Change in vdsm[master]: vm: get rid of BoundedSemaphore around libvirt

Francesco Romani has uploaded a new change for review.

Change subject: vm: get rid of BoundedSemaphore around libvirt
......................................................................

vm: get rid of BoundedSemaphore around libvirt

in the VM creation flow, we had a BoundedSemaphore
to throttle libvirt access and avoid congestion.
The ultimate purpose is to perform better.

However, since at least libvirt 0.10.x, avoiding
this semaphore leads to better performance.

Libvirt has more scalability improvement implemented
in later versions or planned, so this will improve
even further in the future.

Change-Id: I8a2038eadccee045e72dcf90cefe93286dab273b
Relates-To: https://bugzilla.redhat.com/861918
Signed-off-by: Francesco Romani <fromani(a)redhat.com&gt;
---
M vdsm/vm.py
1 file changed, 0 insertions(+), 6 deletions(-)


  git pull ssh://gerrit.ovirt.org:29418/vdsm refs/changes/57/25857/1

diff --git a/vdsm/vm.py b/vdsm/vm.py
index c53f1d4..560ea32 100644
--- a/vdsm/vm.py
+++ b/vdsm/vm.py
@@ -1914,7 +1914,6 @@
     """
     log = logging.getLogger("vm.Vm")
     # limit threads number until the libvirt lock will be fixed
-    _ongoingCreations = threading.BoundedSemaphore(4)
     DeviceMapping = ((DISK_DEVICES, Drive),
                      (NIC_DEVICES, NetworkInterfaceDevice),
                      (SOUND_DEVICES, SoundDevice),
@@ -2300,8 +2299,6 @@
         self.log.debug("Start")
         try:
             self.memCommit()
-            self._ongoingCreations.acquire()
-            self.log.debug("_ongoingCreations acquired")
             self._vmCreationEvent.set()
             try:
                 self._run()
@@ -2316,9 +2313,6 @@
                     raise
                 else:
                     self.log.info("Skipping errors on recovery",
exc_info=True)
-            finally:
-                self._ongoingCreations.release()
-                self.log.debug("_ongoingCreations released")
 
             if ('migrationDest' in self.conf or 'restoreState' in
self.conf) \
                     and self.lastStatus != 'Down':


-- 
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Gerrit-MessageType: newchange
Gerrit-Change-Id: I8a2038eadccee045e72dcf90cefe93286dab273b
Gerrit-PatchSet: 1
Gerrit-Project: vdsm
Gerrit-Branch: master
Gerrit-Owner: Francesco Romani <fromani(a)redhat.com&gt;

Itamar Heim has posted comments on this change.

Change subject: vm: get rid of BoundedSemaphore around libvirt
......................................................................


Patch Set 1:

ping

-- 
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Gerrit-MessageType: comment
Gerrit-Change-Id: I8a2038eadccee045e72dcf90cefe93286dab273b
Gerrit-PatchSet: 1
Gerrit-Project: vdsm
Gerrit-Branch: master
Gerrit-Owner: Francesco Romani <fromani(a)redhat.com&gt;
Gerrit-Reviewer: Douglas Schilling Landgraf <dougsland(a)redhat.com&gt;
Gerrit-Reviewer: Francesco Romani <fromani(a)redhat.com&gt;
Gerrit-Reviewer: Itamar Heim <iheim(a)redhat.com&gt;
Gerrit-Reviewer: automation(a)ovirt.org
Gerrit-Reviewer: oVirt Jenkins CI Server
Gerrit-HasComments: No

[Jenkins CI RO]

oVirt Jenkins CI Server has posted comments on this change.

Change subject: vm: get rid of BoundedSemaphore around libvirt
......................................................................


Patch Set 1:

Build Successful 

http://jenkins.ovirt.org/job/vdsm_unit_tests_gerrit_el/6695/ : SUCCESS

http://jenkins.ovirt.org/job/vdsm_master_pep8_gerrit/7486/ : SUCCESS

http://jenkins.ovirt.org/job/vdsm_unit_tests_gerrit/7596/ : SUCCESS

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Gerrit-MessageType: comment
Gerrit-Change-Id: I8a2038eadccee045e72dcf90cefe93286dab273b
Gerrit-PatchSet: 1
Gerrit-Project: vdsm
Gerrit-Branch: master
Gerrit-Owner: Francesco Romani <fromani(a)redhat.com&gt;
Gerrit-Reviewer: automation(a)ovirt.org
Gerrit-Reviewer: oVirt Jenkins CI Server
Gerrit-HasComments: No

Francesco Romani has abandoned this change.

Change subject: vm: get rid of BoundedSemaphore around libvirt
......................................................................


Abandoned

will be resumed once properly benchmarked.

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Gerrit-MessageType: abandon
Gerrit-Change-Id: I8a2038eadccee045e72dcf90cefe93286dab273b
Gerrit-PatchSet: 1
Gerrit-Project: vdsm
Gerrit-Branch: master
Gerrit-Owner: Francesco Romani <fromani(a)redhat.com&gt;
Gerrit-Reviewer: Douglas Schilling Landgraf <dougsland(a)redhat.com&gt;
Gerrit-Reviewer: Francesco Romani <fromani(a)redhat.com&gt;
Gerrit-Reviewer: Itamar Heim <iheim(a)redhat.com&gt;
Gerrit-Reviewer: automation(a)ovirt.org
Gerrit-Reviewer: oVirt Jenkins CI Server