Windows: Line-Based vs. Message Signaled-Based Interrupts. MSI tool.

Yeh, I have same on my desktop too. (win10 1607).
One thing I notice on each upgrade from win7> win10 1511>win10 1607, each time it loaded a broadcom driver to the SMbus controller.
Normally this gets taken care of by Intel drivers and names it "SMbus host controller 1E22" I keep putting it back to Intel (version 10.1.1.33) right now.
Just wondering if anyone knows about that.

 

My rig has no such device "SMbus host controller 1E22". It is only "SM Bus Controler" with driver version "10.0.14393.0" and without actual driver for it.

 

the BT device on your mobo is from broadcom. probably windows 10 just has a newer driver for that and it is just labeled as a SMBus controller.
can you check the vendor id of the SMBus controller in the properties?
then you can look it up if it is that bluetooth device.

 

I will check that, I "assumed" it was Intel as it part of MB, Also I use snappy driver updater it it did list the broadcom driver as optimal (compared to intel one.
My Asus PZZ77Pro did have wireless controller on it, one of those that fit in back by I/O.
Anyway, I don't use it and its disabled, no wireless/bluetooth devices.

Manufacture =Intel for me (under properties and detail>manufacture )

 

Yes, It is that when broadcom driver is installed, name changes when you install Intel driver.
Oh, and your right, there no real driver loaded here, so I guess its just name, inf file.
I should of checked that before even looking at it.

 

Sigh, problems keep coming back it seems.

Any idea as to what can cause this priodical hitch?



Edit : I think the suspect might have been CPU parking!

 

Ignore all the bars except ISR and DPC execution time ones.
As for CPU core parking you can check whether it is happening easily.

 

Hi,Ive tried and use the MSI-mode utililty and when I run it it shows 0 devices and I cannot choose anything. What to do?

What about Messege Number Limit? What do I have to set this to?

I am enabling MSI mode from registry manually.

 

I stopped to read that thread after "disable HPET". People always like to play with things they do not understand (mostly because the do not have the necessary learning background that cannot be replaced by a wikipedia article...) and what they receive at most as best result is just a placebo.
PS: every version of Windows has it's own timing preference for a good reason. And all this "tweak" are lost in the OS overhead noise.

 

You should launch utility as administrator.

As for message number limit I assume that most of devices are limited to one message limit by default. If you see in Device manager that some device has more then one IRQ (with negative number) then it utilizes more then one message (and the limit can be applied).

 

Sorry if this has been addressed but how do I know if i use MSI mode? I did the registry tweaks but not sure if MSI mode is enabled or not

 

Open up Device manager, then go to view>resources by type.
Then expand the IRQ one and look at the values (scroll all way down), the ones with -xxx are MSI ones.

 

Just tested it with my current system and although I can say it might be a little bit better it's not that much better. Some people gain about 30fps well at least the videos I checked on youtube but they can also lie about it anyway done all the tweaks I can with process lasso to make sure my power mode is on max performance, all cores unparked, time resolution is at it's best and now my sound blaster z and gpu is set to msi mode. one thing I can say is my games feel a bit smoother but not by a crazy amount but just slightly. will do a 3dmark firestrike soon to see if my resuslts have improved.

 

On a fresh install of windows 10, my 950pro nvme m.2 shows MSI - MODE by default with MessegeNumberLimit set to 78 in registry.

What is going on?

 

Just ignore that message limit, OK? If all works properly why should you worry about it?

 

Without proper messege number limit, we don't know if it's working correctly. That is the problem.

Anyone know some real info around here...

 

Only developers of OS kernel and device drivers know real info on this.
But you can check whether MSI mode is utilized. Go to Device manager and click "View => Resources by type" in menu. Then expand IRQ root node and scroll down to PCI devices. There you will see whether PCI device in MSI mode by finding IRQ with negative value. If device shows only one IRQ then it means it uses only one message. if device shows several IRQs then it means it uses several messages (and can be limitted through that additional registry setting).

For example at my work one of the servers has 33 IRQs for Broadcom network card and 107 IRQs for IBM SAS/SATA controller (but this is server edition of OS). In multi-core/multi-CPU rigs device with multiple IRQs - messages - can be serviced by several cores/CPUs simultaniously.

http://www.monitis.com/blog/performance-tuning-windows-2012-network-subsystempart-1/

https://wiki.chipp.ch/twiki/pub/CmsTier3/NodeTypeFileServerHPDL380G7/ols2009-pages-169-1842.pdf

I searched for MSI mode and note that most of links are about network cards.

Edit: Another link which states that with MSI mode device manufacturer with drivers developers can adopt several approaches:

https://www.kernel.org/doc/Documentation/PCI/MSI-HOWTO.txt

Edit: You can rename message limit registry value (and reboot) to see if that changes anything. But I would not touch it. If device is in MSI mode by default then it probably has all the right settings. Another thing is when you turn MSI mode for a device yourself. In that case message limit registry value is not there and device can use unlimited number of IRQs. Only they did not. So far I have seen only network cards (in my rigs) with multiple IRQs in MSI mode.

Edit: After all you don`t have to toy with this tweak. If your rig works properly then you probably should not bother. If you want to gain some performance boost then tests and playthroughs can give you estimation of gained/lost performance. If device is not working in MSI mode then you sure will know about it.

 

Dunno if someone has posted the same before but here are my findings.
Someone here wrote that the 990FX chipset has errata problem with msi/msi-x.(Thank you!)
So i disabled msi mode on all my devices. even for the onboard network card.
And everything seems smoother now.

 

I did tried this wonderful method to change interrupt to MSI
but i wasnt able to modify 3 things


PCI SATA AHCI CONTROLLER INTEL (pc won't bot with RST or default windows drivers)

PCI USE ENCHANCE CONTROLLER both doesnt put on (MSI)
PCI SMBUS CONTROLLER seems like it cannot be MSI

any help?

 

You can forget about USB (v2) and SMBUS controllers. As for Intel`s SATA controller - MS` generic driver works in MSI-mode by default only in Win10, and Intel` drivers work in MSI-mode by default. Which chipset and which version of RST driver?