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From: Sagi Grimberg <sagi@grimberg.me>
To: Chaitanya Kulkarni <chaitanyak@nvidia.com>,
	Andrey Nikitin <nikitina@amazon.com>,
	"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>
Cc: "benh@kernel.crashing.org" <benh@kernel.crashing.org>,
	"davebuch@amazon.com" <davebuch@amazon.com>
Subject: Re: [RFC PATCH 0/3] nvme sq associations
Date: Wed, 29 Sep 2021 16:17:20 +0300	[thread overview]
Message-ID: <bfdae9a1-2250-d75f-8dab-7137a3211984@grimberg.me> (raw)
In-Reply-To: <5f65579c-0eb4-cf23-4237-e23f52ccd63f@nvidia.com>


>> 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.

Agreed.

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  reply	other threads:[~2021-09-29 13:18 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-24 21:08 [RFC PATCH 0/3] nvme sq associations Andrey Nikitin
2021-09-24 21:08 ` [RFC PATCH 1/3] nvme: split admin queue in pci Andrey Nikitin
2021-09-24 21:08 ` [RFC PATCH 2/3] nvme: add NVM set structures Andrey Nikitin
2021-09-24 21:08 ` [RFC PATCH 3/3] nvme: implement SQ associations Andrey Nikitin
2021-09-25  3:02 ` [RFC PATCH 0/3] nvme sq associations Keith Busch
2021-09-25  8:31   ` Benjamin Herrenschmidt
2021-09-25  8:36     ` Christoph Hellwig
2021-09-29  6:07 ` Chaitanya Kulkarni
2021-09-29 13:17   ` Sagi Grimberg [this message]
2021-09-29  0:48 Nikitin, Andrey
2021-09-29  1:35 ` Keith Busch

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