From: Tokunori Ikegami <ikegami.t@gmail.com>
To: Keith Busch <kbusch@kernel.org>
Cc: Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>
Subject: Re: [PATCH] block, nvme: Increase max segments parameter setting value
Date: Wed, 25 Mar 2020 01:51:23 +0900 [thread overview]
Message-ID: <6b73db44-ca3f-4285-0c91-dc1b1a5ca9f1@gmail.com> (raw)
In-Reply-To: <20200324000237.GB15091@redsun51.ssa.fujisawa.hgst.com>
On 2020/03/24 9:02, Keith Busch wrote:
> On Tue, Mar 24, 2020 at 08:09:19AM +0900, Tokunori Ikegami wrote:
>> Hi,
>>> The change looks okay, but why do we need such a large data length ?
>>>
>>> Do you have a use-case or performance numbers ?
>> We use the large data length to get log page by the NVMe admin command.
>> In the past it was able to get with the same length but failed currently
>> with it.
>>
>> So it seems that depended on the kernel version as caused by the version up.
> We didn't have 32-bit max segments before, though. Why was 16-bits
> enough in older kernels? Which kernel did this stop working?
Now I am asking the detail information to the reporter so let me update
later.
That was able to use the same command script with the large data length
in the past.
>
>> Also I have confirmed that currently failed with the length 0x10000000
>> 256MB.
> If your hitting max segment limits before any other limit, you should be
> able to do larger transfers with more physically contiguous memory. Huge
> pages can get the same data length in fewer segments, if you want to
> try that.
>
> But wouldn't it be better if your application splits the transfer into
> smaller chunks across multiple commands? NVMe log page command supports
> offsets for this reason.
Yes actually now we are using the offset parameter to split the data to get.
For a future usage it seems that it is better to use the large number
size also.
WARNING: multiple messages have this Message-ID (diff)
From: Tokunori Ikegami <ikegami.t@gmail.com>
To: Keith Busch <kbusch@kernel.org>
Cc: "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>
Subject: Re: [PATCH] block, nvme: Increase max segments parameter setting value
Date: Wed, 25 Mar 2020 01:51:23 +0900 [thread overview]
Message-ID: <6b73db44-ca3f-4285-0c91-dc1b1a5ca9f1@gmail.com> (raw)
In-Reply-To: <20200324000237.GB15091@redsun51.ssa.fujisawa.hgst.com>
On 2020/03/24 9:02, Keith Busch wrote:
> On Tue, Mar 24, 2020 at 08:09:19AM +0900, Tokunori Ikegami wrote:
>> Hi,
>>> The change looks okay, but why do we need such a large data length ?
>>>
>>> Do you have a use-case or performance numbers ?
>> We use the large data length to get log page by the NVMe admin command.
>> In the past it was able to get with the same length but failed currently
>> with it.
>>
>> So it seems that depended on the kernel version as caused by the version up.
> We didn't have 32-bit max segments before, though. Why was 16-bits
> enough in older kernels? Which kernel did this stop working?
Now I am asking the detail information to the reporter so let me update
later.
That was able to use the same command script with the large data length
in the past.
>
>> Also I have confirmed that currently failed with the length 0x10000000
>> 256MB.
> If your hitting max segment limits before any other limit, you should be
> able to do larger transfers with more physically contiguous memory. Huge
> pages can get the same data length in fewer segments, if you want to
> try that.
>
> But wouldn't it be better if your application splits the transfer into
> smaller chunks across multiple commands? NVMe log page command supports
> offsets for this reason.
Yes actually now we are using the offset parameter to split the data to get.
For a future usage it seems that it is better to use the large number
size also.
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linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme
next prev parent reply other threads:[~2020-03-24 16:51 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-23 18:23 [PATCH] block, nvme: Increase max segments parameter setting value Tokunori Ikegami
2020-03-23 18:23 ` Tokunori Ikegami
2020-03-23 19:14 ` Chaitanya Kulkarni
2020-03-23 19:14 ` Chaitanya Kulkarni
2020-03-23 23:09 ` Tokunori Ikegami
2020-03-23 23:09 ` Tokunori Ikegami
2020-03-24 0:02 ` Keith Busch
2020-03-24 0:02 ` Keith Busch
2020-03-24 16:51 ` Tokunori Ikegami [this message]
2020-03-24 16:51 ` Tokunori Ikegami
2020-03-27 17:50 ` Tokunori Ikegami
2020-03-27 17:50 ` Tokunori Ikegami
2020-03-27 18:18 ` Keith Busch
2020-03-27 18:18 ` Keith Busch
2020-03-28 2:11 ` Ming Lei
2020-03-28 2:11 ` Ming Lei
2020-03-28 3:13 ` Keith Busch
2020-03-28 3:13 ` Keith Busch
2020-03-28 8:28 ` Ming Lei
2020-03-28 8:28 ` Ming Lei
2020-03-28 12:57 ` Tokunori Ikegami
2020-03-28 12:57 ` Tokunori Ikegami
2020-03-29 3:01 ` Ming Lei
2020-03-29 3:01 ` Ming Lei
2020-03-30 9:15 ` Tokunori Ikegami
2020-03-30 9:15 ` Tokunori Ikegami
2020-03-30 13:53 ` Keith Busch
2020-03-30 13:53 ` Keith Busch
2020-03-31 15:24 ` Tokunori Ikegami
2020-03-31 15:24 ` Tokunori Ikegami
2020-03-31 14:13 ` Joshi
2020-03-31 14:13 ` Joshi
2020-03-31 15:37 ` Tokunori Ikegami
2020-03-31 15:37 ` Tokunori Ikegami
2020-03-24 7:16 ` Hannes Reinecke
2020-03-24 7:16 ` Hannes Reinecke
2020-03-24 17:17 ` Tokunori Ikegami
2020-03-24 17:17 ` Tokunori Ikegami
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