[Pharo-dev] Spotter shortcut reset

ducasse stepharo at netcourrier.com
Sun Feb 3 10:12:11 EST 2019


I asked christophe to not miss your email and see if this is something from our side. 

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 <mailto:stepharo at netcourrier.com>> wrote:
> > On Sat, 2 Feb 2019 at 11:01, Ben Coman <btc at openinworld.com <mailto: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/ <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 <mailto: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 $RATE https://files.pharo.org/pharo-launcher/1.6/pharo-launcher-1.6.msi <https://files.pharo.org/pharo-launcher/1.6/pharo-launcher-1.6.msi> -O out/file.$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 <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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