Re: TSX lock elision for glibc v14

["Carlos O'Donell" <carlos at redhat dot com>]

On 06/28/2013 04:25 AM, Carlos O'Donell wrote:
> On 06/28/2013 01:51 AM, Andi Kleen wrote:
>> All open issues addressed. Should be (hopefully) ready for merging now.
> 
> I've reviewed patches 1 through 9.
> 
> Patches 1 through 9 are almost 100% non-ABI / non-API,
> and with minor work we can make them clean.
> 
> I would like Torvald and Rich to comment on patch #5
> to confirm that my interpretation is a defensible
> position for rwlock.

Patch #5 is still outsanding and needs consensus.

I would seem that Andi and I agree that POSIX is sufficiently
flexible to allow an elided rwlock.

I'm looking for feedback on my comments.

> I would like to see a v2 of patch 6 with tests for
> the new interfaces moved to the patch that adds the
> interface (patch #11).

Andi is reworking patch 6 to include a minimal set of
changes to ensure the existing testsuite runs cleanly.

> I would like to see patch 8 reworked slightly again
> to move the new interface documentation into the patch
> that adds the new interface (patch #11).

I've provided Andi with an incremental patch to cleanup
the documentation and I've indicated my intent to help
check this in if he's out of time.

I really want to drive these last 3 issues to completion
so we can get a baseline elision framework in place.

A baseline framework in 2.18 is important in that:

* It will reduce the work needed for a distro to enable
  elision usefully for their experimental users.

* It will prevent fragmented and varied patches at the
  distro level. We've already found several defects
  with the elision support that will propagate to the
  distros if we have baseline support.

* It will simplify the review of future patches that
  depend upon the baseline support.

Cheers,
Carlos.