Messages in this thread | | | Subject | Re: [Xen-devel] linux 4.4 Regression: 100% cpu usage on idle pv guest under Xen with single vcpu. | From | Boris Ostrovsky <> | Date | Tue, 1 Dec 2015 17:47:58 -0500 |
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On 11/30/2015 05:55 PM, Sander Eikelenboom wrote: > On 2015-11-30 23:54, Boris Ostrovsky wrote: >> On 11/30/2015 04:46 PM, Sander Eikelenboom wrote: >>> On 2015-11-30 22:45, Konrad Rzeszutek Wilk wrote: >>>> On Sat, Nov 28, 2015 at 04:47:43PM +0100, Sander Eikelenboom wrote: >>>>> Hi all, >>>>> >>>>> I have just tested a 4.4-rc2 kernel (current linus tree) + the tip >>>>> tree >>>>> pulled on top. >>>>> >>>>> Running this kernel under Xen on PV-guests with multiple vcpus >>>>> goes well (on >>>>> idle < 10% cpu usage), >>>>> but a guest with only a single vcpu doesn't idle at all, it seems >>>>> a kworker >>>>> thread is stuck: >>>>> root 569 98.0 0.0 0 0 ? R 16:02 12:47 >>>>> [kworker/0:1] >>>>> >>>>> Running a 4.3 kernel works fine with a single vpcu, bisecting >>>>> would probably >>>>> quite painful since there were some breakages this merge window >>>>> with respect >>>>> to Xen pv-guests. >>>>> >>>>> There are some differences in the diff's from booting a 4.3, >>>>> 4.4-single, >>>>> 4.4-multi cpu boot: >>>> >>>> Boris has been tracking a bunch of them. I am attaching the latest >>>> set of >>>> patches I've to carry on top of v4.4-rc3. >>> >>> Hi Konrad, >>> >>> i will test those, see if it fixes all my issues and report back >> >> They shouldn't help you ;-( (and I just saw a message from you >> confirming this) >> >> The first one fixes a 32-bit bug (on bare metal too). The second fixes >> a fatal bug for 32-bit PV guests. The other two are code >> improvements/cleanup. > > One of these patches also fixes a bug i was having with a > pci-passthrough device in > a HVM that wasn't working (depending on which dom0-kernel i was using > (4.3 or 4.4)), > but didn't report yet. > > Fingers crossed but i think this pv-guest single vcpu issue is the > last i'm troubled by for now ;)
I could not reproduce this, including with your kernel config file.
-boris
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