Hi,
On 02/17/2017 11:02 AM, Dario Faggioli wrote:
Just very quickly...
On Thu, 2017-02-16 at 15:07 -0800, Stefano Stabellini wrote:
(XEN) Active queues: 1
(XEN) default-weight = 256
(XEN) Runqueue 0:
(XEN) ncpus = 4
(XEN) cpus = 0-3
(XEN) max_weight = 256
(XEN) instload = 1
(XEN) aveload = 3208 (~1%)
(XEN) l(XEN) idlers: 00000000,00000000,00000000,0000000a
a(XEN) tickled: 00000000,00000000,00000000,00000000
t(XEN) fully idle cores: 00000000,00000000,00000000,0000000a
e(XEN) Domain info:
n(XEN) Domain: 0 w 256 v 4
c(XEN) 1: [0.0] flags=2 cpu=0 credit=10500000 [w=256] load=3170 (~1%)
(XEN) 2: y[0.1] flags=0 cpu=1 credit=10500000 [w=256]( load=131072 (~50%)
(XEN) 3: n[0.2] flags=0 cpu=2s credit=10500000 [w=256]) load=131072 (~50%):
(XEN) 4: [0.3] flags=0 cpu=3m credit=10500000 [w=256]a load=131072 (~50%)x
Status of vcpus 2, 3 and 4 is a bit weird. I'll think about it.
=(XEN) Domain: 1 w 256 v 1
1(XEN) 5: 1[1.0] flags=2 cpu=2 credit=9713074 [w=256] load=56 (~0%)
(XEN) Runqueue info:
6(XEN) runqueue 0:
9(XEN) CPUs info:
0(XEN) CPU[00] runq=0, sibling=00000000,00000000,00000000,00000001,
wcore=00000000,00000000,00000000,00000001
This tells me that nr_cpu_ids is very big (I think it tells it is 128,
i.e., ARM default), which means cpumask_t-s are huge.
What does `xl info' says. On my (x86) test box, it's like this:
...
nr_cpus : 16
max_cpu_id : 63
...
(and I have NR_CPUS=256, i.e., x86 the default).
Cpumasks being bigger also means cpumask operation being slower, and
this matters quite a bit in Credit2, because we use cpumasks a lot (but
also in Credit1, because we use cpumasks a little less than in Credit2,
but still quite a bit).
Isn't there a way, on ARM, to figure out online that you're not going
to have 128 cpus in the platform?
It is just we never set nr_cpu_ids on ARM :/. There was a patch on the
ML a while ago [1] but never got applied.
Stefano, I think the patch is still valid. Could you apply it?
It would probably be worth to do the benchmark again with this patch
applied.
Cheers,
[1] https://patchwork.kernel.org/patch/8177261/
--
Julien Grall
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel