sync TTG to PaRSEC master

[evaleev]

currently TTG master is pinned to a branch in devreal's fork can we re-pin to master? cc: @devreal

[devreal]

Too many fixes in the GPU path that have not been upstreamed yet. MRA is a different beast than large tiles in DPLASMA and it takes too much effort to argue the changes into PaRSEC.

[evaleev]

Too many fixes in the GPU path that have not been upstreamed yet. MRA is a different beast than large tiles in DPLASMA and it takes too much effort to argue the changes into PaRSEC.

We'll have to tackle the "upstream w/ George" challenge at some point.

[devreal]

We're not on the master branch in my fork, but on https://github.com/devreal/parsec-1/tree/parsec-for-ttg.

Features missing in main PaRSEC:

• Support for explicitly discarding device data copies
• Support for allocating host-side data copies on demand
• Improved zone allocator (using red-black tree instead of linear iteration)
• Improvements to the multi-threaded MPI backend
• A bunch of fixes in the device code that gave me grey hairs.

Upstreaming is low priority now. Once the MRA code is working I might revisit this.

[bosilca]

Most of these changes sound reasonable (I have doubts on the MPI multi-threaded). Looking forward to the corresponding PRs.