Re: [libvirt] [V2]RFC for support cache tune in libvirt
Hi Martin,
Thanks for your comments, it’s really helpful, I’v changed some of the design and with
some PoC code.
And will later sent the v3 version of cachetune for libvirt, will add you in CC list.
I have some PoC code based on 3.0.0, not finished yet. But I’v learned that 3.0.0 will be
released soon, seems there will be some rebase work to do.
Best Regards
Eli Qiao(乔立勇）OpenStack Core team OTC Intel.
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On 09/01/2017, 9:09 PM, "Martin Kletzander" <mkletzan(a)redhat.com> wrote:
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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