[Pharo-dev] Spotter shortcut reset

Nicolas Cellier nicolas.cellier.aka.nice at gmail.com
Sun Feb 3 11:19:43 EST 2019


Ben,
The figures in the table are quite linear.
Duration * rate = constant.

It's just that you want to plot 1/ duration or 1/ rate if you don't want to
see an hyperbole x×y=cte

Le dim. 3 févr. 2019 à 12:17, ducasse <stepharo at netcourrier.com> a écrit :

> Wouahhhhhh you are not playing :)
> This is cool.
> My network at home is lame to the dispear of my sons.
>
> Stef
>
>
> On 3 Feb 2019, at 12:06, Ben Coman <btc at openinworld.com> wrote:
>
>
> On Sat, 2 Feb 2019 at 18:54, ducasse <stepharo at netcourrier.com> wrote:
> > On Sat, 2 Feb 2019 at 11:01, Ben Coman <btc at openinworld.com> wrote:
> >
> > > I am getting network errors trying to download latest Pharo Launcher,
> >
> > can you tell me how so that I try to reproduce it?
>
> Since network performance depends a lot on location, and presuming you'd
> need to be at my house to reproduce my experience,
> I spent the afternoon learning about AWS so I could do some testing from a
> Australian based cloud box
> that you should be able to reproduce fairly easily, since this was my
> first time using AWS.
>
> With this 10 minute tutorial...
> [Launch a Linux Virtual Machine](
> https://aws.amazon.com/getting-started/tutorials/launch-a-virtual-machine/
> )
> 1. Signed up and signed in
> Tip: I struggled a long while looping on "Sign in with root account
> credentials" until I discovered I needed to use the email address I signed
> up with, not the account name.
>
> [Edit:] In the top right between account name and support,
> pulled down list and selected "Asia Pacfic (Sydney)"
>
>
> 2. Clicked "Launch a virtual machine"
> (note, that only seems to show up for blank account, otherwise its "Launch
> Instance"
>
>
> 3. Ticked "Free tier only" filter.
> + Selected "Amazon Linux 2 AMI (HVM), SSD Volume Type"
> + Clicked <Review and Launch>  (used default t2.micro)
> + Clicked <Launch>
> + From the pull-down selected "Create a new key pair",
> gave it a name and clicked <Download Keypair> saved as
> "SydneyPharoSpeedTest.pem"
> + Clicked <Launch Instance>
> + Clicked <View Instances>
> noted instance...
> * IP address: 54.252.136.78
> * Zone: ap-southeast-2b
> * Security Group: Launch Wizard 1
>
> 4. On my Windows 10 box, in WSL did...
> $ cd ~/.ssh       # if it doesn't exist, first do...   mkdir -m 700 ~/.ssh
> $ cp /mnt/c/Users/Ben/Downloads/SydneyPharoSpeedTest.pem   ~/.ssh
> $ chmod 400 ~/.ssh/SydneyPharoSpeedTest.pem
> $ ssh -i ~/.ssh/SydneyPharoSpeedTest.pem  ubuntu at 54.252.136.78$ cat
> /etc/os-release
> ID="amzn"
> ID_LIKE="centos rhel fedora"
>
>
> GOOD NETWORK BASELINE TEST...
> Ignoring any packet loss on poor networks, first testing low bandwidths on
> a good network
> $ vi test.sh
> #!/bin/sh
> if [ -d out ]; then
>     dirdate=`stat -c %z out | awk '{print $1"-"$2}' `
>     mv out out.${dirdate}
> fi
> mkdir out
> for RATE in 1000k 500k 200k 100k 50k 20k 10k 5k 2k 1k
> do
>   echo $RATE
>   /usr/bin/time -f "%e" -o out/time.$RATE \
>        wget --quiet --limit-rate $RATE
> https://files.pharo.org/pharo-launcher/1.6/pharo-launcher-1.6.msi -O
> out/file.$RATE &
> done
>
> $ sh test.sh
> monitoring with...
> $ cat out/time* | sort -n
> $ ls -lS out
>
> results in following table and graphs...
> $RATE
> (kb/s) TIME
> (s) TIME
> (min) TIME
> (hr)
> 1000 54 1 0.0
> 500 105 2 0.0
> 200 259 4 0.1
> 100 515 9 0.1
> 50 1029 17 0.3
> 20 2576 43 0.7
> 10 5149 86 1.4
> 5 10527 175 2.9
>
> <download-speed.png>
>
> Wow that surprised me.  I'm not sure what the behaviour of file servers at
> low bandwidth should be,
> but intuitively the above seems odd.  In the past troubleshooting seems to
> have been
> focused on the cause of slow speeds, but these can occur for many reasons
> unrelated to the
> the file server.  The above test ignores cause to isolate behaviour at
> slow speeds.
>
> I forgot my own download speed yesterday (today is okay), but here is
> another sample...
> "(in Argentina) it is really slow ... 3.5KB/s ... average 10KB/s".
> http://forum.world.st/Pharo-Downloads-are-sluggish-td5084963.html
>
> I would hope that download time was near linear with speed all the way
> down to 1kb/s.
> Anyone have some sysadmins they can lean on to understand if that is
> realistic?
>
> The straightness of the line using a log-log axis makes it seem like
> policy rather than physics.
> <download-speed(log).png>
>
> HTH,
> cheers -ben
>
>
>
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