From: Nikos Tsironis <ntsironis@arrikto.com>
To: Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
"dm-devel@redhat.com" <dm-devel@redhat.com>,
"lsf-pc@lists.linux-foundation.org"
<lsf-pc@lists.linux-foundation.org>
Cc: "axboe@kernel.dk" <axboe@kernel.dk>,
"msnitzer@redhat.com" <msnitzer@redhat.com>,
"bvanassche@acm.org" <bvanassche@acm.org>,
"martin.petersen@oracle.com" <martin.petersen@oracle.com>,
"roland@purestorage.com" <roland@purestorage.com>,
"mpatocka@redhat.com" <mpatocka@redhat.com>,
"hare@suse.de" <hare@suse.de>,
"kbusch@kernel.org" <kbusch@kernel.org>,
"rwheeler@redhat.com" <rwheeler@redhat.com>,
"hch@lst.de" <hch@lst.de>,
"Frederick.Knight@netapp.com" <Frederick.Knight@netapp.com>,
"zach.brown@ni.com" <zach.brown@ni.com>,
"osandov@fb.com" <osandov@fb.com>
Subject: Re: [LSF/MM/BFP ATTEND] [LSF/MM/BFP TOPIC] Storage: Copy Offload
Date: Fri, 11 Jun 2021 18:35:30 +0300 [thread overview]
Message-ID: <9b14e6c3-8880-4694-1b7e-c82cacd8c9c0@arrikto.com> (raw)
In-Reply-To: <BYAPR04MB49652C4B75E38F3716F3C06386539@BYAPR04MB4965.namprd04.prod.outlook.com>
On 5/11/21 3:15 AM, Chaitanya Kulkarni wrote:
> Hi,
>
> * Background :-
> -----------------------------------------------------------------------
>
> Copy offload is a feature that allows file-systems or storage devices
> to be instructed to copy files/logical blocks without requiring
> involvement of the local CPU.
>
> With reference to the RISC-V summit keynote [1] single threaded
> performance is limiting due to Denard scaling and multi-threaded
> performance is slowing down due Moore's law limitations. With the rise
> of SNIA Computation Technical Storage Working Group (TWG) [2],
> offloading computations to the device or over the fabrics is becoming
> popular as there are several solutions available [2]. One of the common
> operation which is popular in the kernel and is not merged yet is Copy
> offload over the fabrics or on to the device.
>
> * Problem :-
> -----------------------------------------------------------------------
>
> The original work which is done by Martin is present here [3]. The
> latest work which is posted by Mikulas [4] is not merged yet. These two
> approaches are totally different from each other. Several storage
> vendors discourage mixing copy offload requests with regular READ/WRITE
> I/O. Also, the fact that the operation fails if a copy request ever
> needs to be split as it traverses the stack it has the unfortunate
> side-effect of preventing copy offload from working in pretty much
> every common deployment configuration out there.
>
> * Current state of the work :-
> -----------------------------------------------------------------------
>
> With [3] being hard to handle arbitrary DM/MD stacking without
> splitting the command in two, one for copying IN and one for copying
> OUT. Which is then demonstrated by the [4] why [3] it is not a suitable
> candidate. Also, with [4] there is an unresolved problem with the
> two-command approach about how to handle changes to the DM layout
> between an IN and OUT operations.
>
> * Why Linux Kernel Storage System needs Copy Offload support now ?
> -----------------------------------------------------------------------
>
> With the rise of the SNIA Computational Storage TWG and solutions [2],
> existing SCSI XCopy support in the protocol, recent advancement in the
> Linux Kernel File System for Zoned devices (Zonefs [5]), Peer to Peer
> DMA support in the Linux Kernel mainly for NVMe devices [7] and
> eventually NVMe Devices and subsystem (NVMe PCIe/NVMeOF) will benefit
> from Copy offload operation.
>
> With this background we have significant number of use-cases which are
> strong candidates waiting for outstanding Linux Kernel Block Layer Copy
> Offload support, so that Linux Kernel Storage subsystem can to address
> previously mentioned problems [1] and allow efficient offloading of the
> data related operations. (Such as move/copy etc.)
>
> For reference following is the list of the use-cases/candidates waiting
> for Copy Offload support :-
>
> 1. SCSI-attached storage arrays.
> 2. Stacking drivers supporting XCopy DM/MD.
> 3. Computational Storage solutions.
> 7. File systems :- Local, NFS and Zonefs.
> 4. Block devices :- Distributed, local, and Zoned devices.
> 5. Peer to Peer DMA support solutions.
> 6. Potentially NVMe subsystem both NVMe PCIe and NVMeOF.
>
> * What we will discuss in the proposed session ?
> -----------------------------------------------------------------------
>
> I'd like to propose a session to go over this topic to understand :-
>
> 1. What are the blockers for Copy Offload implementation ?
> 2. Discussion about having a file system interface.
> 3. Discussion about having right system call for user-space.
> 4. What is the right way to move this work forward ?
> 5. How can we help to contribute and move this work forward ?
>
> * Required Participants :-
> -----------------------------------------------------------------------
>
> I'd like to invite file system, block layer, and device drivers
> developers to:-
>
> 1. Share their opinion on the topic.
> 2. Share their experience and any other issues with [4].
> 3. Uncover additional details that are missing from this proposal.
>
> Required attendees :-
>
> Martin K. Petersen
> Jens Axboe
> Christoph Hellwig
> Bart Van Assche
> Zach Brown
> Roland Dreier
> Ric Wheeler
> Trond Myklebust
> Mike Snitzer
> Keith Busch
> Sagi Grimberg
> Hannes Reinecke
> Frederick Knight
> Mikulas Patocka
> Keith Busch
>
> Regards,
> Chaitanya
>
> [1]https://content.riscv.org/wp-content/uploads/2018/12/A-New-Golden-Age-for-Computer-Architecture-History-Challenges-and-Opportunities-David-Patterson-.pdf
> [2] https://www.snia.org/computational
> https://www.napatech.com/support/resources/solution-descriptions/napatech-smartnic-solution-for-hardware-offload/
> https://www.eideticom.com/products.html
> https://www.xilinx.com/applications/data-center/computational-storage.html
> [3] git://git.kernel.org/pub/scm/linux/kernel/git/mkp/linux.git xcopy
> [4] https://www.spinics.net/lists/linux-block/msg00599.html
> [5] https://lwn.net/Articles/793585/
> [6] https://nvmexpress.org/new-nvmetm-specification-defines-zoned-
> namespaces-zns-as-go-to-industry-technology/
> [7] https://github.com/sbates130272/linux-p2pmem
> [8] https://kernel.dk/io_uring.pdf
>
I would like to participate in this discussion too.
Thanks,
Nikos
next prev parent reply other threads:[~2021-06-11 15:35 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-11 0:15 [LSF/MM/BFP ATTEND] [LSF/MM/BFP TOPIC] Storage: Copy Offload Chaitanya Kulkarni
2021-05-11 21:15 ` Knight, Frederick
2021-05-12 2:21 ` Bart Van Assche
[not found] ` <CGME20210512071321eucas1p2ca2253e90449108b9f3e4689bf8e0512@eucas1p2.samsung.com>
2021-05-12 7:13 ` Javier González
2021-05-12 7:30 ` Johannes Thumshirn
[not found] ` <CGME20210928191342eucas1p23448dcd51b23495fa67cdc017e77435c@eucas1p2.samsung.com>
2021-09-28 19:13 ` Javier González
2021-09-29 6:44 ` Johannes Thumshirn
2021-09-30 9:43 ` Chaitanya Kulkarni
2021-09-30 9:53 ` Javier González
2021-10-06 10:01 ` Javier González
2021-10-13 8:35 ` Javier González
2021-09-30 16:20 ` Bart Van Assche
2021-10-06 10:05 ` Javier González
2021-10-06 17:33 ` Bart Van Assche
2021-10-08 6:49 ` Javier González
2021-10-29 0:21 ` Chaitanya Kulkarni
2021-10-29 5:51 ` Hannes Reinecke
2021-10-29 8:16 ` Javier González
2021-10-29 16:15 ` Bart Van Assche
2021-11-01 17:54 ` Keith Busch
2021-10-29 8:14 ` Javier González
2021-11-03 19:27 ` Javier González
2021-11-16 13:43 ` Javier González
2021-11-16 17:59 ` Bart Van Assche
2021-11-17 12:53 ` Javier González
2021-11-17 15:52 ` Bart Van Assche
2021-11-19 7:38 ` Javier González
2021-11-19 10:47 ` Kanchan Joshi
2021-11-19 15:51 ` Keith Busch
2021-11-19 16:21 ` Bart Van Assche
2021-11-22 7:39 ` Kanchan Joshi
2021-05-12 15:23 ` Hannes Reinecke
2021-05-12 15:45 ` Himanshu Madhani
2021-05-17 16:39 ` Kanchan Joshi
2021-05-18 0:15 ` Bart Van Assche
2021-06-11 6:03 ` Chaitanya Kulkarni
2021-06-11 15:35 ` Nikos Tsironis [this message]
[not found] <CGME20230113094723epcas5p2f6f81ca1ad85f4b26829b87f8ec301ce@epcas5p2.samsung.com>
2023-01-13 9:46 ` Nitesh Shetty
[not found] <CGME20220127071544uscas1p2f70f4d2509f3ebd574b7ed746d3fa551@uscas1p2.samsung.com>
2022-01-27 7:14 ` Chaitanya Kulkarni
2022-01-28 19:59 ` Adam Manzanares
2022-01-31 11:49 ` Johannes Thumshirn
2022-01-31 19:03 ` Bart Van Assche
2022-02-01 1:54 ` Luis Chamberlain
2022-02-01 10:21 ` Javier González
2022-02-07 9:57 ` Nitesh Shetty
2022-02-02 5:57 ` Kanchan Joshi
2022-02-07 10:45 ` David Disseldorp
2022-03-01 17:34 ` Nikos Tsironis
2022-03-01 21:32 ` Chaitanya Kulkarni
2022-03-03 18:36 ` Nikos Tsironis
2022-03-08 20:48 ` Nikos Tsironis
2022-03-09 8:51 ` Mikulas Patocka
2022-03-09 15:49 ` Nikos Tsironis
[not found] <CGME20200107181551epcas5p4f47eeafd807c28a26b4024245c4e00ab@epcas5p4.samsung.com>
2020-01-07 18:14 ` Chaitanya Kulkarni
2020-01-08 10:17 ` Javier González
2020-01-09 0:51 ` Logan Gunthorpe
2020-01-09 3:18 ` Bart Van Assche
2020-01-09 4:01 ` Chaitanya Kulkarni
2020-01-09 5:56 ` Damien Le Moal
2020-01-10 5:33 ` Martin K. Petersen
2020-01-24 14:23 ` Nikos Tsironis
2020-02-13 5:11 ` joshi.k
2020-02-13 13:09 ` Knight, Frederick
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