This is the mail archive of the libc-alpha@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [RFC] Dynamic lock elision support


On Fri, Aug 28, 2015 at 04:27:57PM -0500, Steven Munroe wrote:
> On Tue, 2015-08-18 at 16:58 -0500, Paul E. Murphy wrote:
> > Was any consensus reached regarding adding environment variables for
> > tuneables? The only alternative I've seen floated is to use HWCAP bits to
> > point to a separate variant of libpthread. It seemed more undesirable.
> > 
> > I like Andi's approach, and am willing to rework and resubmit Andi's
> > patchset for the remaining archs if there is agreement with his approach.
> > 
> > I think we would all benefit from a runtime mechanism to transition
> > into TLE while we work to best utilize this new tool.
> > 
> How do we move this forward and who needs to be brought into the
> consensus?

Hi Steven,

I posted the patch a few times, but noone reviewed it. I guess it mainly
needs reviewers.

Yes tuning ability is very important for elision.

When the tuning was originally discussed Roland didn't like it. However
I later discussed it with him privately and I addressed all his
points (by adding a white list) for the environment tuning.
That was implemented in my latest patchkits.

There was unfortunately no consensus on a real run time tuning
capability for the program (other than turning it off by changing
the mutex type). I know some people do it by patching the mutex
structures though.

BTW I also have a hack to patch it through LD_PRELOAD, but yes
an official interface would be better.

-Andi


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]