From: Selva Jove <firstname.lastname@example.org> To: James Bottomley <James.Bottomley@hansenpartnership.com> Cc: Bart Van Assche <email@example.com>, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org Subject: Re: [TECH TOPIC] Settling Copy Offload via NVMe SCC Date: Tue, 29 Jun 2021 20:10:41 +0530 [thread overview] Message-ID: <CAHqX9vaCHXKi9fnE7pbTNpavo511QwuZ=6j68xC_Jr9csn3LWw@mail.gmail.com> (raw) In-Reply-To: <de903dcd41f8881a103a8ca955347b0ef4f176f3.camel@HansenPartnership.com> Hi Bart and James, Thanks for the heads up. LSF/MM is a fine idea for the topic. It's just that we had a bit of uncertainty about in-person event and December felt somewhat distant. So we thought of making some progress by posting this to LPC. Thanks, Selva & Nitesh On Fri, Jun 25, 2021 at 9:38 PM James Bottomley <James.Bottomley@hansenpartnership.com> wrote: > > On Fri, 2021-06-25 at 09:02 -0700, Bart Van Assche wrote: > > On 6/25/21 7:47 AM, Selva Jove wrote: > > > The de-facto way of copying data in I/O stack has been pulling it > > > from one location followed by pushing to another. The farther the > > > application, requiring copy, is from storage, the longer it takes > > > for the trip to be over. With copy-offload the trips get shorter as > > > the storage device presents an interface to do internal data- > > > copying. This enables the host to optimise the pull-and-push > > > method, freeing up the host CPU, RAM and the fabric elements. > > > > > > The copy-offload interface has existed in SCSI storage for at least > > > a decade through XCOPY but faced insurmountable challenges in > > > getting into the Linux I/O stack. As for NVMe storage, copy-offload > > > made its way into the main specification with a new Simple Copy > > > Command(SCC) recently. This has stimulated a renewed interest and > > > efforts towards copy-offload in the Linux community. > > > > > > In this talk, we speak of the upstream efforts that we are doing > > > around SCC - > > > https://email@example.com/#r > > > > > > We'd extensively cover the design-decisions and seek the feedback > > > on the plumbing aspects such as - > > > > > > 1. User-interface. Should it be a new ioctl/syscall, io_uring based > > > opcode or must it fit into existing syscalls such as > > > copy_file_range. > > > 2. The transport mode between block-layer and NVMe. A chain of > > > empty bios (like discard) vs bio with payload. > > > 3. Must SCSI XCOPY compatibility be considered while we go about > > > building interfaces around NVMe SCC? > > > 4. Feasibility and challenges for in-kernel use cases, including > > > the file-systems and device-mappers > > > > This topic seems closely related to "Storage: Copy Offload" > > ( > > https://lore.kernel.org/linux-block/BYAPR04MB49652C4B75E38F3716F3C06386539@BYAPR04MB4965.namprd04.prod.outlook.com/ > > ). > > Not only that but it would seem to be better suited for LSF/MM on the > IO track than the kernel summit track of Plumbers: > > https://firstname.lastname@example.org/ > > Since the plumbing aspects are more how would current practitioners use > the API and how might we plumb it into filesystems. > > James > > > > Notes about implementing copy offloading are available at > > https://github.com/bvanassche/linux-kernel-copy-offload. > > > > Thanks, > > > > Bart. > > > >
prev parent reply other threads:[~2021-06-29 14:40 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-06-25 14:47 Selva Jove 2021-06-25 16:02 ` Bart Van Assche 2021-06-25 16:08 ` James Bottomley 2021-06-29 14:40 ` Selva Jove [this message]
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to='CAHqX9vaCHXKi9fnE7pbTNpavo511QwuZ=6j68xC_Jr9csn3LWw@mail.gmail.com' \ --email@example.com \ --cc=James.Bottomley@hansenpartnership.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --subject='Re: [TECH TOPIC] Settling Copy Offload via NVMe SCC' \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).