Malloc improvements

[Florian Weimer]

On 07/14/2016 01:49 PM, Anton Blanchard wrote:
> Hi Florian,
>
>>> It's great to see the current focus on improving malloc. One thing
>>> that would really help POWER is reducing the number of locks and
>>> atomics in the fast path. Right now we have 3 in the malloc
>>> fastpath and 2 in free. These add up.
>>
>> Does the hook variable read count as an atomic operation in this
>> sense?
>
> The read hook shouldn't be. The atomic issue I was referring to was
> something we've been trying to solve for a while:
>
> https://sourceware.org/ml/libc-alpha/2014-05/msg00118.html

x86_64 checks __libc_multiple_threads and avoids atomics if possible. 
Do you already do this in POWER?

Thanks,
Florian