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

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
> _______________________________________________
> SPDK mailing list -- spdk(a)lists.01.org
> To unsubscribe send an email to spdk-leave(a)lists.01.org
>