| Posted | Nick | Remark | |
|---|---|---|---|
| #openstack-nova - 2022-06-14 | |||
| 10:51:30 | sean-k-mooney | https://github.com/SeanMooney/cpu-pinning/blob/master/pinning.py#L378-L415= | |
| 10:52:25 | sean-k-mooney | the issue with my alternitiv implemntation is it only supprots hugepages and cpu pinning | |
| 10:52:36 | sean-k-mooney | it is missing pci supprot and mixed cpu support | |
| 10:53:48 | sean-k-mooney | ill run there repodcuer to have a comparison on the same hardware | |
| 10:59:21 | sean-k-mooney | im going to make coffee whiel this runs... | |
| 11:03:42 | gibi | dansmith, bauzas: what do you think do we want to / can do something about this? https://bugs.launchpad.net/nova/+bug/1978549 It feels like a bug but I'm not sure I want to go back and add a db migration to stein in nova or touch the placement db init script. https://bugs.launchpad.net/nova/+bug/1978549 | |
| 11:06:20 | sean-k-mooney | gibi: dont we tend to not drop the columes right away | |
| 11:06:29 | sean-k-mooney | to cater for rolling upgrades | |
| 11:06:48 | gibi | sure | |
| 11:06:52 | sean-k-mooney | we stop the usage and then a few release later we can drop the column | |
| 11:07:01 | gibi | but then we suddenly forget to add it to the placement db init script | |
| 11:07:27 | gibi | so if you have a DB that was created before placemetn was moved out of nova repor then you have can_host | |
| 11:07:35 | sean-k-mooney | well that woudl only be an issue if you were initing on a version that used it right | |
| 11:08:23 | gibi | we removed the can_host column but without a DB migration | |
| 11:08:38 | gibi | the removal happen when the new db init was created for the moved out placement | |
| 11:08:46 | sean-k-mooney | i see | |
| 11:10:18 | sean-k-mooney | gibi: real 12m32.814s | |
| 11:10:38 | sean-k-mooney | maybe my 4 year old laptop is starting to show its age | |
| 11:11:55 | sean-k-mooney | gibi: we could just document this as a workaround for the db issue | |
| 11:12:27 | sean-k-mooney | the fix is only requried if movign form in nova to out of tree placement right | |
| 11:12:40 | sean-k-mooney | if you are doign a db restore | |
| 11:12:48 | sean-k-mooney | and even then only if you are migrating db backends | |
| 11:13:16 | sean-k-mooney | if you were just doing a db export and import in mysql it would be fien because the improt would create the tabels | |
| 11:13:46 | sean-k-mooney | in there case they likely are just migrating the data and using placemnt-mange to init an empty db | |
| 11:16:08 | gibi | I agree to only document the workaround. I'm not sure where to put that documentation though. As adding a reno now in zed in placement for an issue introduced in stein in nova does not feels right | |
| 11:16:49 | sean-k-mooney | we can do a stable only reno | |
| 11:16:59 | sean-k-mooney | on stine | |
| 11:17:48 | sean-k-mooney | or update the existing one for speliting out placment which i assuem exists somewhere | |
| 11:18:00 | gibi | hm there is admin/upgrade-to-stein.rst | |
| 11:18:11 | gibi | that would be OK | |
| 11:18:13 | gibi | thanks | |
| 11:32:45 | opendevreview | Balazs Gibizer proposed openstack/placement master: Add WA about resource_providers.can_host removal https://review.opendev.org/c/openstack/placement/+/845730 | |
| 11:33:10 | sean-k-mooney | gibi: im not going to do this now but if i were to update my poc to implemetne all or a subset of the current numa_fit_instance_to_host funciton | |
| 11:33:59 | sean-k-mooney | would we consider that backportable if it was opt in and both implemations could be in the code in parallel even fi only one would be used on a compute host at a time | |
| 11:34:26 | gibi | why we need both? does yours produce a different result than the current? | |
| 11:34:41 | sean-k-mooney | mine does not do everythin the current one does | |
| 11:34:59 | gibi | yepp, then we might need a config flag | |
| 11:35:04 | sean-k-mooney | so im wondering if we coudl make it incremental | |
| 11:35:40 | sean-k-mooney | and also have the option to run both as filters | |
| 11:35:55 | sean-k-mooney | so mine currently only handeles hugepages and cpu pinning | |
| 11:36:17 | sean-k-mooney | its missing pci devices and mixed cpus and maybe pmem | |
| 11:36:38 | sean-k-mooney | pmem enabels a numa toplogy but i dont think we provide affintiy for pmem | |
| 11:36:57 | sean-k-mooney | so its reall just mixed mode and pci devices that woudl initally be missing | |
| 11:37:38 | sean-k-mooney | my tought is you coudl enable both filters and have the fast one run first so you woudl only validate the slow hosts if we knew the cpu and ram request were valid | |
| 11:38:07 | sean-k-mooney | s/slow hosts/hosts with the slow version/ | |
| 11:38:32 | gibi | overall I'm OK to make it incremental or even selectable, but I'm not sure stable cores will like it | |
| 11:38:51 | gibi | this will include a new bounch of code to stable branches | |
| 11:38:54 | sean-k-mooney | so basicaly you woudl do pci_passthroughfilter,numa_v2,numa_toplogy_filter | |
| 11:39:01 | gibi | that is liability | |
| 11:39:09 | sean-k-mooney | yep | |
| 11:39:12 | sean-k-mooney | it is | |
| 11:39:34 | gibi | what if we just add what we have to master as selectable, then we improve on it later on master | |
| 11:39:50 | sean-k-mooney | we could yes | |
| 11:40:07 | sean-k-mooney | im just trying to think if there is anything we can do to adress the bug report on older branches too | |
| 11:40:52 | sean-k-mooney | i dont think there is anythign trivial that can be fixed on the older brances to make the perfromance accpetabel. | |
| 11:41:39 | gibi | I don't know. maybe we can look at the reproducer in a profiler | |
| 11:42:11 | sean-k-mooney | i think its to do with our usage so itertools permuations | |
| 11:42:33 | sean-k-mooney | we do a liniar loop over all permuations of numa nodes when trying to fit the instance | |
| 11:43:06 | sean-k-mooney | we early out once the instance fits but that is really not efficent with more then a hand full of numa nodes | |
| 11:44:37 | sean-k-mooney | gibi: i can try an take a look at it breifly | |
| 11:45:11 | gibi | sean-k-mooney: only if you want :) I'm not asking to take this | |
| 11:45:29 | gibi | I'm not promising either that I can fire up a profiler today | |
| 11:45:36 | sean-k-mooney | hehe | |
| 11:45:44 | sean-k-mooney | this is not new | |
| 11:46:01 | sean-k-mooney | so i dont think it supper high priority but i was half way thorugh fixing up my vdpa patches | |
| 11:46:07 | sean-k-mooney | so i want to finish those today | |
| 11:46:30 | sean-k-mooney | so im somehwat interested in is there a minimal fix we can do to make ti better | |
| 11:46:39 | sean-k-mooney | i just dont want to spend all day looking at it | |
| 11:46:48 | sean-k-mooney | so ill give it tilll the top of the hour | |
| 11:47:07 | sean-k-mooney | we can take another look later in the week or next week | |
| 11:47:36 | gibi | ack | |
| 11:57:21 | opendevreview | Merged openstack/nova stable/wallaby: Add service version check workaround for FFU https://review.opendev.org/c/openstack/nova/+/844202 | |
| 11:59:05 | gibi | :) | |
| 11:59:41 | sean-k-mooney | its amazing how much simpler nova code becomes without eventlets | |
| 12:01:11 | sean-k-mooney | actully there might be a small tweak we can do | |
| 12:02:08 | sean-k-mooney | we currently do this | |
| 12:02:10 | sean-k-mooney | for host_cell_perm in itertools.permutations( | |
| 12:02:12 | sean-k-mooney | host_cells, len(instance_topology) | |
| 12:02:14 | sean-k-mooney | ): | |
| 12:02:26 | sean-k-mooney | so we get the next perumation for the full pinning | |
| 12:02:47 | sean-k-mooney | i wonder if we could do this one numa node at a time | |
| 12:03:10 | sean-k-mooney | so loop over the instnace numa cells | |
| 12:03:33 | sean-k-mooney | and try to pin them one at a time | |
| 12:03:36 | sean-k-mooney | then try to pin the rest | |
| 12:04:04 | sean-k-mooney | i think that would be a lot faster | |
| 12:04:36 | sean-k-mooney | as currently if the first 7 numa nodes are full we have to try all permuations for the 7 numa nodes before we will try the 8th i think | |
| 12:05:37 | sean-k-mooney | if i refactor this we will do 7 test for the first guest numa node it will match on the 8th numa node and then we will try fiting the next numa node | |
| 12:05:48 | gibi | would that just do the permutation generation with loops? sure the order of the search would be different | |
| 12:06:10 | gibi | so it might optimize for the current csae | |
| 12:06:11 | gibi | case | |
| 12:06:31 | sean-k-mooney | the worst case performace woudl still be the same but i think it would imporve best and average case | |
| 12:11:03 | gibi | so we optimize based on some heuristics that the first numa nodes are more likely to be filled than the later numa nodes | |
| 12:11:24 | sean-k-mooney | well until master it did a liniar search | |
| 12:11:37 | sean-k-mooney | so yes the first numa nodes were always filled first deterministically | |
| 12:11:51 | sean-k-mooney | we recently added numa node blancing | |
| 12:12:22 | gibi | true, so using the old linear fill, it make sense to add a heuristics to the search to | |
| 12:12:25 | gibi | o | |
| 12:12:44 | sean-k-mooney | also my entire system just hard locked up while i was debuging that even with it paused | |
| 12:12:51 | gibi | wondering if just simply using permutations(reversed(host_cells)) would be enough to optimize too | |
| 12:12:53 | sean-k-mooney | perhaps i should close some broser tabs | |