From: Nathaniel W Filardo <nwf@cs.jhu.edu>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
Subject: Re: [9fans] 9p over high-latency
Date: Fri, 26 Sep 2008 21:17:18 -0400 [thread overview]
Message-ID: <20080927011718.GG4111@masters13.cs.jhu.edu> (raw)
In-Reply-To: <140e7ec30809180257y34722805y287fd9838bd76f35@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 1891 bytes --]
On Thu, Sep 18, 2008 at 05:57:21PM +0800, sqweek wrote:
> On Fri, Sep 12, 2008 at 7:47 PM, erik quanstrom <quanstro@quanstro.net> wrote:
> > as an aside: i don't think 9p itself limits plan 9 performance
> > over high-latency links. the limitations have more to do with
> > the number of outstanding messages, which is 1 in the mnt
> > driver.
>
> Hm, but what's the alternative here? Readahead seems somewhat
> attractive, if difficult (I worry about blocking reads and timing
> sensitive file systems). But there's one problem I can't resolve - how
> do you know what offset to Tread without consulting the previous
> Rread's count?
> Actually, I understand there has been discussion about grouping tags
> to allow for things like Twalk/Topen batching without waiting for
> Rwalk (which sounds like a great idea), maybe that would work here
> also...
> -sqweek
>
This seems an appropriate time -- well, appropriate thread, if a few days
lagged -- to bring up Dave's/my cache journaling scheme for review... I
presented this at IWP9 last year and recieved mostly positive feedback, as I
remember, but sadly have not had a chance to work on it since. (That said,
it remains on my todo list should nobody beat me to it.)
The protocol design is documented on my server at
https://wiki.ietfng.org/pub/Plan9/JournalCallbacks. Sadly, it remains the
case that I don't have an implementation to offer.
The basic idea is to shim a client-side cache and a server-side cache
controller in front of a filesystem, like fossil or exportfs, and have the
cache controller snoop on all connections to the server, informing caches
when the contents of their caches have become invalid. There are a few
known deficiencies ([in]coherency and authentication being the two big
ones), but I hope the idea remains sound.
Thoughts and criticisms welcome. :)
--nwf;
[-- Attachment #2: Type: application/pgp-signature, Size: 204 bytes --]
next prev parent reply other threads:[~2008-09-27 1:17 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-18 9:57 sqweek
2008-09-18 10:36 ` Christian Kellermann
2008-09-18 10:48 ` Uriel
2008-09-27 1:17 ` Nathaniel W Filardo [this message]
2008-09-18 11:51 erik quanstrom
2008-09-18 13:34 ` Eric Van Hensbergen
[not found] <0a44b94d5b9fa0b13dc1d9ae11472e5e@quanstro.net>
2008-09-18 13:34 ` sqweek
2008-09-18 13:49 ` Eric Van Hensbergen
2008-09-18 17:26 ` Francisco J Ballesteros
2008-09-18 20:05 ` Steve Simon
2008-09-18 20:38 ` Francisco J Ballesteros
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=20080927011718.GG4111@masters13.cs.jhu.edu \
--to=nwf@cs.jhu.edu \
--cc=9fans@9fans.net \
/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 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).