[vbox-dev] ICH9 devices

Ananth Pallapothu apallapothu at gmail.com
Tue Jan 5 23:04:51 UTC 2016

Right, AHCI isn't behind bridge, I misread.

I certainly need network and disk.

Devices I see in my ICH9, VGA-CustomPassThrough, VGA, E1000, VMMDev, ACPI,
LPC, ich9pcibridge 1, ich9pcibridge 2, AHCI, USB-OHCI

Can I disable LPC, 2 bridges ? I can't seem to find the commands in user
manual though.

I am thinking slowness can be because CPU has to execute more instructions
coming from "other extra" devices in ICH9 but when I am fairly using same
setup, drivers as I used on PIIX3 ... not sure why ICH9 would take longer
which infact we expect it to be faster. Please comment.


On Fri, Jan 1, 2016 at 1:04 PM, Michal Necasek <michal.necasek at oracle.com>

>  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.
> Thanks.
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