On 10/10/18 2:24 PM, Peter Zijlstra wrote: >> I believe there were some papers circulated last year that looked at >> something similar to this when you had overlapping or completely disjoint >> CPUsets I think it would be nice to drag into the discussion. Has this been >> considered? (if so, sorry for adding line-noise!) > Hurm, was that one of Bjorn's papers? Didn't that deal with AC of > disjoint/overlapping sets? > This paper: https://people.mpi-sws.org/~bbb/papers/pdf/rtsj14.pdf But, unless I am wrong, there were findings after this paper that shows some imprecision on it. Anyway, it does not analyse the locking properties, only scheduler of independent tasks - it is a start, but far from what we do here. (btw this paper is really complex...) The locking problem for such case: APA with the nesting of different locks in the locking implementation (we use raw spin lock on this, and this method could also be used in the rw lock/sem in the future, nesting rw_lock(mutex_proxy(raw_spinlock())) is an open problem from the academic point of view. I explained these things (nested lock and the need of APA for locking) as "Open Problems" at the RTSOPs (part of the ECRTS) earlier this year: http://rtsops2018.loria.fr/wp-content/uploads/2018/07/RTSOPS18_proceedings_final.pdf Bjorn were there, but not only him... Baruah, Davis, Alan Burns were there. There are some works being done for more complex locking in academy, like: https://www.cs.unc.edu/~jarretc/papers/ecrts18b_long.pdf But still, the task model used on these implementations are not the Linux one. -- Daniel
