[SPDK] Re: Single iSCSI max performance with SPDK NULL Block Device

Hi,  Andrey

Thanks for quick reply. I will try 20.10.
Sorry for providing wrong information. Single target with SPDK NULL BDev
under 40G nic card, I got
100%RandWrite 4K : 135K
100%RandRead 4K : 155K

Although 135K for 1 SSD random write is enough, but not enough for read.
And if I compose 4 SSD into 1 raid-0 BDev, 135K is not enough.

Anyway, I will try 20.10 first. Thanks again

On Wed, Dec 9, 2020 at 8:36 PM Andrey Kuzmin <andrey.v.kuzmin(a)gmail.com>
wrote:

> On Wed, Dec 9, 2020, 15:14 Lego Lin <lego.lin(a)gmail.com> wrote:
>
> > Hi,
> >
> > Currently, I am using SPDK 19.04 evaluating SPDK iSCSI Performance. As
>
> I know, current SPDK iSCSI only uses 1 reactor to handle 1 target's iSCSI
> > IO.
> > When I try with SPDK NULL Block Device, the max performance with
> > 100%RandWrite / 40G NIC / BS = 4K is about 155K.
> >
>
> At 155K random write IOPS, the bottleneck can easily be in the actual SSD
> being used. Have you tested w/o SPDK iSCSI target being involved, with the
> same SSD in the direct attachment settings?
>
> Also, 19.04 is 1.5 years old, so you might want to upgrade to 20.10.
>
> Regards,
> Andrey
>
> I try to finish IO immediately at different layer : SPDK BDev Layer, SCSI
> > Layer.
> > It looks like iSCSI protocol handling become the bottleneck of SPDK NULL
> > Block Device.
> > Is there any way in SPDK to let multiple reactors handle 1 iSCSI target
> > IOs?
> >
> > Current test topology as following:
>
>
> > Client: FIO <--> /dev/sdb (Test 1: with 1 thread + with/without blk-mq,
> > Test 2: with 4 threads  + with/without blk-mq)
> > Target: 1 SPDK iSCSI target <--> 1 LUN <--> SPDK NULL Block Device
>
>
> > Thanks
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