Operating System Windows 7 - DPC Latency Spikes (1 Viewer)

[doveman]

I was having trouble with audio/video glitches and seemed to have tracked down the cause of the high DPC spikes to Outpost Security Suite Free, which was definitely causing them and killing it stopped them.

They've started recurring again though, not as bad or often as before and I haven't observed any glitches but I still need to sort out what's causing them.

I've tried disabling the Realtek PCIe GBE NIC, the AMD High Definition Audio Device (on my 6950), the Realtek motherboard audio, the two Reneas Electronics USB 3.0 Host Controller devices and the VIA 1394 OHCI Compliant Host Controller but still I'm getting occasional spikes of 1000-2000us. Actually, I've just re-enabled the Realtek NIC and didn't see anything above 435us for a few minutes, but just got a spike of 1523us.

I don't really know what the stats mean in LatencyMon, so I've uploaded a screenshot if someone who does could be good enough to take a look for me.

 

[mm1352000]

Hi

ISR = interrupt service routine
DPC = deferred procedure call

You can read about what they mean on Wikipedia or elsewhere but basically the lower the values in all three columns, the better. I'd be paying attention to the top 3 devices in the list:

network
IDE/ATA HDD controllers (I think)
USB

Your USB controller seems to have a particularly high average execution time for the ISR which causes many DPCs (at least that is the way I read it). Probably the worst culprit.
The network controller has a higher average execution time but less DPCs - perhaps this driver causes occasional big delays randomly.

mm

 

[doveman]

Hi

ISR = interrupt service routine
DPC = deferred procedure call

You can read about what they mean on Wikipedia or elsewhere but basically the lower the values in all three columns, the better. I'd be paying attention to the top 3 devices in the list:

network
IDE/ATA HDD controllers (I think)
USB

Your USB controller seems to have a particularly high average execution time for the ISR which causes many DPCs (at least that is the way I read it). Probably the worst culprit.
The network controller has a higher average execution time but less DPCs - perhaps this driver causes occasional big delays randomly.

mm

Thanks.

I've only got one SATA HDD connected (but in IDE mode) and no CD/DVD, so I guess it must be the HDD, unless it's my RAMdisk. I'd normally have Daemon Tools installed but haven't got round to installing that yet.

I'll try disabling the various USB devices (hopefully without disabling my mouse!) to see if I can find a culprit.

It sounds like the NIC could be responsible for the occasional (1 every 2-3 minutes maybe) high spikes I'm getting. Certainly things are loads better since I disabled Outpost Security Suite, I think tcpip.sys was about 0.7 when that was running and it was producing a spike about once every 5 seconds!

 

[mm1352000]

I've only got one SATA HDD connected (but in IDE mode) and no CD/DVD, so I guess it must be the HDD, unless it's my RAMdisk.

Just to note: my understanding is that it is more about the controller drivers than the HDDs themselves. In other words, secondary IDE/ATA controllers that don't have drives connected could conceivably (okay maybe a little unlikely but still...) cause issues.

 

[doveman]

I've only got one SATA HDD connected (but in IDE mode) and no CD/DVD, so I guess it must be the HDD, unless it's my RAMdisk.

Just to note: my understanding is that it is more about the controller drivers than the HDDs themselves. In other words, secondary IDE/ATA controllers that don't have drives connected could conceivably (okay maybe a little unlikely but still...) cause issues.

Thanks for the clarification. I've got three Standard Dual Channel PCI IDE Controller and three each of ATA Channel 0 and ATA Channel 1 (which correlates with the six SATA ports). My SATA HDD is on the first ATA Channel 0. This board doesn't have any real IDE support. I'll see if I can disable (in the BIOS) the SATA ports I'm not using.

I might as well try disabling the RAMdisk as well, just in case.

 

[jameson_uk]

I'll try disabling the various USB devices (hopefully without disabling my mouse!) to see if I can find a culprit.

Remember that your nova t 500 is actually a USB device.

 

[doveman]

Thanks, good point. That shows up as VIA Controller so it's easy enough to avoid disabling though.

Well I disabled the two Standard Dual Channel PCI IDE Controllers (one of which is off a PCI standard PCI-to-PCI bridge) that don't have anything connected, the 1394 Controller, the AMD 6950 HD Audio, the two USB 3 Controllers, three Standard Enhanced PCI to USB Host Controllers and three Standard OpenHCD USB Host Controllers.

I think it's helped lower the average latency, so it's mostly around 100us with some spikes up to 200us, but I'm still getting the occasional spike up to 550us or 1000us. I don't think the drivers stats have really changed much either. I'm not sure how long I'd been monitoring before taking the previous screenshot, but this one was after 0:05:30.



I didn't bother disabling the RAMdisk as I checked and it's using partmgr.sys and RAMDiskVE.sys, not ataport.sys like my real HDD. The only other things I can think of trying are unplugging the USB mouse and keyboard (connected via a KVM) and disabling the Hauppauge tuner, although I do wonder if any of the myriad of options under Advanced for the NIC might have some affect.

EDIT: Whilst looking at the NIC I noticed that the Agnitum Firewall Driver (part of Outpost Security Suite) was still enabled for it, although the firewall is shutdown. After unticking that, the tcpip.sys Highest Execution Time has dropped from 0.259ms to 0.199ms and the Highest latency in 0:05:30 was 478us, so hopefully that's fixed it and I don't need to do any more.



Heck, seems I spoke too soon. After 15mins USBPORT.SYS hit 1.3ms and the Highest Latency has spiked to 926us.

 

[doveman]

OK, I think I'm getting somewhere.

I unplugged all my USB devices and after 37mins the highest latency was around 500us. As soon as I plugged my KVM back in, it jumped to 1060us. I actually have it plugged in the USB 3 ports, which I assume are running as USB 2 because I've disabled both Renesas Electronics USB 3 Host Controllers (which are each under a PCI Standard PCI-to-PCI bridge). There's also a small utility (nusb3mon.exe) that is part of the motherboard drivers that's running, so I'll try killing that and if that doesn't help, plug the KVM into one of the USB 2 ports.

I'm a bit confused, as besides the two USB 3 Host controllers, there's three Standard Enhanced PCI to USB Host Controllers and four Standard OpenHCD USB Host Controllers. Each controller supports two ports, so one USB 3 controller would be for the two external ports and the other for the internal port, then two of the PCI to USB and OpenHCD USB controllers would be for the four external USB 2 ports, then there's two internal USB 2 ports which accounts for the third PCI to USB and OpenHCD USB controller, which leaves one OpenHCD USB controller with no associated PCI to USB controller. I can only assume this is for the two eSATA / USB 2.0 Combo ports which don't use a PCI to USB controller. Although there must be a controller assigned to the two USB 3 ports so that they still work (in USB 2 mode) when the two USB 3 Host controllers are disabled, so perhaps that uses the fourth OpenHCD USB controller and the Combo ports run off something completely different (I can't imagine what though).

EDIT at 18:04: Well killing nusb3mon.exe seems to have brought the max execution time down for USBPORT.sys from 1.3ms to 0.38ms, but still that's rather high.

So I plugged the KVM into a USB2/SATA combo port, which kept it down to about 0.25ms, but within 15 minutes I got a spike highest ISR execution time (not shown on the drivers tab) on ataport.sys, although that may have been a coincidence.






So then I plugged the KVM into a normal USB2 port and after 32mins (43mins now) it hasn't had any problems, although the USBPORT.sys and ataport.sys max times haven't really changed from the 0.2-0.25 they were when in my first post. ndis.sys is now at the top as it's increased from 0.03ms to 0.2ms and lately 0.28ms, which seems to have happened since I disabled the Agnitum/OSS driver (I've now uninstalled OSS, although I don't think I've rebooted since, so I ought to do that).

 

[doveman]

This is a flippin nightmare. It was OK for a while after I uninstalled Outpost and installed Comodo, but now I've installed VMware it's worse than ever.

If I disable the two NICs VMware installs, it's OK again, so it's definitely that.

 

[tourettes]

This is a flippin nightmare. It was OK for a while after I uninstalled Outpost and installed Comodo, but now I've installed VMware it's worse than ever.

If I disable the two NICs VMware installs, it's OK again, so it's definitely that.

Just an advice - do not try to use HTPC for anything else than media playback. VMWare has no function in HTPC if you are after quality playback.