Re: [Xen-devel] [for-4.8 PATCH] xen: credit2: make runqueues be per-socket by default.

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 29.11.16 at 12:42, <wei.liu2@xxxxxxxxxx> wrote:
> On Tue, Nov 29, 2016 at 12:33:24PM +0100, Dario Faggioli wrote:
>> On Tue, 2016-11-29 at 11:14 +0000, Wei Liu wrote:
>> > On Tue, Nov 29, 2016 at 11:57:03AM +0100, Dario Faggioli wrote:
>> > Strictly speaking, this is not necessary for 4.8 because even though
>> > the
>> > default configuration is not optimal, there is a simple way to change
>> > it.
>> > 
>> Absolutely true.
>> 
>> > On the other hand, because credit2 is declared supported in this
>> > release, it is better to have a sensible default setting for credit2.
>> > 
>> Exactly.
>> 
>> > The risk is that changing the default value would cause osstest to
>> > discover bugs in the scheduler logic, hence blocking the release. But
>> > overall I think the chance is low, but Dario can you please state to
>> > what extend did you test this patch?
>> > 
>> I've tried to state that in the cover letter:
>> https://lists.xen.org/archives/html/xen-devel/2016-11/msg02616.html 
>> 
> 
> Ah, I thought that was a dupe because it had the same subject line as
> the patch, so I skipped it.

Same here, albeit I had noticed I shouldn't have got 2 copies, so
I did look into the other one.

>> In some more details, it is _months_ that I and Anshul run benchmarks
>> with Credit2 running in this configuration.
>> 
>> It's months that, all the time that I boot my test box, either to do
>> Credit2 related development and testing, or completely unrelated things
>> (e.g., recently, when testing the new Fedora 25 as HVM and PV guest), I
>> use Credit2 in this configuration.
>> 
>> George has done some runs of his schedbench suite with this
>> configuration (to compare Credit1 vs Credit2 per-core vs Credit2 per-
>> socket).
>> 
>> So, if you ask me "how much is this tested", my answer would be "really
>> really really a lot". :-)
>> 
> 
> OK. This is rather convincing to me. I will wait a bit for other people
> express their opinion.

FWIW, I'm in favor of putting it in with the background provided.

Jan


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