[RFC PATCH 0/3] nvme sq associations

Chaitanya Kulkarni chaitanyak at nvidia.com
Tue Sep 28 23:07:38 PDT 2021


On 9/24/21 2:08 PM, Andrey Nikitin wrote:
> The NVMe specification allows for namespaces with different performance
> characteristics, as well as allowing IOs submissions to any namespace via
> any non-empty submission queue. However, sharing queue resources between
> namespaces with different performance characteristics can cause undesired
> behavior (e.g. head-of-line-blocking for IOs that target a high-performance
> namespace behind IOs that target a low performance namespace via the same
> queue). In addition, the lack of hardware queue isolation support can cause
> “noisy neighbor” type problems for applications issuing IOs to different
> namespaces of the same controller. This problem may be especially pronounced
> in multi-tenant environments such as the ones provided by cloud services.
> 

For RFC such as this you need to provide a quantitative data for 
different usecases for targeted (e.g. noisy neighbor problem) and non
targeted workloads (e.g. standard fio perf) and also the performance 
impact of this change on the the hot path.




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