[vbox-dev] ICH9 devices

Michal Necasek michal.necasek at oracle.com
Fri Jan 1 18:04:54 UTC 2016

Not sure what you're referring to. Your driver specifically? Or the entire guest OS? In general, there is not known to be any significant performance difference between the chipsets either way. Specific devices might perform faster with ICH9 (e.g. xHCI with MSIs is faster than xHCI without) but the difference isn't huge. 

If it's your driver specifically then... well, why is it behaving so differently? Only you can find out. 

Most of the devices aren't "required" as far as VirtualBox is concerned, but there's only so far you can get without disk or network. 

FYI, in my VM, AHCI definitely isn't behind a bridge. It's at bus/dev/fn 0:1f:02. 

- Michal 

----- Original Message ----- 
From: apallapothu at gmail.com 
To: vbox-dev at virtualbox.org 
Sent: Thursday, December 31, 2015 2:52:49 AM GMT +01:00 Amsterdam / Berlin / Bern / Rome / Stockholm / Vienna 
Subject: [vbox-dev] ICH9 devices 

Hello Experts, 

My "custom" driver execution takes long with ICH9 as compared to PIIX3, ~4X difference. Custom device is a pluggable device registered. 
Apart from 2 "ich9pcibridge" devices I don't see any thing else "new" in ICH9. 
With ICH9, AHCI is connected on other side of the bridge (on bus 2), while on PIIX3, it is on the root port. Could this be the reason for slowness ? 
I used same settings between the two chipsets, have disabled "audio" in both instances since I don't need them. Is there a way to reduce overall traffic ? 
I presume all current devices in ICH9 are required (?) but is there a way to improve performance ? I am not much bothered about other devices, apart from having functional chipset. 

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