It is not the same VM but an identical VM with the same settings. Base Memory, CPU's, Nesting .... exactly same settings as used on PIIX3.
Reason I am inclined to think in terms of devices is because, while experimenting with MSI when I enabled logging with DEV_PCI, PDM, PDM_DEVICE, DEV_APIC following which I saw bunch of calls as below (apart from my passthrough device) pdmR3DevHlp_PhysRead: caller='ahci'/0 ..... pdmR3DevHlp_PhysRead: caller='e1000'/0 ...... pdmR3DevHlp_PhysRead: caller='VMMDev'/0 ..... At this point I am not really expecting anything to happen over network, so thought devices could be causing the issues. On Wed, Jan 6, 2016 at 4:22 PM, Michal Necasek <michal.neca...@oracle.com> wrote: > > There's no architected way to disable the bridges or the LPC device > because no user needs to do it. You could probably do it by modifying the > source code. > > You should be able to disable network and USB. Beyond that you will have > trouble booting anything. > > I can only repeat again that I know of no reason why the ICH9 chipset > should be significantly slower or faster than the default chipset. If you > think there is extra code being executed, you should be able to find it > with a debugger or a profiler. I can't help you because I never heard of > such behavior. > > Did you compare the exact same VM where only the chipset was different? > Or are you comparing VMs that aren't really otherwise identical? > > Regards, > Michal > > ----- Original Message ----- > From: apallapo...@gmail.com > To: michal.neca...@oracle.com > Cc: vbox-dev@virtualbox.org > Sent: Wednesday, January 6, 2016 12:04:54 AM GMT +01:00 Amsterdam / Berlin > / Bern / Rome / Stockholm / Vienna > Subject: Re: [vbox-dev] ICH9 devices > > 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. > > Thanks. > > > > > On Fri, Jan 1, 2016 at 1:04 PM, Michal Necasek <michal.neca...@oracle.com> > wrote: > >> >> 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: apallapo...@gmail.com >> To: vbox-dev@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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