Re: [PATCH v9 1/5] lib: objpool added: ring-array based lockless MPMC

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Hi Wuqiang,

On Tue,  5 Sep 2023 09:52:51 +0800
"wuqiang.matt" <wuqiang.matt@xxxxxxxxxxxxx> wrote:

> The object pool is a scalable implementaion of high performance queue
> for object allocation and reclamation, such as kretprobe instances.
> 
> With leveraging percpu ring-array to mitigate the hot spot of memory
> contention, it could deliver near-linear scalability for high parallel
> scenarios. The objpool is best suited for following cases:
> 1) Memory allocation or reclamation are prohibited or too expensive
> 2) Consumers are of different priorities, such as irqs and threads
> 
> Limitations:
> 1) Maximum objects (capacity) is determined during pool initializing
>    and can't be modified (extended) after objpool creation
> 2) The memory of objects won't be freed until objpool is finalized
> 3) Object allocation (pop) may fail after trying all cpu slots

I made a simplifying patch on this by (mainly) removing ages array.
I also rename local variable to use more readable names, like slot,
pool, and obj.

Here the results which I run the test_objpool.ko.

Original:
[   50.500235] Summary of testcases:
[   50.503139]     duration: 1027135us 	hits:   30628293 	miss:          0 	sync: percpu objpool
[   50.510416]     duration: 1047977us 	hits:   30453023 	miss:          0 	sync: percpu objpool from vmalloc
[   50.517421]     duration: 1047098us 	hits:   31145034 	miss:          0 	sync & hrtimer: percpu objpool
[   50.524671]     duration: 1053233us 	hits:   30919640 	miss:          0 	sync & hrtimer: percpu objpool from vmalloc
[   50.531382]     duration: 1055822us 	hits:    3407221 	miss:     830219 	sync overrun: percpu objpool
[   50.538135]     duration: 1055998us 	hits:    3404624 	miss:     854160 	sync overrun: percpu objpool from vmalloc
[   50.546686]     duration: 1046104us 	hits:   19464798 	miss:          0 	async: percpu objpool
[   50.552989]     duration: 1033054us 	hits:   18957836 	miss:          0 	async: percpu objpool from vmalloc
[   50.560289]     duration: 1041778us 	hits:   33806868 	miss:          0 	async & hrtimer: percpu objpool
[   50.567425]     duration: 1048901us 	hits:   34211860 	miss:          0 	async & hrtimer: percpu objpool from vmalloc

Simplified:
[   48.393236] Summary of testcases:
[   48.395384]     duration: 1013002us 	hits:   29661448 	miss:          0 	sync: percpu objpool
[   48.400351]     duration: 1057231us 	hits:   31035578 	miss:          0 	sync: percpu objpool from vmalloc
[   48.405660]     duration: 1043196us 	hits:   30546652 	miss:          0 	sync & hrtimer: percpu objpool
[   48.411216]     duration: 1047128us 	hits:   30601306 	miss:          0 	sync & hrtimer: percpu objpool from vmalloc
[   48.417231]     duration: 1051695us 	hits:    3468287 	miss:     892881 	sync overrun: percpu objpool
[   48.422405]     duration: 1054003us 	hits:    3549491 	miss:     898141 	sync overrun: percpu objpool from vmalloc
[   48.428425]     duration: 1052946us 	hits:   19005228 	miss:          0 	async: percpu objpool
[   48.433597]     duration: 1051757us 	hits:   19670866 	miss:          0 	async: percpu objpool from vmalloc
[   48.439280]     duration: 1042951us 	hits:   37135332 	miss:          0 	async & hrtimer: percpu objpool
[   48.445085]     duration: 1029803us 	hits:   37093248 	miss:          0 	async & hrtimer: percpu objpool from vmalloc

Can you test it too?

Thanks,