downloading, it's something to do with I/O but then how could running Test Disk fix the problem? *edit - this thread received 624 views. There must be a relatively high degree of interest as it's a topic that is rarely covered. Firefox Themes THE TRUTH<>THE RIDE