[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] Regression, host crash with 4.5rc1



>>> On 25.11.14 at 10:38, <sflist@xxxxxxxxx> wrote:
> On 11/25/2014 12:16 AM, Jan Beulich wrote:
>> Interesting, so other than for me (perhaps due to other patches
>> I have in my tree) the change resulted in C states now being used
>> again despite mwait-idle=0, which is good. Question now is - with
>> this being the case, did the hangs re-occur?
> 
> Unfortunately they did. (Happened unusually quick this time, though I 
> doubt the statistical significance.) Not sure what the desirable output 
> is, so I did a couple of 'a' and 'd' requests, capped off by a 'c':

Okay, so it's not really the mwait-idle driver causing the regression,
but it is C-state related. Hence we're now down to seeing whether all
or just the deeper C states are affected, i.e. I now need to ask you
to play with "max_cstate=". For that you'll have to remember that the
option's effect differs between the ACPI and the MWAIT idle drivers.
In the spirit of bisection I'd suggest using "max_cstate=2" first no
matter which of the two scenarios you pick. If that still hangs,
"max_cstate=1" obviously is the only other thing to try. Should that
not hang (and you left out "mwait-idle=0"), trying "max_cstate=3"
in that same scenario would be the other case to check.

No need for 'd' and 'a' output for the time being, but 'c' output would
be much appreciated for all cases where you observe hangs.

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel


 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.