From: Walker, Benjamin <benjamin.walker at intel.com>
To: spdk@lists.01.org
Subject: Re: [SPDK] IOPS of NVMe is ~1K/s at 1 queue depth but over 100K/s at 2 queue depth
Date: Fri, 29 Dec 2017 20:42:55 +0000 [thread overview]
Message-ID: <1514580173.2658.126.camel@intel.com> (raw)
In-Reply-To: CAKkMQdxpYbj5fuALOLLuWUkvTc6HgfD1C65JzsfZX_VNPKRSsg@mail.gmail.com
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On Fri, 2017-12-29 at 23:48 +0800, Li Wang wrote:
> Dear all,
>
> I am running nvme/perf with master branch on a EC2 instance (Redhat, 8 CPU
> cores). I noticed that the IOPS is around 1K when the queue depth is 1. By
> simply increase the queue length to 2, the IOPS grows to over 60K. May I ask
> if this is normal?
Is this an EC2 dedicated server (i.e. physical hardware) or a virtual machine?
Is the NVMe device you're connected to backed by a local NVMe device, a remote
NVMe device, or an EBS volume? Amazon presents basically all storage as NVMe
devices these days, but the actual backing storage can perform differently
depending on the circumstances.
In all cases I'm aware of, the NVMe device presented is not the actual NVMe SSD.
It's either a virtual NVMe device emulated in software, or it's implemented on a
special card that Amazon puts in between the platform and the real SSD. SPDK
hasn't been tested thoroughly with Amazon's emulated NVMe devices, so there
could be some issues there. Most NVMe devices historically were not validated
against polled mode, ultra high performance drivers so when SPDK was first
released we found a number of firmware bugs in existing SSDs that were only
exposed because SPDK was so fast. We're seeing less and less of that now, but
you could be hitting something like that here.
next reply other threads:[~2017-12-29 20:42 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-29 20:42 Walker, Benjamin [this message]
-- strict thread matches above, loose matches on Subject: below --
2018-01-03 13:05 [SPDK] IOPS of NVMe is ~1K/s at 1 queue depth but over 100K/s at 2 queue depth Li Wang
2018-01-02 23:53 Luse, Paul E
2018-01-02 20:47 Brijesh Singh
2018-01-01 16:20 Luse, Paul E
2018-01-01 13:47 Li Wang
2017-12-31 4:56 Li Wang
2017-12-30 14:47 Brijesh Singh
2017-12-30 9:53 Li Wang
2017-12-30 4:06 Brijesh Singh
2017-12-30 3:39 Li Wang
2017-12-30 3:32 Crane Chu
2017-12-30 1:57 Li Wang
2017-12-29 15:48 Li Wang
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