Wednesday, 2025-08-06

auniyalhi sean-k-mooney, will you have access to merge this in nova-disgit 06:36
auniyalhttps://review.rdoproject.org/r/c/openstack/nova-distgit/+/5807606:36
auniyalcan you please provide review comments 06:37
auniyal we have only 1 nova-disgit core -  sahid.ferdjaoui@redhat.com   06:38
auniyalhttps://review.rdoproject.org/r/admin/groups/1abd61acb05653e6333e01582fe4b118a7febc8c,members06:38
auniyalsahid ?06:38
sean-k-mooneyauniyal: i did until october whne i asked to be removed form the list rdo cores for nova. artom and gibi have core rights10:33
sean-k-mooneycurrently the only core right i still have in rdo are for cyborg10:34
sean-k-mooneymelwitt: commeted on the bug10:40
sean-k-mooneyhttps://review.rdoproject.org/r/admin/groups/1abd61acb05653e6333e01582fe4b118a7febc8c,members10:41
sean-k-mooneythat is not the group we use10:41
sean-k-mooneywe use https://review.rdoproject.org/r/admin/groups/d90e2cf3a41ddec7e571c67ce63e10aed1b4e363,members but it looks like artom has not updated that yet to add gibi10:41
sean-k-mooneyanyway this is more a downstream or rdo converstaion since its not really in the scope fo the nova project10:42
auniyalsean-k-mooney ack, 12:06
sean-k-mooneyauniyal: there may be a review open ot update the list12:06
auniyalstill can you please have a look patch is okay 12:06
auniyalI added sahid, hopefully they will look 12:08
sean-k-mooneysahid does not work on this anymore12:08
sean-k-mooneythey may but its unlikely12:08
sean-k-mooneyso the patch shoudl be propsoed againt master first12:09
sean-k-mooneynot direclty to andeploe liek this12:09
sean-k-mooneyand you will need to backprot it in rdo12:09
auniyalyeah I did that first https://review.rdoproject.org/r/c/openstack/nova-distgit/+/5807512:09
sean-k-mooneyright but you abandoned it12:10
auniyalbust as we need this in 18 (downstream) I thought antelope is correct one12:10
sean-k-mooneyso it was not the wrong branch it ned to land there first and then backprot it to antelope12:10
auniyalalso I saw this - https://review.rdoproject.org/r/c/openstack/nova-distgit/+/5775212:10
sean-k-mooneythat is diffent12:11
auniyaloh okay, sure will create the backports then12:11
sean-k-mooneyalthogh it likely shoudl have been done to master first as well12:12
sean-k-mooneythe reason its diffent is the depencies are diffent per branch12:12
mohsen__hello dear friends. Is there anybody here who has ever tested the vCPU vs pCPU performance?12:16
mohsen__I tried NUMATopologyFilter on nova scheduler along with cpu_dedicated_set config on the nova compute side. The scheduling process works completely fine. 12:16
mohsen__this is my nova compute config:12:16
mohsen__[compute]12:16
mohsen__cpu_shared_set = 18-35,54-7112:16
mohsen__cpu_dedicated_set = 0-17,36-5312:16
mohsen__consider the fact that the cpu_shared_set value is on numa node 0 and cpu_dedicated_set is on numa node 1. 12:16
mohsen__The issue is that after creating instances and benchmarking vCPU and pCPU instances separately, the result was surprising. The performance of vCPU was better than pCPU.12:16
mohsen__Is there anybody who has experienced the same issue?12:16
sean-k-mooneythat likely because of other effect related to the numa toplogy12:17
auniyalsean-k-mooney, do you think other things are alight in patch - like file path and bin prefix like nova-contrib - do you have any comment on that12:17
sean-k-mooneyi skimed it and ot look mostly ok but im not sure if you need to set the mode here https://review.rdoproject.org/r/c/openstack/nova-distgit/+/58076/8/openstack-nova.spec#58012:18
sean-k-mooneyit proably should be 755 or 644 but im not sure if that is required12:19
mohsen__sean-k-mooney: What do you mean by other effect? did you mean the other instances on the same compute node can affect the result of the test?12:19
sean-k-mooneyin general this is not somethign i review often so i alwasy have to look up the manpages for install ectra when i do12:20
sean-k-mooneymohsen__: no i mean if the testing your doing is using cinder volume or relys on networking12:20
sean-k-mooneythen using numa node 1 may have higher latency then numa 012:21
auniyalI know it should be executable - I use 755 because that rest of the bins/script has set12:22
sean-k-mooneyim talking about the directory12:22
auniyalinstall -d  --> that mean mkdir -p12:22
sean-k-mooneynot the files 12:22
sean-k-mooneyright which uses the default umask for the current process for the permsions12:23
sean-k-mooneyim not sur eyou shoud be relying on that 12:23
sean-k-mooneyyou likel yshoudl follwo the other exampels where teh mode is alwasy explcitly set12:23
sean-k-mooneyauniyal: all other usage of `install` in that file has an explcity -m to set the mode12:24
sean-k-mooneyso you are deviating form the conventiosn in the file12:24
sean-k-mooneyyou proably shoudl be doing install -d -m 75512:24
sean-k-mooneyhere https://review.rdoproject.org/r/c/openstack/nova-distgit/+/58076/8/openstack-nova.spec#58012:25
auniyalyeah above all setting  permission to dir, 12:26
auniyalI only thought of creating it, then setting chmod to file12:26
auniyalthanks Sean 12:30
mohsen__sean-k-mooney: So how is it possible to have pCPUs with better performance than vCPUs, along with using networking and cinder-volume to create instances?12:31
mohsen__Note that once I changed the cpu_dedicated_set from one numa node to another, and the benchmarking result stayed the same.12:31
sean-k-mooneymohsen__: by the way on an otherwise idel system you are unlikely to see many of the beniftis of pinning. pinning helps performance for 2 reasons., 1 it enfoces a explict numa toplogy so the guest memroy and cpus are allcoated form teh same numa ndoe, (that why you shoudl alwasy set hw:mem_page_size=<some valid value> i.e. small  that give about 70% of the performace boost,12:31
sean-k-mooneythe rest comes form reducign cache misses and prevent other vms form consdume cpu time.12:31
sean-k-mooneymohsen__: tha tis very stragne because in the perfomnance testing we did in the past it did impove performance. the main reasoin for CPU pinning is not raw trhoughput however, it benifit is in determinisum12:33
sean-k-mooneyit shoudl not reduce the performce vs vcpus becasue the emulation of the vcpu is identical12:33
sean-k-mooneyall cpu pinnign does is use cgroups/taskset to prevent the kernel form movinv the cpus12:34
sean-k-mooneyand on the nova side we prevent other vms form beign schduled to the same cores12:34
sean-k-mooneyits why we call it cpu_policy=dedicated12:34
sean-k-mooneyyou care giveing an entire host cpu to the vm provide you are isolating other host process form those cores 12:35
sean-k-mooneyregarding newtwokrign and cidner , if your using sriov you can allcoat vfs form the local numa node  or you can use a cross numa bond for the stroage network12:35
sean-k-mooneymohsen__: when you swap the numa nodes did you delete and recreate the vms by the way12:36
opendevreviewRajesh Tailor proposed openstack/nova master: Add support for using cell-name in cell_v2 commands  https://review.opendev.org/c/openstack/nova/+/95446012:48
mohsen__sean-k-mooney: Yes. I removed the old instances and after reconfiguration, created new ones. So you mean cpu performance improvement isn't necessarily the benefit of cpu pinning?12:50
mohsen__having such an expectation isn't always valid? 12:50
sean-k-mooneycpu pinning was create to provide predicable perfroamce under load13:25
sean-k-mooneyit often provides mroe performce as a side effect of enfoceign numa affintiy between guest cpus ram and pci devices13:25
sean-k-mooneybut most of the uplift comes enableing numa affintiy as cpu pinning implictly enables hw:numa_nodes=113:29
sean-k-mooneyadding hw:numa_nodes=1 hw:mem_page_size=small13:30
sean-k-mooneyyou will get most of the performace uplift that is expect form cpu pinnin for floating guests13:30
opendevreviewIan Watson proposed openstack/nova master: Add migration conditional for resource tracker  https://review.opendev.org/c/openstack/nova/+/95569014:09
sean-k-mooneystephenfin: also interesting error in the logs https://paste.opendev.org/show/bxMqpRogUlo3jHCe2trb/ that likely related to your volume bug14:24
sean-k-mooneywe shoudl be able to catch that and abort starting the agent and let systemd or whatever restart it14:24
stephenfinooohh, good spot14:24
sean-k-mooneyhttps://0908e5c3034094a51a1a-ddb50bb0d8d4f5453b9288f160ef0a30.ssl.cf5.rackcdn.com/openstack/70be4003a0ae40b4bfaae667688f694c/controller/logs/screen-n-cpu.txt14:25
sean-k-mooneyits right in the startup just after the config is printed14:25
sean-k-mooneyso it pretyy early14:25
sean-k-mooneybut my guess is it never recovers form that if it happens14:25
sean-k-mooneyso either we need to abort or retry14:25
sean-k-mooneywell or something more indelgent then the 30s tought i have given it14:26
sean-k-mooneycan you see if you have the same error in your logs if you have time14:26
sean-k-mooneystephenfin: https://tinyurl.com/yw5ynd7d14:28
sean-k-mooneyits happening alot in the usptream jobs14:29
stephenfinyes, I see it in the flamingo VM. I don't see it in the bobcat VM14:29
sean-k-mooneyacross c9s ubuntu and debian14:29
stephenfinand I've since deleted all the other VMs14:29
sean-k-mooneyack14:29
sean-k-mooneyso that likely the problem14:29
sean-k-mooneyi dont know what the cause iss but thats a smoking gun14:29
sean-k-mooneyi.e. i dont knwo why it does not happen after restarting nova-comptue but apprently it does not always fail14:30
stephenfinsean-k-mooney: dumped it into the bug https://bugs.launchpad.net/nova/+bug/2119114/comments/314:33
sean-k-mooneycool i didnt have the link to that14:33
* stephenfin wishes they'd add markdown support (or at least code fence support) to LP...14:33
noonedeadpunk++15:12
cardoesean-k-mooney: so not sure if you saw my follow up on the vlan spec. The issue you pointed out in chat about the id field and that dansmith brought up on gerrit itself isn't something that spec can really fix right now. It's just defining the behavior of nova code today (and the behavior that its been since June 2015).15:24
cardoeSo I'm really not sure what to fix cause that spec isn't about changing the behavior of existing "phy" interfaces. It's about including "vlan" interfaces. The "vlan" interface references to "phy" interface its running on.15:25
sean-k-mooneythe spec si free to extend or modify the schema and change the data that is stored in specific fileds15:26
sean-k-mooneyit is not possibel for nova ot know what the name of the Phy interface will be15:26
sean-k-mooneyso the value that are provdie are and alwasy were informational15:26
sean-k-mooneyyou are ment ot match on things like the mac adress15:27
sean-k-mooneywhen you are consumign this to identify the phy not the id or name15:27
sean-k-mooneyits just an identifyer for the parsing program15:27
abhishekko/ can I get a review on https://review.opendev.org/c/openstack/nova/+/950623, it has one +2, this will be important change to get rid of show_multiple_locations config option15:29
noonedeadpunkfwiw, I've addressed comments in https://review.opendev.org/c/openstack/nova-specs/+/955783 and I think implementation is also available for preliminary review15:38
melwittthanks sean-k-mooney 15:45
sean-k-mooneyabhishekk: does it work this time? :) if i recall we reverted it because there was soem issue on the glance side that needed to be adressed first15:47
sean-k-mooneyabhishekk: ah i see dan is already +2 that reverting the revert15:47
sean-k-mooneyill take a look shortly15:48
sean-k-mooneywe can always have a revert^3 patch if needed i guess.15:48
abhishekksean-k-mooney: thank you!!! I have added rechecks 7-8 times on revert patch to ensure that failure does not occur again16:48
sean-k-mooneynoonedeadpunk: oh the parallel mgtions17:08
sean-k-mooneywe really need to create teh 2026.1 folder in the specs repo17:08
sean-k-mooneyso you can propose that to the right pplace17:08
sean-k-mooneynoonedeadpunk: ill try and loop back to that but it likely will be next week at this rate17:09
opendevreviewStephen Finucane proposed openstack/nova master: api: Add response body schemas for servers APIs (1/6)  https://review.opendev.org/c/openstack/nova/+/95623417:15
opendevreviewStephen Finucane proposed openstack/nova master: api: Add response body schemas for servers APIs (2/6)  https://review.opendev.org/c/openstack/nova/+/95623617:15
opendevreviewStephen Finucane proposed openstack/nova master: api: Add response body schemas for servers APIs (3/6)  https://review.opendev.org/c/openstack/nova/+/95623717:15
opendevreviewStephen Finucane proposed openstack/nova master: api: Add response body schemas for servers APIs (4/6)  https://review.opendev.org/c/openstack/nova/+/95623817:15
opendevreviewStephen Finucane proposed openstack/nova master: api: Add response body schemas for servers APIs (5/6)  https://review.opendev.org/c/openstack/nova/+/95623917:15
opendevreviewStephen Finucane proposed openstack/nova master: api: Add response body schemas for servers APIs (6/6)  https://review.opendev.org/c/openstack/nova/+/95624017:15
opendevreviewStephen Finucane proposed openstack/nova master: api: Add response body schemas for server shares APIs  https://review.opendev.org/c/openstack/nova/+/95626617:15
opendevreviewStephen Finucane proposed openstack/nova master: tests: Invert validation check  https://review.opendev.org/c/openstack/nova/+/95624117:15

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