WeeklyTelcon_20200616

Open MPI Weekly Telecon ---

Schedule: Want to release mid-July
- RC1 planned for Monday, 8 July, 2020
Release Engineers: Brian (AWS) Jeff Squyres (Cisco)
We've come to consensus for a v4.1.0 release
- Not breaking ABI or backwards compatibility.
- Blocker moving forward is to start from the v4.0.4 tag (Tomorrow)
- NOT touching runtime!!!
- Not going to be pulling in a new PMIx version.
Next Steps: MTT testing needs to come online
- Ciscos already online last night.
- IBM will get it online tonight.
- AWS will get it online tonight as well.
- Mellanox - will come online tomorrow night

v4.0.4 Released last week.
Where do we stand with the memory hooks for Open MPI Memory patcher?
- Save/restore of r2 on ppc64le only.
- Not sure which component use these memory patcher
  - OpenIB uses Open MPI memory patcher. Not in master, only in v4.0.x
  - 7799 is still open against master.
v4.0.5 - No schedule yet.

Need to put OSC pt2pt
- OS RDMA requires a single BTL that can contact every single process.
  - This didn't use to be the case. (Comment in the code)
We can't use the OSC pt2pt.
- It is not thread safe. Doesn't conform to MPI4 standard. Not safe.
- This is just a testing falicy. Could add tests to show this, but still at same boat.
- Either product A or B is broken and we need to fix it.
RDMA Onesided should fall back to "my atomics" because TCP will never have rdma atomics.
- The idea was to put the atomics into the BTL base, which could do all of the one-sided atomics under the covers.
Jeff will close the PR, and
Jeff will Nathan will fetching, get, compare and swap.
Does UCX support iWarp?
- Does libFabric support iWarp via verbs provider?
- https://github.com/openucx/ucx/issues/2507 suggest it doesn't.
- Brian thinks that libFabric
- OFI can support iWarp, just need to specify the provider in the include list.
- This person who's asking is a partner not a customer
PMIX
- Working on PMIx v4.0.0 which is what Open MPI v5.0 will use.
- PPN scaling issue - simple algorithmic issue in this function
  - PMIX talked about it. Artem might know someone who might be interested in working on it.
  - Algorithm behind one of the interfaces doesn't scale well.
  - Not a regression. Above ~ 4K nodes, becomes quadratic.
PRRTE *
Two new PRs for MPI4.0 Error handling - new PRs from Aurelien Bouteiller. *

UCX is failing in certain test cases, SEGV
- Austen will open an issue.
PRRTE is hitting and assert in some cases.
- Austen will Open Issue
Remaining CISCO failures look like connectivity issues.
- Jeff hasn't got to look deeper to see
- Looks like USNIC is either not being picked or disqualifying itself internic.
CLANG - added float16
- Need to add a special compiler flag for software emulation of float16.
- Not magically add that flag.

Many companies are not allowing a face to face travel until 2021 due to COVID19.
- Instead lets do a series of virtual-face to face?
Yes this summer to discuss for v5.0
- Maybe we can do it by topic?
- Maybe not 4 or 8 hour things.
Different topics on different days.
Do a doodle poll of least-worse days in late July/August.
Start a list of topics.

May not have Super Computing conference at ALL this year.
Many other projects are doing a virtual state of the union type meeting to try to cover what they'd usually do in a Birds of a feather meeting.
Then this works pretty well, and do this a couple of times a year.
Not constrained to Super Computing