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[Xen-devel] Load increase after memory upgrade (part2)
Hello again, I would like to come back to that thing...sorry that I did not have the time up to now. We (now) speak about - Xen 4.1.2
- Dom0 is Jeremy's 2.6.32.46 64 bit
- DomU in question is now 3.1.2 64 bit
- Same thing if DomU is also 2.6.32.46
- DomU owns two PCI cards (DVB-C) that o DMA
- Machine has 8GB, Dom0 pinned at 512MB
As compared to 2.6.34 Kernel with backported patches, the load on the DomU is at least twice as high. It will be "close to normal" if I reduce the memory used to 4GB. As you can see from the attachment, you once had an idea. So should we try to find something...? Carsten.
-----Ursprüngliche Nachricht-----
An: konrad.wilk <konrad.wilk@xxxxxxxxxx>;
CC: linux <linux@xxxxxxxxxxxxxx>; xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>;
Von: Carsten Schiers <carsten@xxxxxxxxxx>
Gesendet: Mi 29.06.2011 23:17
Betreff: AW: Re: Re: Re: AW: Re: [Xen-devel] AW: Load increase after memory upgrade?
> Lets first do the c) experiment as that will likely explain your load average increase.
...
> >c). If you want to see if the fault here lies in the bounce buffer
> being used more
> >often in the DomU b/c you have 8GB of memory now and you end up using
> more pages
> >past 4GB (in DomU), I can cook up a patch to figure this out. But an
> easier way is
> >to just do (on the Xen hypervisor line): mem=4G and that will make
> think you only have
> >4GB of physical RAM. If the load comes back to the normal "amount"
> then the likely
> >culprit is that and we can think on how to fix this.
You are on the right track. Load was going down to "normal" 10% when reducing
Xen to 4GB by the parameter. Load seems to be still a little, little bit lower
with Xenified Kernel (8-9%), but this is drastically lower than the 20% we had
before.
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