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Bug 1279431

Summary:	enable vdsm taskset pinning by default
Product:	[oVirt] vdsm	Reporter:	Michal Skrivanek <michal.skrivanek>
Component:	General	Assignee:	Francesco Romani <fromani>
Status:	CLOSED CURRENTRELEASE	QA Contact:	Lukas Svaty <lsvaty>
Severity:	high	Docs Contact:
Priority:	high
Version:	4.17.11	CC:	bugs, danken, fromani, mkalinin, nsoffer, sbonazzo
Target Milestone:	ovirt-3.6.2	Flags:	michal.skrivanek: ovirt-3.6.z? michal.skrivanek: planning_ack? michal.skrivanek: devel_ack+ rule-engine: testing_ack+
Target Release:	4.17.14
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:	Vdsm cpu pinning is now enabled by default. Vdsm uses the second available CPU in the system, to reduce the traffic on the first one which is often used as default one by other system tasks.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2016-02-18 11:21:47 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	Virt	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	1247075

Description Michal Skrivanek 2015-11-09 13:00:52 UTC

In bug 1247075 we introduced a new cpu_affinity option to pin vdsm threads to a limited number of physical cores to solve a GIL contention on thread scheduling

Testing didn't show any adverse effects, only benefits (improvement is proportional to the size of the host and number of VMs it's running)

Let's enable it by default

Comment 1 Dan Kenigsberg 2015-11-11 09:33:21 UTC

using 'taskset 0' pins Vdsm to the first CPU, which is usually a bit more busy than others. Using 'taskset 1' assume that the host has at least two CPUs. That's true in every real-life scenario. Gil, is it also correct on all QE setups, where virtual hosts are sometime used?

Comment 2 Francesco Romani 2015-11-18 17:01:34 UTC

Please note that http://gerrit.ovirt.org/48619 should take care of this uncommon -but important- cases.

Comment 3 Francesco Romani 2015-11-23 11:40:16 UTC

now really MODIFIED, all patches merged on branch 3.6

Comment 4 Sandro Bonazzola 2015-11-24 16:43:43 UTC

Please set target release or I can't move the bug to ON_QA automatically.

Comment 5 Red Hat Bugzilla Rules Engine 2015-11-24 18:09:06 UTC

Bug tickets that are moved to testing must have target release set to make sure tester knows what to test. Please set the correct target release before moving to ON_QA.

Comment 6 Nir Soffer 2015-11-30 19:30:20 UTC

Should move this to next build.

Comment 7 Michal Skrivanek 2015-12-01 07:16:05 UTC

patch reverted in build 23 onwards, solution moved to 3.6.2

Comment 8 Gil Klein 2016-01-27 10:33:54 UTC

# rpm -qi vdsm
Name        : vdsm
Version     : 4.17.18
Release     : 0.el7ev
Architecture: noarch
Install Date: Wed 20 Jan 2016 06:30:30 PM UTC
Group       : Applications/System
Size        : 3802272
License     : GPLv2+
Signature   : RSA/SHA256, Wed 20 Jan 2016 05:31:13 PM UTC, Key ID 938a80caf21541eb
Source RPM  : vdsm-4.17.18-0.el7ev.src.rpm
Build Date  : Tue 19 Jan 2016 12:34:08 PM UTC
Build Host  : x86-017.build.eng.bos.redhat.com
Relocations : (not relocatable)
Packager    : Red Hat, Inc. <http://bugzilla.redhat.com/bugzilla>
Vendor      : Red Hat, Inc.
URL         : http://www.ovirt.org/wiki/Vdsm
Summary     : Virtual Desktop Server Manager

# grep affinity /var/log/vdsm/vdsm.log 
MainThread::INFO::2016-01-27 09:47:12,758::vdsm::282::vds::(__set_cpu_affinity) VDSM will run with cpu affinity: frozenset([1])