Re: [PATCH v2 0/8] io-pgtable lock removal

Leizhen (ThunderTown)
2017-06-26T13:19:40Z

On 2017/6/26 21:12, John Garry wrote:
>
>>>
>>> I saw Will has already sent the pull request. But, FWIW, we are seeing
>>> roughly the same performance as v1 patchset. For PCI NIC, Zhou again
>>> found performance drop goes from ~15->8% with SMMU enabled, and for
>>> integrated storage controller [platform device], we still see a drop of
>>> about 50%, depending on datarates (Leizhen has been working on fixing
>>> this).
>>
>> Thanks for confirming. Following Joerg's suggestion that the storage
>> workloads may still depend on rbtree performance - it had slipped my
>> mind that even with small block sizes those could well be grouped into
>> scatterlists large enough to trigger a >64-page IOVA allocation - I've
>> taken the liberty of cooking up a simplified version of Leizhen's rbtree
>> optimisation series in the iommu/iova branch of my tree. I'll follow up
>> on that after the merge window, but if anyone wants to play with it in
>> the meantime feel free.
The main problem is lock confliction of cmd queue. I have prepared my patchset,
I will send it later.

>
> Just a reminder that we did also see poor performance with our integrated NIC on your v1 patchset also (I can push for v2 patchset testing, but expect the same).
>
> We might be able to now include a LSI 3108 PCI SAS card in our testing also to give a broader set of results.
>
> John
>
>>
>> Robin.
>>
>> .
>>
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> .
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--
Thanks!
BestRegards