Thursday Dec 04, 2008

Doing more with less

As I have mentioned before I have an ancient Sun Ray 1 that drives the TV in our kitchen to look like a photo frame. The network is provided my an ethernet over mains bridge that is rated at 85Mbit/sec and the network drop from the server is a 1Gbit/sec. Since the switch I have is very cheap this results in a significant packet drop to that DTU with the result that the picture transition is less than ideal and can stutter somewhat.

So last night after reading an email on an internal list I finally got around to reading the documentation so I could set a bandwidth limit on this one DTU to see if things could be improved, With no bandwidth limit the very excellent utbw gives:

 lost      0/00% pkts     62 cpu   0% kbytes     53 0.021 Mbps 4.3(4.2) ms
 lost   1243/46% pkts   2652 cpu  11% kbytes   1614 0.631 Mbps 4.9(4.6) ms
 lost      0/00% pkts     60 cpu   3% kbytes     51 0.020 Mbps 4.1(4.3) ms
 lost      0/00% pkts     64 cpu   2% kbytes     55 0.022 Mbps 4.8(4.6) ms
 lost      0/00% pkts     64 cpu   2% kbytes     56 0.022 Mbps 4.2(4.7) ms
 lost      0/00% pkts     60 cpu   2% kbytes     51 0.020 Mbps 4.3(4.5) ms
 lost      0/00% pkts     62 cpu   3% kbytes     53 0.021 Mbps 4.9(4.7) ms
 lost    266/11% pkts   2393 cpu   6% kbytes   2314 0.904 Mbps 4.4(4.6) ms
 lost      0/00% pkts     60 cpu   2% kbytes     51 0.020 Mbps 4.4(4.5) ms
 lost      0/00% pkts     62 cpu   2% kbytes     53 0.021 Mbps 4.7(4.6) ms
 lost      0/00% pkts     64 cpu   3% kbytes     56 0.022 Mbps 4.1(4.3) ms
 lost      0/00% pkts     58 cpu   0% kbytes     48 0.019 Mbps 4.4(4.4) ms
 lost      0/00% pkts     62 cpu   2% kbytes     53 0.021 Mbps 6.0(5.2) ms
 lost    229/09% pkts   2377 cpu   8% kbytes   2320 0.907 Mbps 4.7(4.9) ms
 lost      0/00% pkts     60 cpu   2% kbytes     51 0.020 Mbps 4.1(4.5) ms
 lost      0/00% pkts     62 cpu   0% kbytes     53 0.021 Mbps 4.1(4.3) ms
 lost      0/00% pkts     64 cpu   2% kbytes     56 0.022 Mbps 4.2(4.2) ms
 lost      0/00% pkts     60 cpu   2% kbytes     51 0.020 Mbps 4.2(4.2) ms
 lost      0/00% pkts     62 cpu   0% kbytes     53 0.021 Mbps 4.4(4.3) ms
 lost    597/23% pkts   2532 cpu   9% kbytes   2123 0.830 Mbps 4.2(4.3) ms
 lost      0/00% pkts     60 cpu   2% kbytes     51 0.020 Mbps 4.1(4.2) ms
 lost      0/00% pkts     62 cpu   3% kbytes     53 0.021 Mbps 4.1(4.1) ms
 lost      0/00% pkts     64 cpu   0% kbytes     56 0.022 Mbps 5.1(4.6) ms
 lost      0/00% pkts     60 cpu   2% kbytes     51 0.020 Mbps 4.1(4.4) ms
 lost      0/00% pkts     62 cpu   2% kbytes     53 0.021 Mbps 4.3(4.4) ms
 lost      0/00% pkts   2133 cpu   8% kbytes   2322 0.907 Mbps 4.1(4.2) ms
 lost      0/00% pkts     60 cpu   0% kbytes     51 0.020 Mbps 7.3(5.7) ms
 lost      0/00% pkts     62 cpu   2% kbytes     53 0.021 Mbps 4.2(5.0) ms
 lost      0/00% pkts     64 cpu   2% kbytes     56 0.022 Mbps 4.2(4.6) ms
 lost      0/00% pkts     60 cpu   2% kbytes     51 0.020 Mbps 6.5(5.6) ms
 lost      0/00% pkts     62 cpu   0% kbytes     53 0.021 Mbps 4.1(4.9) ms
 lost    462/18% pkts   2509 cpu   9% kbytes   2251 0.879 Mbps 4.2(4.5) ms
 lost      0/00% pkts     60 cpu   2% kbytes     51 0.020 Mbps 4.2(4.3) ms

What is more the transition that is observed often jumps or will have one block of the picture updated after all the others. Having tuned the bandwidth down to 20Mb/sec:

 lost    114/04% pkts   2295 cpu   4% kbytes   2344 0.916 Mbps 4.4(4.7) ms
 lost      0/00% pkts     60 cpu   2% kbytes     51 0.020 Mbps 4.2(4.5) ms
 lost      0/00% pkts     62 cpu   2% kbytes     53 0.021 Mbps 7.2(5.8) ms
 lost      0/00% pkts     63 cpu   2% kbytes     53 0.021 Mbps 4.2(5.0) ms
 lost      0/00% pkts     60 cpu   0% kbytes     51 0.020 Mbps 4.4(4.7) ms
 lost      0/00% pkts     62 cpu   3% kbytes     53 0.021 Mbps 4.1(4.4) ms
 lost    216/09% pkts   2304 cpu   7% kbytes   2295 0.897 Mbps 4.4(4.4) ms
 lost      0/00% pkts     60 cpu   2% kbytes     51 0.020 Mbps 4.2(4.3) ms
 lost      0/00% pkts     63 cpu   0% kbytes     55 0.022 Mbps 4.4(4.4) ms
 lost      0/00% pkts     63 cpu   2% kbytes     53 0.021 Mbps 4.4(4.4) ms
 lost      0/00% pkts     60 cpu   2% kbytes     51 0.020 Mbps 4.1(4.2) ms
 lost      0/00% pkts     63 cpu   2% kbytes     55 0.022 Mbps 5.0(4.6) ms
 lost    168/07% pkts   2174 cpu   6% kbytes   2230 0.871 Mbps 7.0(5.8) ms
 lost      0/00% pkts     60 cpu   2% kbytes     51 0.020 Mbps 4.9(5.3) ms
 lost      0/00% pkts     62 cpu   2% kbytes     53 0.021 Mbps 5.9(5.6) ms
 lost      0/00% pkts     63 cpu   2% kbytes     56 0.022 Mbps 4.1(4.9) ms
 lost      0/00% pkts     60 cpu   0% kbytes     51 0.020 Mbps 4.5(4.7) ms
 lost      0/00% pkts     62 cpu   2% kbytes     53 0.021 Mbps 4.2(4.5) ms
 lost      0/00% pkts   1938 cpu   8% kbytes   2118 0.827 Mbps 4.3(4.4) ms
 lost      0/00% pkts     60 cpu   0% kbytes     50 0.020 Mbps 8.4(6.4) ms
 lost      0/00% pkts     62 cpu   2% kbytes     52 0.021 Mbps 17.7(12.1) ms
 lost      0/00% pkts     64 cpu   2% kbytes     55 0.022 Mbps 4.2(8.1) ms
 lost      0/00% pkts     60 cpu   2% kbytes     50 0.020 Mbps 6.3(7.2) ms
 lost      0/00% pkts     62 cpu   0% kbytes     52 0.021 Mbps 4.4(5.8) ms
 lost    214/09% pkts   2224 cpu   7% kbytes   2170 0.848 Mbps 4.0(4.9) ms
 lost      0/00% pkts     60 cpu   2% kbytes     50 0.020 Mbps 4.1(4.5) ms
 lost      0/00% pkts     62 cpu   2% kbytes     52 0.021 Mbps 4.6(4.6) ms
 lost      0/00% pkts     64 cpu   0% kbytes     55 0.022 Mbps 5.7(5.1) ms
 lost      0/00% pkts     60 cpu   2% kbytes     50 0.020 Mbps 4.6(4.8) ms
 lost      0/00% pkts     64 cpu   2% kbytes     55 0.022 Mbps 5.8(5.3) ms
 lost    194/08% pkts   2278 cpu   9% kbytes   2274 0.888 Mbps 4.2(4.8) ms
 lost      0/00% pkts     60 cpu   0% kbytes     50 0.020 Mbps 4.2(4.5) ms
 lost      0/00% pkts     63 cpu   2% kbytes     53 0.021 Mbps 4.2(4.3) ms
 lost      0/00% pkts     63 cpu   3% kbytes     53 0.021 Mbps 4.2(4.3) ms
 lost      0/00% pkts     60 cpu   1% kbytes     50 0.020 Mbps 4.9(4.6) ms
 lost      0/00% pkts     62 cpu   1% kbytes     52 0.021 Mbps 4.1(4.3) ms
 lost      0/00% pkts   2149 cpu   6% kbytes   2319 0.906 Mbps 4.3(4.3) ms
 lost      0/00% pkts     60 cpu   2% kbytes     50 0.020 Mbps 4.2(4.3) ms

The numbers improve greatly however they hide the truth somewhat. Since the operation of the picture frame is that except for the clock that updates every second there are no updates at all for most of the time then every 2 minutes a new photo is displayed. So those averages which appear to be every 20 seconds hide the very high burst of data that happens.


You can see the difference here:

100Mb/sec:

10Mb/sec

Tuesday Nov 06, 2007

17" Wide screen Sun Ray Photo Frame

I've briefly mentioned before that we have had the builders in recently and at last we are reaching the final few steps. This includes an LCD TV for the kitchen mounted on the wall. I'm sure you all know, modern LCD TV's all have an input for a computer. So I must be the last of millions to turn my LCD TV into a 17” photo frame powered by a Sun Ray 1 and some ethernet over mains plugs.

With SRSS 4.0 I can, although so far have not, have kiosk mode running just on this one Sun Ray although since everyone in the house has a smart card there is not really any need.

The “photo frame” software is no more than a proof of concept. A script that finds all my photos (about 3000) and uses display(1) to display them. Still need to confirm I have turned off he screen saver, no point in waiting for keyboard or mouse input as the Sun Ray has none and is quite well hidden. Also ideally it needs to have better transitions for the pictures and a way of controlling it. I can see a USB infra red receiver and remote control so that I can select that bike porn channel on demand.

The upgrade of the SRSS software would have been so much simpler if I had:

  1. Read the manual first.

  2. Rebooted when the documentation told me to. I hate rebooting, it is just so Windows but it really did seem to be required.

  3. Read the manual first.

There are however one issue. Kiosk mode does not seem to work with JDS on build 76, which I think is a know bug.

Given that a Sun Ray 1 on ebay is £25, this has to be a really cheap photo frame and this is a 17” wide screen photo frame. In fact the ethernet plug was more than the Sun Ray.

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This is the old blog of Chris Gerhard. It has mostly moved to http://chrisgerhard.wordpress.com

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