----- Original Message -----
From: "Barak Azulay" <bazulay@redhat.com> To: "Itamar Heim" <iheim@redhat.com> Cc: "engine-devel" <engine-devel@ovirt.org> Sent: Wednesday, June 12, 2013 10:45:25 AM Subject: Re: [Engine-devel] Updates in VdsUpdateRuntimeInfo
----- Original Message -----
From: "Itamar Heim" <iheim@redhat.com> To: "Barak Azulay" <bazulay@redhat.com> Cc: "engine-devel" <engine-devel@ovirt.org> Sent: Wednesday, June 12, 2013 10:09:09 AM Subject: Re: [Engine-devel] Updates in VdsUpdateRuntimeInfo
On 06/12/2013 09:41 AM, Barak Azulay wrote:
----- Original Message -----
From: "Itamar Heim" <iheim@redhat.com> To: "Liran Zelkha" <lzelkha@redhat.com> Cc: "engine-devel" <engine-devel@ovirt.org> Sent: Tuesday, June 11, 2013 4:00:21 PM Subject: Re: [Engine-devel] Updates in VdsUpdateRuntimeInfo
On 06/11/2013 03:26 PM, Liran Zelkha wrote:
Hi all,
I'm checking performance for VdsUpdateRunTimeInfo. Naturally, much of the performance surrounds database activity (getVmsRunningOnVds queries, updateDeviceRuntimeInfo, updateVmDynamic)
Few questions: 1. I have implemented batch updates for procedure UpdateVmDeviceRuntimeInfo for improved performance. 2. Seems like the only parameters UpdateVmDeviceRuntimeInfo is getting are vm_id,vm_device_id,address and alias. Are those rapidly changing, or will it be beneficial to implement caching on those updates (to ensure not-required updates do not travel to the database).
slowly changing, but how will you cover all flows changing these devices to invalidate the cache (iiuc, this table is modified by engine when adding devices to a VM as well?)
I don't think that in the device run time info we need to invalidate once we add a device. This is a specific case where we actually get the information from the VDSM (addresses are received from libvirt) The commands IIRC are first send to VDSM and than update the runtime info only on changed info (we can also hash it), It may put the placeholder in the DB first but it still relies on the data received from VDSM.
if this table is only updated from vdsm to save it, i agree. but isn't the engine also manipulating it? wasn't there a request to be able to maybe edit the addresses some day?
Even if there was such a request, we still update when we receive the info from libvirt.
Anyway there are obviously a few improvements to be done before caching. - update only when info received from VDSM change (need to verify it is the practice here)
This should be the behavior right now There is a hash column in vm_dynamic , this hash is passed by VDSM We are updating only VMs that change their hash value
- do batch update for the new updated data received. - do the hashing (of vm device runtime info) on VDSM for the data , and update only when hash changes - caching ...
Barak
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel