Odroid emmc speeds

I’ve found out this link that shows some speed benchmarks, on the Raspeberry PI, for some SD cards and disks: RPi SD card benchmarks.

For comparison, my data:

Odroid C1+ with 32GB emmc:

root@odroid:~# hdparm -T /dev/mmcblk0p1 
 Timing cached reads:   1494 MB in  2.00 seconds = 746.46 MB/sec

My Seagate 2TB on my DS212+, also driven by an ARM processor:

root@DiskStation:/volume1/homes/root# hdparm -T /dev/sda1

 Timing cached reads:   832 MB in  2.00 seconds = 415.24 MB/sec

The flash pen that holds the operating system on my old and faithful NSLU2:

root@nslu2:~# hdparm -T /dev/sda1

Timing buffer-cache reads:    78 MB in 0.51 seconds = 155972 kB/s

And finally my Crucial SSD disk on my desktop computer:

[root@pcortex:~]# hdparm -T /dev/sdc2

 Timing cached reads:   16804 MB in  2.00 seconds = 8408.63 MB/sec

The conclusion? Not bad for the emmc. Recommended over an SD card? I think definitely. Expensive? Well, yes…

Linux: Slow or unbearable performance with high memory usage applications

Well this post title is a bit vague because the issue that have affected me can have several sources, not just the one that I’ll describe. But I suppose the solution is the same independently for all sources.

Anyway, I was suffering from a strange problem on both my computers, the desktop has 6GB of RAM, and the laptop, 16GB.

On the desktop machine, where I use KDE 4 on Arch Linux, the desktop can froze when using some resource intensive applications like Google Maps on Firefox or Chromium and Android Studio. When the frozen desktop situation happens, I just have to wait a few minutes, during which time, the keyboard is irresponsible and the mouse is “jumpy”, or doesn’t work at all. And so after a while, one random application, that could be anything, including the desktop, is killed, with some cryptic message regarding sacrifice on the system logs…

Anyway, on the Desktop, due to the fact that I’ve upgraded the main disk to an SSD, I didn’t enabled the swap partition. And that was one of the main reasons of this behaviour that I was having. Despite having 6GB of RAM, a swap file is good to have, and so I’ve used a swap partition on one of the spinning disks.

That apparently stopped the issues on the desktop and it never froze like it used to when performing the same tasks.

On the laptop it was another matter, mainly because of the fact that it only has a 120GB SSD disk, and no spinning disks, I had no swap file/partition created or enabled. I though that with 16GB of RAM, why bother… but due to professional related activities, I had to start to work with the HortonWorks HDP 2.3 big data/hadoop platform, and that is a heavy resource hog…

So, despite of having 16GB of RAM available, the Hadoop virtual machines based on Vmware could make the computer just froze for lenghty periods of time, just like my desktop computer.

But, now I know that was related to fact that I didn’t have a swap partition/file, and so I’ve created one.

The swap file solution for this specific case didn’t solve completely my issue, but I did managed to see a process named khugepaged consuming huge amounts of CPU.

And that was the reason that I had for my frozen desktop and virtual machine for some lengths of time.

So I’ve disable the Huge Page support on my host operating system, AND on my guest CentOS virtual machine that is running HDP 2.3:

[root@dune:cortex]# cat /sys/kernel/mm/transparent_hugepage/enabled
[always] madvise never
[root@dune:cortex]# echo never > /sys/kernel/mm/transparent_hugepage/enabled

[root@dune:cortex]# echo never > /sys/kernel/mm/transparent_hugepage/defrag
[root@dune:cortex]# cat /sys/kernel/mm/transparent_hugepage/enabled          
always madvise [never]

More info can be obtain here:


So this might not be the magic bullet if we are having desktop freezes, and not using huge amounts of RAM, but it might help.

md5deep and hashdeep on Synology DS212+

My personal photos are located at my desktop computer, and I have backups of them on my Synology DS212+ and my old faithful Linksys NSLU2 with an external disk.

The issue that I have now is that to keep backup times short I only backup the current year, because, well, the other years are static data. Previous years are already backed up and that data is not to get modified. Right? So what if corruption happens? How do I detected it? How can I be warned of such event? Right now I have no method to check if my digital photos of 2003 are totally intact in all of my three copies. And if  I detect corruption on one bad file/photo, which file is the correct one?

So I’m investigating this issue, and one of the tools available to create checksums and then to verify if everything is ok and no corruption has appeared is the md5deep and hashdeep programs. These are available as sources at this link: http://md5deep.sourceforge.net/start-hashdeep.html

These are the instructions for cross compiling these tools for the ARM based Synology DS212+. As usual this is done on a Linux Desktop/server machine.

1st) Set up the cross-compiling environment: Check out this link on the topic: https://primalcortex.wordpress.com/2015/01/04/synology-ds-crosscompiling-eclipseibm-rsmb-mqtt-broker/

2nd) Setting up the cross compiling environment variables is now a bit different:

export INSTALLDIR=/usr/local/arm-marvell-linux-gnueabi
export TARGETMACH=arm-marvell-linux-gnueabi
export BUILDMACH=i686-pc-linux-gnu
export CROSS=arm-marvell-linux-gnueabi
export CC=${CROSS}-g++
export LD=${CROSS}-ld
export AS=${CROSS}-as
export AR=${CROSS}-ar
export GCC=${CROSS}-g++
export CXX=${CROSS}-g++

We will use the C++ compiler.

3rd) Create a working directory and clone the repository to your local machine: git clone https://github.com/jessek/hashdeep.git
4th) Change to the hashdeep directory and execute the following commands:

[pcortex@pcortex:hashdeep]$ sh bootstrap.sh
[pcortex@pcortex:hashdeep]$ ./configure –host=arm-marvell-linux-gnueabi
[pcortex@pcortex:hashdeep]$ make

And that’s it. If everything went well then at hashdeep/src directory the commands are available:

[pcortex@pcortex:src]$ file hashdeep
hashdeep: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.3, for GNU/Linux 2.6.16, not stripped

We can now copy the commands to the DiskStation and start using them.

Now all I need is to devise a method that creates and checks each year photo hash/signatures, and warns me if a difference is detected. I’m thing on using the audit mode of the hashdeep command, and do each day a check for one year, for example, on Mondays check 2003 and 2013, on Tuesday check 2004 and 2014 and so on.

Arch Linux e Cartão do Cidadão

Só um quick post para lembrar como se pode por o Midleware/software do cartão do cidadão a funcionar em Arch Linux.

– Primeiro determinar que o cartão é detectado pelo sistema:

Bus 007 Device 002: ID 058f:9520 Alcor Micro Corp. EMV Certified Smart Card Reader

– Segundo instalar o software opensc:

[root@pcortex ~]# pacman -S opensc

Isto só vai servir para verificar que conseguimos aceder correctamente ao leitor do cartão.

– Testar o acesso ao leitor:

[root@pcortex ~]# opensc-tool -l
No smart card readers found.

Se for este o caso, arrancar com o daemon de suporte de acesso aos leitores:

[minime@pcortex ~]# sudo -s
[root@pcortex ~]# pcscd

Testar novamente:

[minime@pcortex ~]# opensc-tool -l
# Detected readers (pcsc)
Nr. Card Features Name
0 No Alcor Micro AU9520 00 00

– Podemos agora instalar o software do cartão do cidadao. No meu caso usei a versão disponível no repositório AUR:

yaourt -S cartao-cidadao

E no fim, executa-se:

[minime@pcortex ~]# pteigui

Pode-se ignorar as mensagens de erros, e o icon deverá aparecer no SysTray.

Para ter acesso aos certificados do cartão a partir do FireFox, por exemplo, bastará em princípio seguir estas instrucções: https://faqs.up.pt/faq/content/29/557/pt/como-configurar-o-mozilla-firefox-para-usar-o-cart%C3%A3o-de-cidad%C3%A3o.html

Node-Red: Push Notifications to Google Cloud Messaging GCM

The following instructions will allow Android devices to receive notifications from Node-red flows using the Google Cloud Messaging infra-structure. This is achieved by using the Node-js library for accessing GCM (Google Cloud Messaging) node-gcm.

Installing node-gcm:

We need to install the Google Cloud Messaging node supporting module either locally on Node-red or globally. If installing locally just cd to the node-red directory and do npm install node-gcm. Globally the command needs the -g switch added like this: sudo npm install node-gcm -g.

Configuring Node-red:

To be possible to invoke functions from Node-gcm from Node-red steps, like functions, we need to make the node-gcm module available. For that go to the base directory of Node-red and edit the settings.js file.

Modify the file so that the following configuration is now defined:

functionGlobalContext: {
// os:require('os'),
// bonescript:require('bonescript'),
// arduino:require('duino')
Starting up Node-red and our first push notification to GCM:
Start up Node-red by using the command line: node red.js -s settings.js . It’s important and imperative that we now start uo with the modified settings.js file or some other file with the above configuration.
We can now add a function step with the following code to push a notification:
var gcm = context.global.gcm; /// Define our message: var message = new gcm.Message({ collapseKey: 'node-red', delayWhileIdle: true, timeToLive: 3, data: { key1: 'Node-Red Notification', key2: 'Hello android from Node-red' } }); // Set up the sender with you API key var sender = new gcm.Sender('AIza...');  // Replace with your KEY!!!!! // Add the registration IDs of the devices you want to send to var registrationIds = []; registrationIds.push('APA.....');  // Replace with your device registration ID!!!!! // Send the message // ... trying only once sender.sendNoRetry(message, registrationIds, function(err, result) { if(err) console.error(err); else     console.log(result); }); return msg;
And that’s it. Note that on the Data JSON object the key names, key1 and key2 are arbitrary. The keys can have any valid name as long that the receiving application knows about them.
For testing I’m using an inject node to activate the above function and I can see at the console (Not on the Debug tab) the following:
{ multicast_id: 9123452345452345, success: 1, failure: 0, canonical_ids: 0, results: [ { message_id: '0:7957832452%3676573df353' } ] }

If you receive other messages, like failure:1, there is something wrong with your Google GCM key or your registration device id is invalid.

For example:

{ multicast_id: 5439642763222344000, success: 0, failure: 1, canonical_ids: 0, results: [ { error: 'InvalidRegistration' } ] }

This means that the registrationId.push value doesn’t belong to any registered device to our GCM project.

If you just receive 401 that means that you’re using an Invalid Browser GCM key. Check the Google developer console to get the correct key.


I’ve done my basic testing with the sample Google GCM client available at https://code.google.com/p/gcm/source/checkout.

I’ve used Android Studio and the provided gcm-client source code to compile and test the communication.

The problem with the above gcm-client code is that we need first to compile and deploy at the device (or emulator) to make the GCM client application to at least run at least once to get the registration id of the device, so that we can provide the registration key to the above node-red code.

We also can change the provided Google code to send to Node-red the registration ID. This process alows devices to inform the Node-red flows of their registation ID, and for that we need to change the gcm-client program adding a registration process and a registration server on our side.

Upgrading to an SSD, moving from Kubuntu to Arch Linux and setting up KDE

This is a single post just to make notice of some points:

My home desktop PC, was running since 2009 the Kubuntu distribution. I’ve never reinstalled it and did always the upgrades from 8.10 to 9.04, 9.10 and so on until 14.04. Almost six (!) years with no virus, trojan horses, and a single initial installation. I’ve upgraded through the years the KDE desktop since the ill famed initial 4.0 release, to the latest 4.6 release.

But things where starting to go awry… At the beginning I had a ATI 4870 graphic board, but ATI dropped support for it on Linux (and Windows) and since I had so many troubles with the proprietary driver, and to add it up I had no support for the board, I sold it and bought an Nvidia GTX660.

But with both graphic boards, I had suffered from a long time problem: I could only do a sleep/resume a number of times before the system hanged. The symptoms starting from loosing network connectivity and then restoring right back, and some cycling of these symptoms to a complete lockup. At first I thought that was due to the network driver used by my motherboard, a Asus P6T with  a Realtek RTL8111/8168/8411 board, but with the correct driver for it, the issue continued.  Booting up was a painful two/three minute wait from BIOS to desktop.

But after a while I could pin point my issues not to the network board but to the Xorg and video driver combination. Some EQ buffer overflow, hanged X, and finally the machine.

Ubuntu and Kubuntu based distributions have PPA’s repositories where some alternative software and versions of mainstream software are available. I had trouble with some of these alternative PPA’s when upgrading, and had to remove them (with ppa-purge) to be able to upgrade the Kubuntu distribution. Anyway, there is an PPA, xorg-edgers,  where alternative and more recent versions of Xorg Software and Nvidia drivers are provided and that almost solved my sleep/resume problem. The problem was that after adding this PPA the Ubuntu/Kubuntu nvidia driver and the Xorg-edgers driver, after updates the X server was unable to find the nvidia driver, despite being installed, and had to reinstall the driver again to get my desktop working.

That was it. I had enough with Ubuntu/Kubuntu distributions. My bad and my issues, sure…

I’ve being testing Arch Linux on my work laptop for almost an year with great success. I’ve chosen Arch Linux because I didn’t had to loose an unknown number of hours per year upgrading to the next distribution version, and an rolling release version makes more sense. And Arch has the greatest Linux Wiki out there even solving problems that happen on the Ubuntu/Kubuntu line, and also mainly there are only one (well two) repositories. No PPA’s mess.

So I completely moved all my systems to Arch Linux, and my sleep/resume issue is 100% solved.

SSD on a SATA II based motherboard

My desktop computer has an Asus P6T motherboard. This motherboard only has SATA II (SATA 2) ports. Is it worth to use an SSD on such a board without upgrading to a SATA III board?

The answer is YES. If you have a SATA II based motherboard AND not buying an SSD because of that, do not wait any more. Buy it now. It is totally worth it.

Arch Linux is of course way lighter than Kubuntu, and with an SSD ( by the way it’s a Crucial MX100 256GB) my two/three minute boot to desktop time came down to 15s…

hdparm -Tt /dev/sdc
Timing cached reads:   16710 MB in  2.00 seconds = 8361.40 MB/sec
Timing buffered disk reads: 728 MB in  3.00 seconds = 242.59 MB/sec

Note the Samsung EVO 120GB that I have on my work computer, that has the flawed firmware that slows down with time, on a SATA III based motherboard:

Timing cached reads: 23864 MB in 2.00 seconds = 11943.41 MB/sec
Timing buffered disk reads: 164 MB in 3.01 seconds = 54.47 MB/sec

Compare this with my desktop old boot disk, an WD 640GB blue:
Timing cached reads: 16580 MB in 2.00 seconds = 8296.87 MB/sec
Timing buffered disk reads: 356 MB in 3.00 seconds = 118.59 MB/sec

I hadn’t yet had the time to upgrade the firmware on the EVO…

Making KDE looking good on Arch Linux

To end this rather long and tedious post, and also to my future reference, to make KDE looking good:

    • Make sure that the infinality modifications are installed: https://wiki.archlinux.org/index.php/Infinality. Make sure that you update.
    • Make sure that the DPI detected by your X server are correct for your monitor. Install xdpyinfo with pacman -S xorg-xdpyinfo. Figure out what might be your monitor dpi using this site: http://dpi.lv/ . Execute xdpyinfo | grep -B2 resolution and see if are similar. If not you need to set the correct dpi either in xorg.conf or in the Kde settings.
      In my case I have a dual monitor setup, and hence the weird dpi 95×96.screen

      #0: dimensions: 3200×1080 pixels (856×286 millimeters)

      resolution: 95×96 dots per inch

      So my font settings are:


  • While the above settings make my fonts look good, the taskbar fonts where awful and took me a while to figure out that was not the dpi settings but the Desktop Theme.
  • To solve this first install Krita with pacman -S calligra-krita . This will install the Krita color themes that are, in my opinion very good. And on KDE System Settings -> Workspace Appearance -> Desktop Themes select Get New Themes and get the AndroidBit theme.
  • That’s it:Selection_004
  • I’ve selected the Produkte Desktop Theme
  • And the colors:Selection_005

ESP8266: Setting up native SDK’s on Linux and exploring some applications

The information for installing and setting up the native SDK for the esp8266 from Expressif is readily available in the Internet:

With the native SDK we can develop our own firmware using the Espressif SDK and the C or C++ language. Then we can use directly the internal esp8266 processor, allowing to do interesting things in a more direct way, like implementing MQTT, driving hardware, and so on.

So why this post?  Basically is to put into writing some of my own annotations to the issues that I had installing the SDK and the cross compiler tools on my Linux machines.

Starting up:

The original instructions that I’ve followed where these: https://github.com/esp8266/esp8266-wiki/wiki/Toolchain
I installed the tool chains in two computers, both running Linux: an Arch Linux distribution and a Kubuntu 14.04 distribution (and time is up for this one because I’m moving it also to Arch Linux. All I’m missing is to install a SSD).

1st) Installed the required pre-requisites that are documented on the above link. On Arch Linux the package installation tool is pacman and probably the package names can be different. I didn’t need to install anything on Arch, but on Kubuntu I needed to install the 64-bit pre-requisites.

2nd) Create the /opt/Espressif directory. The owner should already be your user, except if you have no permissions on the /opt directory.

3rd) Install the Xtensa Crosstool-NG that has the cross compiler and tools for the esp8266 processor:

cd /opt/Espressif
git clone -b lx106-g++ https://github.com/jcmvbkbc/crosstool-NG.git
cd crosstool-NG
./bootstrap && ./configure --prefix=`pwd` && make && make install
./ct-ng xtensa-lx106-elf
./ct-ng build

Some notes regarding this:

  •  We are going to clone the git branch lx106-g++ that has the C compiler and the C++ compiler. There is another branch named lx106 that only has the C compiler.  There is some software out there like Ardunet that need the c++ compiler and so that is the reason why I’ve chosen this git branch.
  • I’ve also changed the url for the git repository from git:// to https:// because in I’m behind a web proxy that needs authentication. Just make sure that the http_proxy, https_proxy and ftp_proxy variables are set. The ftp_proxy variable is needed because at the ct-ng build step will connect to a ftp server to retrieve files. One example for setting these environment variables: export https_proxy=http://myproxyuser:myproxypass@proxyip:port. If you have an internet direct connection, like at home, no need to set these variables.
  • The ./ct-ng build step will take a long time, around 30 minutes in one of my computers and 15 in another.
  • The tool will connect to the ftp server on IP: where are located the Gnu compiler sources.

At the end we need to add the path to the crosstools to our PATH variable.
export PATH=/opt/Espressif/crosstool-NG/builds/xtensa-lx106-elf/bin/:$PATH
You may want to add this line at your .bashrc file. In my case (I’m using KDE desktop, I’ve created a Konsole profile for this type of work and add the new settings to the PATH variable,)

Installing the Expressif SDK

The instructions on the above link are for the 0.9.3 version of the SDK. I’ve installed the most recent version at this time that was 0.9.4:

cd /opt/Espressif
wget -O esp_iot_sdk_v0.9.4_14_12_19.zip https://github.com/esp8266/esp8266-wiki/raw/master/sdk/esp_iot_sdk_v0.9.4_14_12_19.zip
unzip esp_iot_sdk_v0.9.4_14_12_19.zip
mv esp_iot_sdk_v0.9.4 ESP8266_SDK
mv License ESP8266_SDK/
cd /opt/Espressif/ESP8266_SDK
wget -O lib/libc.a https://github.com/esp8266/esp8266-wiki/raw/master/libs/libc.a
wget -O lib/libhal.a https://github.com/esp8266/esp8266-wiki/raw/master/libs/libhal.a
wget -O include.tgz https://github.com/esp8266/esp8266-wiki/raw/master/include.tgz
tar -xvzf include.tgz

Except the change of the SDK version, the instructions are the same as the original reference post.

Installing the esptool

The esptool will pick up the compiler output and extract/create the files needed for flashing the esp8266. The instructions for this step are the same as in the original reference post. In my case, I’ve got the tool from the sources and not installed the deb file:

cd /opt/Espressif
wget https://github.com/esp8266/esp8266-wiki/raw/master/deb/src/esptool_0.0.2.orig.tar.gz
tar xvzf esptool_0.0.2.orig.tar.gz
cd esptool

Let’s put the tool on the search path. In my case I’ve choose the Xtensa bin directory. (Edit: it should be put at /usr/bin. See below at building the blinky example)

cd /opt/Expressif/esptool
chmod +w /opt/Espressif/crosstool-NG/builds/xtensa-lx106-elf/bin
ln -s /opt/Espressif/esptool/esptool ../crosstool-NG/builds/xtensa-lx106-elf/bin
sudo cp /opt/Espressif/esptool/esptool /usr/bin

Installing the firmware uploader tool esptool-py

cd /opt/Espressif
git clone https://github.com/themadinventor/esptool esptool-py
chmod +w /opt/Espressif/crosstool-NG/builds/xtensa-lx106-elf/bin
ln -s /opt/Espressif/esptool-py/esptool.py crosstool-NG/builds/xtensa-lx106-elf/bin/

With this tool we can upload the generated firmware into the esp8266.


So now we are ready and we can follow the instructions here: https://github.com/esp8266/esp8266-wiki/wiki/Building to starting building things.

There are some code examples, one of them named blinky but the make file assumes that the esptool is located /usr/bin. This is because I’ve not installed the esptool through the deb package. So we can copy the esptool command to the /usr/bin directory: sudo cp  /opt/Espressif/esptool/esptool   /usr/bin.

We can now build the AT demo and the IoT demo. Just follow the instructions. For example for the IoT example just do the following (Make sure that the path is set: export PATH=/opt/Espressif/crosstool-NG/builds/xtensa-lx106-elf/bin/:$PATH):

cd /opt/Espressif/ESP8266_SDK
sed -i -e 's/xt-ar/xtensa-lx106-elf-ar/' -e 's/xt-xcc/xtensa-lx106-elf-gcc/' -e 's/xt-objcopy/xtensa-lx106-elf-objcopy/' Makefile
mv examples/IoT_Demo .
cd /opt/Espressif/ESP8266_SDK/IoT_Demo 
cd .output/eagle/debug/image
esptool -eo eagle.app.v6.out -bo eagle.app.v6.flash.bin -bs .text -bs .data -bs .rodata -bc -ec 
xtensa-lx106-elf-objcopy --only-section .irom0.text -O binary eagle.app.v6.out eagle.app.v6.irom0text.bin 


For uploading just follow the instructions here: https://github.com/esp8266/esp8266-wiki/wiki/Uploading but basically is using the esptool.py to upload the firmware to the esp8266. Just make sure tha GPIO0 is grounded at boot time.

The IoT RTOS based example:

There is a beta SDK for the esp8266 based on the freeRtos according to this: https://github.com/espressif.

To use this SDK (Make sure that the PATH environment variable is correctly defined):

cd /opt/Expressif
git clone https://github.com/espressif/esp_iot_rtos_sdk.git
git clone https://github.com/espressif/esp_iot_rtos_sdk_lib.git
cp esp_iot_rtos_sdk_lib/lib/*  esp_iot_rtos_sdk/lib
cd esp_iot_rtos_sdk


We should have now the IoT RTOS main image ready. To generate the firmware files:

cd app/.output/eagle/debug/image/
esptool -eo eagle.app.v6.out -bo eagle.app.v6.flash.bin -bs .text -bs .data -bs .rodata -bc -ec
xtensa-lx106-elf-objcopy --only-section .irom0.text -O binary eagle.app.v6.out eagle.app.v6.irom0text.bin

And we can flash it:

/opt/Espressif/esptool-py/esptool.py --port /dev/ttyUSB0 write_flash 0x00000 eagle.app.v6.flash.bin 0x40000 eagle.app.v6.irom0text.bin

The default baud rate for the IoT example is 74880…

 Exploring some application:

Now that we have all the tools for developing natively we can check out some applications:

  • esp-mqtt – A native MQTT client for the esp8266
  • Ardunet – A work in progress that mimics the Arduino way of making applications on the esp8266.

The download links are:


For building it, first change your connection parameters at include/user_config.h

cd /opt/Espressif
git clone https://github.com/tuanpmt/esp_mqtt.git
cd esp_mqtt
cp Makefile.linux Makefile
make flash


For building it:

cd /opt/Espressif
git clone https://github.com/Karang/Ardunet.git
cd Ardunet
cp -R /opt/Espressif/esp_iot_rtos_sdk/ld .
cd /opt/Espressif/Ardunet/src/.output/eagle/debug/image
esptool -eo eagle.app.v6.out -bo eagle.app.v6.flash.bin -bs .text -bs .data -bs .rodata -bc -ec
xtensa-lx106-elf-objcopy --only-section .irom0.text -O binary eagle.app.v6.out eagle.app.v6.irom0text.bin

And we can flash it.


So after this long post I hope that things now are a bit more documented from the installation and setting up point of view.