Re: [SPDK] Does SPDK have specific requirement for NVMe SSDs(device controller) to get it working in the best way?

Re: [SPDK] Does SPDK have specific requirement for NVMe SSDs(device controller) to get it working in the best way?

[Walker, Benjamin]

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On Mon, 2019-03-25 at 18:07 +0000, Liang Yang wrote:
> For example, how many I/O queue pairs, MSI-X messages, MDTS etc.

Most NVMe devices only need 1 I/O queue pair to get their full performance, but
that's ultimately up to the device. SPDK places no new requirements above what
the device requires.

SPDK does not use interrupts, so MSI-X is all disabled and doesn't matter.

SPDK will just automatically do the right thing for MDTS and optimal write size
and striping and all of that. You don't have to worry about it.

Thanks,
Ben


> 
> Liang
> 
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> SPDK mailing list
> SPDK(a)lists.01.org
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Re: [SPDK] Does SPDK have specific requirement for NVMe SSDs(device controller) to get it working in the best way?

[Harris, James R]

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On 3/26/19, 9:45 AM, "SPDK on behalf of Liang Yang" <spdk-bounces(a)lists.01.org on behalf of liangy(a)microsoft.com> wrote:

>    I understand for SPDK every I/O queue pairs operate in poll mode. But since you said "SPDK does not use interrupts", do you mean even the admin queue pair works in polling mode too with interrupt disabled?

Hi Liang,

Yes - that is correct.

-Jim

    
    -----Original Message-----
    From: SPDK <spdk-bounces(a)lists.01.org> On Behalf Of Walker, Benjamin
    Sent: Monday, March 25, 2019 1:08 PM
    To: spdk(a)lists.01.org
    Subject: Re: [SPDK] Does SPDK have specific requirement for NVMe SSDs(device controller) to get it working in the best way?
    
    On Mon, 2019-03-25 at 18:07 +0000, Liang Yang wrote:
    > For example, how many I/O queue pairs, MSI-X messages, MDTS etc.
    
    Most NVMe devices only need 1 I/O queue pair to get their full performance, but that's ultimately up to the device. SPDK places no new requirements above what the device requires.
    
    SPDK does not use interrupts, so MSI-X is all disabled and doesn't matter.
    
    SPDK will just automatically do the right thing for MDTS and optimal write size and striping and all of that. You don't have to worry about it.
    
    Thanks,
    Ben
    
    
    > 
    > Liang
    > 
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Re: [SPDK] Does SPDK have specific requirement for NVMe SSDs(device controller) to get it working in the best way?

[Liang Yang]

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I understand for SPDK every I/O queue pairs operate in poll mode. But since you said "SPDK does not use interrupts", do you mean even the admin queue pair works in polling mode too with interrupt disabled?


-----Original Message-----
From: SPDK <spdk-bounces(a)lists.01.org> On Behalf Of Walker, Benjamin
Sent: Monday, March 25, 2019 1:08 PM
To: spdk(a)lists.01.org
Subject: Re: [SPDK] Does SPDK have specific requirement for NVMe SSDs(device controller) to get it working in the best way?

On Mon, 2019-03-25 at 18:07 +0000, Liang Yang wrote:
> For example, how many I/O queue pairs, MSI-X messages, MDTS etc.

Most NVMe devices only need 1 I/O queue pair to get their full performance, but that's ultimately up to the device. SPDK places no new requirements above what the device requires.

SPDK does not use interrupts, so MSI-X is all disabled and doesn't matter.

SPDK will just automatically do the right thing for MDTS and optimal write size and striping and all of that. You don't have to worry about it.

Thanks,
Ben


> 
> Liang
> 
> _______________________________________________
> SPDK mailing list
> SPDK(a)lists.01.org
> https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Flist
> s.01.org%2Fmailman%2Flistinfo%2Fspdk&amp;data=02%7C01%7Cliangy%40micro
> soft.com%7Cc6782acbee8e451260f808d6b15da6d5%7C72f988bf86f141af91ab2d7c
> d011db47%7C1%7C1%7C636891413137262799&amp;sdata=4Mu998%2Buia5WsYkageTS
> 0QEPwkz%2B4C%2F8nSbYTpOfJ3c%3D&amp;reserved=0

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[SPDK] Does SPDK have specific requirement for NVMe SSDs(device controller) to get it working in the best way?

[Liang Yang]

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For example, how many I/O queue pairs, MSI-X messages, MDTS etc.

Liang