[ovirt-devel] [VDSM] rhel6.5 vs rhel7 performance in sampling

[Francesco Romani]

Hi everyone,

since the beginning of this week, saved the test day of course,
I'm doing tests and benchmarking on the scalable_sampling
patchset from me and Nir.

http://gerrit.ovirt.org/#/q/status:open+project:vdsm+branch:master+topic:scalable_sampling,n,z
(plus http://gerrit.ovirt.org/#/c/30751/)

I'm collecting quite a lot of data and still digesting them, but
I think it is safe to present a couple of pictures that shows
hoe much better rhel7 behaves with respect to rhel6.5.

platform:
on minidell (core i7, 4 cores, 8 threads, 16 GB Ram)
engine is a recent 3.5 ~beta2; storage domain is ISCSI
VDSM master from Jul 24 (not much as changed meantime)
hypervisor runs stock RHEL6.5 or stock RHEL7.0

test scenario:
boot 100 VMs (each 1cpu, 64 MB ram, 1GB disk)
start sampling on hypervisor using stats from /proc each 1/2 second
wait 10 minutes
stop sampling, save sample points
stop VMS

what we want to see here is how much resources VDSM alone wastes
in sampling during the common operations.
Of course the less is better.

Nothing fancy here, just the differences from RHEL6.5 to RHEL7.
See the attached graphs:
* baseline_{cpu,mem}.png is RHEL 6.5
* baseline_{cpu,mem}_7.png is RHEL 7.0
RHEL7 is so *much* better, switching the hypervisor host is by far
the biggest (and easiest) gain we achieved so far.

coming soon:
- discussion about the impact of the scalable_sampling topic branch
- move to 200, 300 ... 500 VMs on a single host.

PS: a couple of updates about specific points (Michal, Nir)
- still no luck with yappi on RHEL7, managed to do the above bench
  with 10 VMs and collected a profile.
- 30751 is a win, same of the last changes of http://gerrit.ovirt.org/#/c/29980/
  (revs 12, 13)
- will tick 'V' on http://gerrit.ovirt.org/#/c/29607/ once the last checks
  are passed (ETA late today or tomorrow)

Bests,

-- 
Francesco Romani
RedHat Engineering Virtualization R & D
Phone: 8261328
IRC: fromani
-------------- next part --------------
A non-text attachment was scrubbed...
Name: baseline_mem_7.png
Type: image/png
Size: 142921 bytes
Desc: not available
URL: <http://lists.ovirt.org/pipermail/devel/attachments/20140731/9b4ca142/attachment-0004.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: baseline_mem.png
Type: image/png
Size: 188196 bytes
Desc: not available
URL: <http://lists.ovirt.org/pipermail/devel/attachments/20140731/9b4ca142/attachment-0005.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: baseline_cpu_7.png
Type: image/png
Size: 387713 bytes
Desc: not available
URL: <http://lists.ovirt.org/pipermail/devel/attachments/20140731/9b4ca142/attachment-0006.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: baseline_cpu.png
Type: image/png
Size: 530914 bytes
Desc: not available
URL: <http://lists.ovirt.org/pipermail/devel/attachments/20140731/9b4ca142/attachment-0007.png>