[libvirt] [PATH V10 12/12] Resctrl: Add nodecachestats

[Eli Qiao]

--  
Best regards  
Eli

天涯无处不重逢
a leaf duckweed belongs to the sea, where not to meet in life  

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On Tuesday, 7 March 2017 at 5:33 AM, Marcelo Tosatti wrote:

> On Mon, Mar 06, 2017 at 05:50:43PM +0800, Eli Qiao wrote:
> > Add new virsh command line `nodecachestats` to expose the cache usage
> > on a node.
> >  
> > Signed-off-by: Eli Qiao <liyong.qiao at intel.com (mailto:liyong.qiao at intel.com)>
> > ---
> > src/libvirt_private.syms | 3 ++-
> > src/qemu/qemu_driver.c | 12 ++++++++++
> > src/util/virresctrl.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++
> > src/util/virresctrl.h | 8 +++++++
> > tools/virsh-host.c | 49 ++++++++++++++++++++++++++++++++++++++
> > 5 files changed, 133 insertions(+), 1 deletion(-)
> >  
>  
>  
> It perhaps would be good to also report the largest contiguous region
> available: So that if the space is fragmented, management software
> can detect the situation beforehand.
>  
> Like this perhaps:
>  
>  
> # LD_LIBRARY_PATH=/root/git/libvirt/src/.libs/
> # /root/git/virshnodegetcachestats  
> ret=0 nparams=10
> L3.0: free=11520, max_contiguous=X.
> L3.1: free=11520, max_contiguous=X.
>  
>  


Marclo, thanks for your testing and comments.

Actually, I only expose the contiguous cache which can be allocated to VMs for now.

so

free == max_contiguous.

Othere will be one case:

schemata 1 = 1000 0000
schemata 2 = 0010 0000
default schemata should be 0001 1111 (schemata should be contiguous, so it can’t be 01011111

and free_size = 5 * min_cache_unit

virsh nodecachestats will report free=5 * min_cache_unit

next if a new vm requires cache of 1 * min_cache_unit

schemata 1 = 1000 0000
schemata 2 = 0010 0000
new VM’s schemata = 0100 0000
default schemata should be 0001 1111


so free_size is still 5 * min_cache_unit.

and   
virsh nodecachestats will report free=5 * min_cache_unit



I am not sure if that will meaningful to user we expose (fragmented) cache which can not be allocated to VMs.

>  
> Or:
>  
> L3.0.free: 11520
> L3.0.max_contiguous=X.
> L3.1.free: 11520
> L3.1.max_contiguous=X.
>  
> Not sure what is the preferred way to do this in libvirt.
>  
> Otherwise, testing looks good now.  

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