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memory

no talloc stackframe at ../source3/param/loadparm.c:4864, leaking memory

As I upgrade to 14.04, I started seeing this error in my console:

no talloc stackframe at ../source3/param/loadparm.c:4864, leaking memory

Quite cryptic if you ask me, but the "leaking memory" did sound bad.

The error would in particular appear when I used sudo for whatever reason, for example:

sudo iptables -L -nvx

So... something to do with sudo?

I found the answer on the Ubuntu forum. The solution is to turn off a feature of samba. Run the samba setup tool in your console:

sudo pam-auth-update

That opens a curses window in your console. You should then see an option ...

CUDA on NVidia Quadro 600

As I'm slowly learning CUDA, I got some of the tests running. Those under 1_Utilities actually define the parameters (stats) of the card. There are the parameters for an NVidia Quadro 600:

Device 0: "Quadro 600"
  CUDA Driver Version / Runtime Version          5.0 / 5.0
  CUDA Capability Major/Minor version number:    2.1
  Total amount of global memory:                 1024 MBytes (1073283072 bytes)
  ( 2) Multiprocessors x ( 48) CUDA Cores/MP:    96 CUDA Cores
  GPU Clock rate:                                1280 MHz (1.28 GHz)
  Memory Clock rate:                      ...

Fast render from image A to image B using alpha for blending

The attached package currently includes a C function and a SIMD function that both are used to blend two images together.

At this point I do not like the fact that the result is invalid (1 off with large values—if you have an alpha of 255, then you are likely to get the source component value minus 1). Outside of that, it works nicely and it is VERY fast.

I can blend 3,300 NTSC images per second with my i5 (Intel(R) Core(TM) i5 CPU 760 @ 2.80GHz.) With my newer computers I can run 3,750 NTSC images per second. These have Xeon processors (Intel(R) Xeon(R) CPU E31220 @ 3.10GHz.) The ...

Updating the BIOS on my GA-P55A-UD4P exclusively running Linux

Server Memory Upgrade

I got some new memory for my GA-P55A-UD4P motherboard. It is supposed to support 16Gb of RAM: sweet!!!

So, I got some Kingston which in general the Gigabyte motherboards support. (I had some before.)

I turned off the server and then the powersupply1.

I remove the 2 x 2Gb of RAM and install the new 4 x 4Gb sticks. Make sure it's well sited multiple ...

  • 1. I have one of those power supply you can turn off, there is a switch on it... Without doing so, I can still see some lights on the network connectors meaning that electricity is still running in the machine!

Testing your memory on a live Linux system

Today I wanted to test the memory on a remote server. I could not just reboot and run memtest86+ so instead I had to look for a different solution to testing most of the computer memory without having to reboot...

I found an interesting page in that regard describing a way to do so using md5sum on a very large file.

The is a verbatim copy of the Linux command line proposed.

  dd if=/dev/urandom bs=768304 of=/tmp/memtest count=1050
   md5sum /tmp/memtest; md5sum /tmp/memtest; md5sum /tmp/memtest

The size, 768304 is expected to be close to your memory size. You should know how much memory

Load Average, to know how busy your server is

Whenever you run many applications on a server, such as many instances of your web server (i.e. Apache), you may want to know how much of the system is being used. This can be important to avoid overloading your system.

The load is computed by the kernel. The kernel knows how many processes are running and how much processing power your server has (i.e. how many processors.) With that information, it infers how many processes are being held back for a period of time. The default periods are 1, 5 and 15 minutes (I'm sure you can recompile your kernel with different timings!)

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CVS and really large files

Yesterday, I got a nice little surprise...

I inadvertendly added two copies of an uncompressed MS-Access data in my CVS. The files were over 400Mb (about 434Mb if I'm correct.) This started okay, then slowly I could see my memory going banana.

Wow! It took a good 20min. to check-in. My CVS is on my computer, so it is not the transfer that's slow... The fact is, the allocated a buffer for the entire file! My computer was on its knees!

at job spool growing

How it works

The at command is often used to start a process at a later time. It can run any script at a specified date and time.

For instance, if you want the computer to send you a signal in one hour, use something like:

cat signal | at -q z now + 60 minutes

Assuming that the file named signal contains the commands necessary to generate the signal. Then in 60 minutes, the script will be execute and the signal will be heard or shown.

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