Re: [PATCH] malloc: Use correct C11 atomics for fastbin

[Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>]

On 06/12/22 10:29, Wilco Dijkstra via Libc-alpha wrote:
> Hi,
> 
> On 2022-12-02 1:55 PM, DJ Delorie via Libc-alpha wrote:
>>> Wilco Dijkstra <Wilco.Dijkstra@arm.com> writes:
>>>> If we want to make tcache actually work, it will have to support far more
>>>> allocations, particularly for smaller sizes.
>>>
>>> You can test that with a tunable; the max count per bin is runtime
>>> tunable.
> 
> Yes you can use tunables, but how many applications actually use more
> optimized settings? It's the default that is the problem.
> 
>>> But yeah, the point of tcache is to have a few of many sizes for fast
>>> allocations.  Fastbins has a lot of a few small sizes.  Testing showed
>>> that both were required for best performance with the average
>>> application.
> 
> Yes, that's due the tiny size of tcache (let's call it tiny-cache!). Once exhausted,
> you mostly end up using the fastbins.
> 
>> Every time we start talking about fastbins vs tcache again I start 
>> wondering, again, what's stopping us from replacing the entire malloc 
>> implementation with jemalloc, or any other implementation designed less 
>> than 20 years ago.
> 
> I can't see any technical reason why not. It's either that or completely rewriting
> the current implementation and getting rid of decades of accumulated cruft...
> 
> Modern allocators are not only much faster than GLIBC in their default settings
> but also have lower memory usage. The two best allocators seem to be mimalloc
> and jemalloc.


Do they have compatible license so we can just import/adapt the code?