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From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Suganath Prabu S <suganath-prabu.subramani@broadcom.com>
Cc: jejb@kernel.org, hch@infradead.org, martin.petersen@oracle.com,
	linux-scsi@vger.kernel.org, Sathya.Prakash@broadcom.com,
	kashyap.desai@broadcom.com, linux-kernel@vger.kernel.org,
	chaitra.basappa@broadcom.com, sreekanth.reddy@broadcom.com,
	linux-nvme@lists.infradead.org
Subject: Re: [PATCH v4 00/14] mpt3sas driver NVMe support:
Date: Tue, 22 Aug 2017 22:18:06 -0400	[thread overview]
Message-ID: <yq1lgmbauxt.fsf@oracle.com> (raw)
In-Reply-To: <1503322344-5900-1-git-send-email-suganath-prabu.subramani@broadcom.com> (Suganath Prabu S.'s message of "Mon, 21 Aug 2017 19:02:10 +0530")


Suganath,

>   mpt3sas: SGL to PRP Translation for I/Os to NVMe  devices

I'm still confused about this patch.

 - I don't understand why you go through all these hoops to decide
   whether to use PRPs or IEEE scatterlists. If the firmware translation
   is slow, why even bother with the SG format in the first place? Set
   the max I/O size to match MDTS and you're done.

 - What's the benefit of using SG for regular I/O commands?

 - If the unmap translation in firmware is slow, why don't you translate
   WRITE SAME/w UNMAP set to DSM DEALLOCATE without requiring
   applications to do encapsulated passthrough?

Also make sure you attribute your patches correctly (From: root
<root@dhcp-135-24-192-103.dhcp.avagotech.net>). And you don't need that
long CC: list. Just send the patch series to linux-scsi@vger.kernel.org.

Thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering

WARNING: multiple messages have this Message-ID (diff)
From: martin.petersen@oracle.com (Martin K. Petersen)
Subject: [PATCH v4 00/14] mpt3sas driver NVMe support:
Date: Tue, 22 Aug 2017 22:18:06 -0400	[thread overview]
Message-ID: <yq1lgmbauxt.fsf@oracle.com> (raw)
In-Reply-To: <1503322344-5900-1-git-send-email-suganath-prabu.subramani@broadcom.com> (Suganath Prabu S.'s message of "Mon, 21 Aug 2017 19:02:10 +0530")


Suganath,

>   mpt3sas: SGL to PRP Translation for I/Os to NVMe  devices

I'm still confused about this patch.

 - I don't understand why you go through all these hoops to decide
   whether to use PRPs or IEEE scatterlists. If the firmware translation
   is slow, why even bother with the SG format in the first place? Set
   the max I/O size to match MDTS and you're done.

 - What's the benefit of using SG for regular I/O commands?

 - If the unmap translation in firmware is slow, why don't you translate
   WRITE SAME/w UNMAP set to DSM DEALLOCATE without requiring
   applications to do encapsulated passthrough?

Also make sure you attribute your patches correctly (From: root
<root at dhcp-135-24-192-103.dhcp.avagotech.net>). And you don't need that
long CC: list. Just send the patch series to linux-scsi at vger.kernel.org.

Thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering

  parent reply	other threads:[~2017-08-23  2:19 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-21 13:32 [PATCH v4 00/14] mpt3sas driver NVMe support: Suganath Prabu S
2017-08-21 13:32 ` Suganath Prabu S
2017-08-21 13:32 ` [PATCH v4 01/14] mpt3sas: Update MPI Header Suganath Prabu S
2017-08-21 13:32   ` Suganath Prabu S
2017-08-21 13:32 ` [PATCH v4 02/14] mpt3sas: Add nvme device support in slave alloc, target alloc and probe Suganath Prabu S
2017-08-21 13:32   ` Suganath Prabu S
2017-08-21 13:32 ` [PATCH v4 03/14] mpt3sas: SGL to PRP Translation for I/Os to NVMe devices Suganath Prabu S
2017-08-21 13:32   ` Suganath Prabu S
2017-08-21 13:32 ` [PATCH v4 04/14] mpt3sas: Added support for nvme encapsulated request message Suganath Prabu S
2017-08-21 13:32   ` Suganath Prabu S
2017-08-21 13:32 ` [PATCH v4 05/14] mpt3sas: API 's to support NVMe drive addition to SML Suganath Prabu S
2017-08-21 13:32   ` Suganath Prabu S
2017-08-21 13:32 ` [PATCH v4 06/14] mpt3sas: API's to remove nvme drive from sml Suganath Prabu S
2017-08-21 13:32   ` Suganath Prabu S
2017-08-21 13:32 ` [PATCH v4 07/14] mpt3sas: Handle NVMe PCIe device related events generated from firmware Suganath Prabu S
2017-08-21 13:32   ` Suganath Prabu S
2017-08-21 13:32 ` [PATCH v4 08/14] mpt3sas: Set NVMe device queue depth as 128 Suganath Prabu S
2017-08-21 13:32   ` Suganath Prabu S
2017-08-21 13:32 ` [PATCH v4 09/14] mpt3sas: scan and add nvme device after controller reset Suganath Prabu S
2017-08-21 13:32   ` Suganath Prabu S
2017-08-21 13:32 ` [PATCH v4 10/14] mpt3as: Add-Task-management-debug-info-for-NVMe-drives Suganath Prabu S
2017-08-21 13:32   ` Suganath Prabu S
2017-08-21 13:32 ` [PATCH v4 11/14] mpt3sas: NVMe drive support for BTDHMAPPING ioctl command and log info Suganath Prabu S
2017-08-21 13:32   ` Suganath Prabu S
2017-08-21 13:32 ` [PATCH v4 12/14] mpt3sas: Fix nvme drives checking for tlr Suganath Prabu S
2017-08-21 13:32   ` Suganath Prabu S
2017-08-21 13:32 ` [PATCH v4 13/14] mpt3sas: Update mpt3sas driver version Suganath Prabu S
2017-08-21 13:32   ` Suganath Prabu S
2017-08-21 13:32 ` [PATCH v4 14/14] mpt3sas: Fix sparse warning Suganath Prabu S
2017-08-21 13:32   ` Suganath Prabu S
2017-08-23  2:18 ` Martin K. Petersen [this message]
2017-08-23  2:18   ` [PATCH v4 00/14] mpt3sas driver NVMe support: Martin K. Petersen
2017-08-30 12:30   ` Suganath Prabu Subramani
2017-08-30 12:30     ` Suganath Prabu Subramani
2017-08-31  3:05     ` Martin K. Petersen
2017-08-31  3:05       ` Martin K. Petersen
2017-08-31  4:58       ` Suganath Prabu Subramani
2017-08-31  4:58         ` Suganath Prabu Subramani
2017-09-01  3:22         ` Martin K. Petersen
2017-09-01  3:22           ` Martin K. Petersen
2017-09-01  8:39           ` Suganath Prabu Subramani
2017-09-01  8:39             ` Suganath Prabu Subramani
2017-09-13  7:15             ` Suganath Prabu Subramani
2017-09-13  7:15               ` Suganath Prabu Subramani
2017-09-15  1:07               ` Martin K. Petersen
2017-09-15  1:07                 ` Martin K. Petersen
2017-09-18 10:39                 ` Suganath Prabu Subramani
2017-09-18 10:39                   ` Suganath Prabu Subramani
2017-09-25 20:22                   ` Martin K. Petersen
2017-09-25 20:22                     ` Martin K. Petersen

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