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Subject: Meeting tomorrow, notes for March 25 meeting
From: Hans Boehm (boehm_at_[hidden])
Date: 2019-04-28 23:00:21
We are meeting tomorrow April 29th at noon PDT, usual coordinates:
Join Hangouts Meet
meet.google.com/sbj-cvgh-vnd
Join by phone
‪+1 208-925-0196‬ PIN: ‪255 542‬#
The topic will continue to be the TM-lite proposal.
Notes from March 25:
-----------------------------
Attendees: Jade Alglave, Hans Boehm, Michael Scott, Michael Spear, Victor
Luchangco
Discussed Victor's additions to
M Spear: Synchronized instead?
Victor: No, want atomic block.
M Spear: Want to be able to use STL, e.g. map in transaction.
Hans: trade-off, non constexpr makes it implementation defined
Victor: Want nested transactions
M Spear: Should allow proper software engineering in transactions.
Victor: Should look at what's really allowed in constexpr.
M Spear: Want everything visible in translation unit to be allowed.
Hans : trade-off against portability. Constexpr growing.
M Spear: Not for simplifying implementation. Single global lock always
works.
All: Aim for subset of atomic_noexcept.
Do we need to catch transaction-unsafe code that's never executed?
Hans: Previously decided on undefined behavior when executing
transaction-unsafe code.
M Scott: Is SGL with no checks conforming?
Allow either detection or simple SGL?
M Spear: Real challenge is getting users. This is simpler than existing
implementations.
M Scott: 2 possible implementations:
HTM-centric plus diagnosis
SGL with no diagnosis
M Scott: Should warn, but not for atomics
M Spear: Should prohibit volatile, atomics, inline assembly
Victor: What about IO?
M Scott: Don't want to require diagnosis for unexecuted code.
Jade: Lock-free?
Victor: Want to allow SGL for now
Meet next time as scheduled, on April 29.
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