Re: [libvirt] [V2]RFC for support cache tune in libvirt
On Fri, Dec 23, 2016 at 05:38:13AM +0000, Qiao, Liyong wrote:
Hi folks
I’v send the V1 version RFC early this week, but no reply yet.
I replied to that and since I was going through the mail
chronologically, and this is not a reply to that one, I am getting to
this one only now.
Thanks Qiaowei for the comment, I’v change the RFC much more libvirt
specify, please help to comments on.
##Propose Changes
#Libvirtd configure changes
Add a new configure option cache_allocation_ratio to libvirtd, which let libvirt to
allocate how many cache to domains.
Where would be this option? In libvirtd.conf? Why?
Default is 0.5
Eg.
On a host which has 55M cache, libvirt can allocate 55M * cache_allocation_ratio cache to
domains
Why does this have to be statically limited?
## Virsh command line changes:
NAME
cachetune - control or query domain cache allocation
SYNOPSIS
cachetune <domain> [--enabled true/false] [--type <type>][--size
<number>] [--config] [--live] [--current]
DESCRIPTION
Allocate cache usage for domain.
OPTIONS
[--domain] <string> domain name, id or uuid
--enabled <true/false> enable cache allocation
So if I want to clear it out, I do "cachetune --enable false"? That's a
mouthful.
--type <string> cache allocations type, support l3/l2 etc
--size <number> the cache size in KB
--config affect next boot
--live affect running domain
--current affect current domain
This will allow libvirt to allocate specify type l3 cache for a domain
Domain xml changes:
<cachetune>
<enabled=’yes’, size=4096, actual_size=4680,type=’l3’>
<enabled=’no’, size=256, actual_size=0, type=’l2’>
</cachetune>
<cachetune> sounds fine, but the rest... enabled=no doesn't make sense,
same as actual_size=0, but I guess that's just the same thing. It's
also missing code/data differentiation. And socket/vCPU information.
For more information about the detail design, please refer
https://www.redhat.com/archives/libvir-list/2016-December/msg01011.html
CAT intro:
https://software.intel.com/en-us/articles/software-enabling-for-cache-all...
Best Regards
Eli Qiao(乔立勇）OpenStack Core team OTC Intel.
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