Re: [PATCH 0/3] Improve ARM atomic performance for malloc

[Will Newton <will dot newton at linaro dot org>]

On 6 October 2014 14:31, Torvald Riegel <triegel@redhat.com> wrote:
> On Fri, 2014-10-03 at 16:27 +0000, Joseph S. Myers wrote:
>> On Fri, 3 Oct 2014, Will Newton wrote:
>>
>> > The resulting atomic.h is hopefully somewhere close to a generic
>> > implementation based on the gcc intrinsics so could potentially
>> > be used as a base for a generic header.
>>
>> That suggests to me that the starting point should be setting up a generic
>> header that can be used for multiple architectures and making the ARM
>> header inherit from it in the case where the relevant compiler support is
>> available, rather than putting all this generic code in an ARM header.
>> (And in turn, the starting point in the generic header could be the
>> particular operations for which more or less generic code already exists
>> in the ARM header, with other operations added to it later.)
>
> I agree.
>
> In addition, I think that the best step to do this would be when we
> switch to C11-like atomics because with this switch, this falls out kind
> of naturally.
>
> Will, have you looked at my suggestion and the POC patch I posted for
> how C11-like atomics could look like?  I won't get to continue to work
> on this topic this week, but it's still on my agenda.

It's interesting, and long term seems like the best way of doing
things. However I do not see any viable chance of that work being
completed for 2.21. Do you have a timescale in mind? It seems we would
need to convert all uses of the atomic API and all the architecture
ports.

-- 
Will Newton
Toolchain Working Group, Linaro