Bug 1380822

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There is still a bug in Engine that ignores settings of those options for the legacy migration policy and always sends "false" as their values. That has been reported as a separate bug, see https://bugzilla.redhat.com/1383738.

Due to the Engine bug, this Vdsm fix changes migration behavior for the legacy policy: While previously compression and autoconverge were always enabled, they are always disabled now. That should be a good thing for 4.0 as those options are of dubious value with old QEMU, with compression just consuming CPU time.

Verify with:
Engine:Red Hat Virtualization Manager Version: 4.0.5.2-0.2.el7ev
Host:
OS Version:RHEL - 7.3 - 6.el7
OS Description:Red Hat Enterprise Linux Server 7.3 Beta (Maipo)
Kernel Version:3.10.0 - 510.el7.x86_64
KVM Version:2.6.0 - 27.el7
LIBVIRT Version:libvirt-2.0.0-10.el7
VDSM Version:vdsm-4.18.13-1.el7ev
SPICE Version:0.12.4 - 19.el7

Steps to Reproduce:
1. Select legacy migration policy for a cluster and disable migration compression for that cluster.
2. Start a VM in the cluster.
3. Migrate the VM to another host.
4. Check vdsm.log that "compressed" is zero.
Results:
compression is disabled, and compres size is zero.
See log: 
#tail -f /var/log/vdsm/vdsm.log | grep compressed
jsonrpc.Executor/3::DEBUG::2016-10-26 13:55:02,518::__init__::522::jsonrpc.JsonRpcServer::(_serveRequest) Calling 'VM.migrate' in bridge with {u'params': {u'tunneled': u'false', u'dstqemu': u'10.35.117.88', u'autoConverge': u'true', u'src': u'virt-nested-vm14.scl.lab.tlv.redhat.com', u'enableGuestEvents': False, u'dst': u'seal08.qa.lab.tlv.redhat.com:54321', u'vmId': u'6adec1d9-519a-4ca7-b3b6-bae6369777a8', u'abortOnError': u'true', u'compressed': u'false', u'method': u'online'}, u'vmID': u'6adec1d9-519a-4ca7-b3b6-bae6369777a8'}
jsonrpc.Executor/3::DEBUG::2016-10-26 13:55:02,519::API::535::vds::(migrate) {u'tunneled': u'false', u'dstqemu': u'10.35.117.88', u'autoConverge': u'true', u'src': u'virt-nested-vm14.scl.lab.tlv.redhat.com', u'enableGuestEvents': False, u'dst': u'seal08.qa.lab.tlv.redhat.com:54321', u'vmId': u'6adec1d9-519a-4ca7-b3b6-bae6369777a8', u'abortOnError': u'true', u'compressed': u'false', u'method': u'online'}
Thread-139592::INFO::2016-10-26 13:55:16,125::migration::706::virt.vm::(monitor_migration) vmId=`6adec1d9-519a-4ca7-b3b6-bae6369777a8`::Migration Progress: 10 seconds elapsed, 83% of data processed, total data: 1096MB, processed data: 499MB, remaining data: 189MB, transfer speed 52MBps, zero pages: 104922MB, compressed: 0MB, dirty rate: -1, memory iteration: -1

Please note that `compressed:' is always zero during the first memory iteration (there is nothing to compress yet). There should be *at least* two or three memory iterations to actually check for the presence of compressed bytes.

output of migration monitor with compression disabled:
jsonrpc.Executor/0::DEBUG::2016-10-27 10:52:01,953::__init__::530::jsonrpc.JsonRpcServer::(_handle_request) Calling 'VM.migrate' in bridge with {'params': {'tunneled': 'false', 'dstqemu': '10.35.161.161', 'autoConverge': 'false', 'src': 'seal08.qa.lab.tlv.redhat.com', 'enableGuestEvents': False, 'dst': 'virt-nested-vm14.scl.lab.tlv.redhat.com:54321', 'vmId': '2f5a56f5-dcee-4553-a602-e090b6b918aa', 'abortOnError': 'true', 'compressed': 'false', 'method': 'online'}, 'vmID': '2f5a56f5-dcee-4553-a602-e090b6b918aa'}
jsonrpc.Executor/0::DEBUG::2016-10-27 10:52:01,954::API::540::vds::(migrate) {'tunneled': 'false', 'dstqemu': '10.35.161.161', 'autoConverge': 'false', 'src': 'seal08.qa.lab.tlv.redhat.com', 'enableGuestEvents': False, 'dst': 'virt-nested-vm14.scl.lab.tlv.redhat.com:54321', 'vmId': '2f5a56f5-dcee-4553-a602-e090b6b918aa', 'abortOnError': 'true', 'compressed': 'false', 'method': 'online'}
Thread-11438::INFO::2016-10-27 10:52:14,651::migration::712::virt.vm::(monitor_migration) vmId=`2f5a56f5-dcee-4553-a602-e090b6b918aa`::Migration Progress: 9 seconds elapsed, 38% of data processed, total data: 6216MB, processed data: 398MB, remaining data: 3867MB, transfer speed 52MBps, zero pages: 500663MB, compressed: 0MB, dirty rate: 0, memory iteration: 1
Thread-11438::INFO::2016-10-27 10:52:24,653::migration::712::virt.vm::(monitor_migration) vmId=`2f5a56f5-dcee-4553-a602-e090b6b918aa`::Migration Progress: 19 seconds elapsed, 47% of data processed, total data: 6216MB, processed data: 918MB, remaining data: 3348MB, transfer speed 52MBps, zero pages: 500663MB, compressed: 0MB, dirty rate: 0, memory iteration: 1
Thread-11438::INFO::2016-10-27 10:52:34,654::migration::712::virt.vm::(monitor_migration) vmId=`2f5a56f5-dcee-4553-a602-e090b6b918aa`::Migration Progress: 29 seconds elapsed, 81% of data processed, total data: 6216MB, processed data: 1345MB, remaining data: 1242MB, transfer speed 52MBps, zero pages: 931589MB, compressed: 0MB, dirty rate: 0, memory iteration: 1
Thread-11438::INFO::2016-10-27 10:52:44,656::migration::712::virt.vm::(monitor_migration) vmId=`2f5a56f5-dcee-4553-a602-e090b6b918aa`::Migration Progress: 40 seconds elapsed, 89% of data processed, total data: 6216MB, processed data: 1860MB, remaining data: 728MB, transfer speed 52MBps, zero pages: 931589MB, compressed: 0MB, dirty rate: 0, memory iteration: 1
Thread-11438::INFO::2016-10-27 10:52:54,657::migration::712::virt.vm::(monitor_migration) vmId=`2f5a56f5-dcee-4553-a602-e090b6b918aa`::Migration Progress: 50 seconds elapsed, 98% of data processed, total data: 6216MB, processed data: 2377MB, remaining data: 177MB, transfer speed 52MBps, zero pages: 940546MB, compressed: 0MB, dirty rate: 0, memory iteration: 1