From: Boaz Harrosh <bharrosh@panasas.com>
To: Roland Dreier <roland@purestorage.com>
Subject: Re: [LSF/MM TOPIC] Copy offload
Date: Tue, 24 Jan 2012 12:16:48 +0200 [thread overview]
Message-ID: <4F1E8510.80003@panasas.com> (raw)
In-Reply-To: <CAL1RGDWJjzBnN6Aj_ngvkFco_toe8Dey5QApgmYafpEqECuTSw@mail.gmail.com>
On 01/13/2012 09:35 PM, Roland Dreier wrote:
> In general, with my target vendor hat on, I'd be very interested in
> what special SCSI commands the Linux initiator stack might want
> to use. Extended copy is one (very complex) case -- and BTW
> Microsoft seems to plan on using XCOPY LITE with NTFS.
>
> Another possibly interesting example would be COMPARE AND
> WRITE for clustered filesystems.
>
> Any other storage operations that FS developers might want
> from the block device? (Either standard SCSI commands or
> more speculative stuff that T10 hasn't thought of yet)
>
copy-and-modify
the command looks like a a write with destination [write_start, num_sectors]
The command also receives a read destination [read_start, num_sectors]
where read_start <= write_start && write_start+num_sectors <= read_start+num_sectors
That's for the like of pNFS blocks layout where the FS maintains a copy-on-write
with FS blocks larger than a sector. Today it needs to do the copy then the
modification. (2 + 1) operations instead of 1
Na, too marginal. Is it worth it? It might depend on the FS block size.
Just some crazy idea
Boaz
> - R.
> --
> To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
prev parent reply other threads:[~2012-01-24 10:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-09 10:27 [LSF/MM TOPIC] Copy offload Hannes Reinecke
2012-01-10 22:11 ` Joel Becker
2012-01-13 19:25 ` Martin K. Petersen
2012-01-13 19:25 ` Martin K. Petersen
2012-01-13 19:35 ` Roland Dreier
2012-01-24 10:16 ` Boaz Harrosh [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=4F1E8510.80003@panasas.com \
--to=bharrosh@panasas.com \
--cc=roland@purestorage.com \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.