9fans - fans of the OS Plan 9 from Bell Labs
 help / color / mirror / Atom feed
From: erik quanstrom <quanstro@labs.coraid.com>
To: 9fans@9fans.net
Subject: Re: [9fans] Help with two small shared file servers
Date: Thu, 18 Aug 2011 09:26:28 -0400	[thread overview]
Message-ID: <ca21692ee3c00479507e73c08d172137@coraid.com> (raw)
In-Reply-To: <CAL4LZygoKQZoTvof4F_fBQhxqsQZb2r+FR_nkgf=YbU94WvoBQ@mail.gmail.c>

> > did you do testing at regular lan latencies?  what i see on my networks
> > is usually <= 30µs.
> >
> > - erik
> >
>
> I induced latencies similar to those found on the Internet. My tests at LAN
> speeds (500us in my sub-optimal setup) had 9P at essentially the same
> transfer rate as HTTP. My work was motivated by the observation that
> transferring files to and from sources is just deathly slow, and that while
> fcp does a good job helping that, it is just a patch covering a deeper
> issue.

i think fcp gets right at the heart of the matter.  issuing multiple outstanding
messages is how protocols like aoe, pcie, etc. get speed.  writes are posted.

the question for me is how does one make this easy and natural.  one way
is to allow the mnt driver to issue multiple concurrent reads or writes for
the same i/o.  another would be to use a system call ring to allow programs
to have an arbitrary number of outstanding system calls.

- erik



  parent reply	other threads:[~2011-08-18 13:26 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-08-17 10:09 Aram Hăvărneanu
2011-08-17 14:11 ` Anthony Sorace
2011-08-17 14:32   ` John Floren
2011-08-17 15:39   ` erik quanstrom
     [not found]   ` <CAL4LZyiEk35Kfq_wezUaEvJWsYX3ONeordrD7sQjFr+45fQiWg@mail.gmail.c>
2011-08-18  5:34     ` erik quanstrom
2011-08-18  5:48       ` John Floren
     [not found]       ` <CAL4LZygoKQZoTvof4F_fBQhxqsQZb2r+FR_nkgf=YbU94WvoBQ@mail.gmail.c>
2011-08-18 13:26         ` erik quanstrom [this message]
2011-08-18 14:21           ` Lucio De Re
2011-08-19  8:15           ` cinap_lenrek
2011-08-17 21:00 ` Bakul Shah
2011-08-17 21:19   ` John Floren
2011-08-17 21:22   ` Skip Tavakkolian
2011-08-18  5:29   ` erik quanstrom
2011-08-18  5:47     ` Tristan Plumb
2011-08-18  6:25     ` Bakul Shah
2011-08-30 21:40 ` Ethan Grammatikidis
     [not found] <CAEAzY3_Vx8WW1Oumt0t1_Ay6LtpTFFonpwMD+=0DYCM-yxXaeA@mail.gmail.c>
2011-08-17 15:42 ` erik quanstrom

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=ca21692ee3c00479507e73c08d172137@coraid.com \
    --to=quanstro@labs.coraid.com \
    --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).