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Guild: wafer.space Community
Channel: 📐 - Designing / 🕰️-analog / Xyce full-die PEX op-point trials
After: 2026-08-31 11:59 p.m.
Before: 2026-10-01 12:00 a.m.
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[2026-09-30 2:36 a.m.] namibj
WOW was it bad....
I _thought_ it was actually doing stuff in some parallel manner, but it's literally spending a majority of time at least wall-time and possibly even core-time with one of the two MPI processes doing `Xyce::Linear::IfpackPrecond::compute()` and the other one MPI waiting in basically busy loop polling.... yikes.
Gonna try `.options LINSOL USE_IFPACK_FACTORY=1` whcih should use a sparse direct solver on each subdomain, but relies on no singular matrix issues on each subdomain because KLU would fail with that... hmmm.
I guess I should also edit the `.spice` to specifically make it use the `0` net on the substrate which our extraction doesn't model resistance for in hopes of doing so resulting in at least a stronger absence of global coupling entries in the matrices it's trying to use the parallel iterative linear solver(s) on.


[2026-09-30 3:03 a.m.] namibj
gonna re-extract and see then I guess. Like, see how it does with notably relaxed extraction fidelity of the PEX and then ofc setting up Xyce to be more amenable to the situation.


[2026-09-30 6:31 p.m.] namibj
So, shylu_basker works great.
However: I haven't yet figured out how to set it up that specifically only the beret process gets access to one thread on almost all cores (the machine does do other stuff; this soaks up spare CPU cycles!) while the remaining processes get literally just one thread each.

Oh, also `opal` something about openmpi AFAIK somehow manages to do highly wasteful spinlock-seeming activity 🙁
Would have preferred it to manage to use futex like a good linux citizen.....


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