Operation Costs Measured in CPU Clock Cycles

, 1 min read

I have written on the merits of 64-bit vs 32-bit, or on the AMD Bulldozer CPU Architecture Overview. An article in ithare.com gave a very good overview about the relative performance of various CPU operations. Below is the graphic: The above image is from IT Hare on Soft.ware. Also see the often…

Statistics of this Blog: Crossed 40.000 Views

, 1 min read

This blog was viewed more than 40.000 times and had more than 30.000 visitors. As in this post, here are the numbers: All these increases by 10.000 views all come roughly every eight months, see 30.000 (Jan-2016), 20.000 (Apr-2015), 10.000 (Sep-2014). So I kind of have reached a steady-state. The…

Bluetooth Headphones in Arch Linux

, 2 min read

There is a big difference between noise-cancelling headphones, and classical headphones without noise-cancelling ability! Especially when you use them in a noisy environment, like a plane or a large office bureau. Inspired by a positive review of the Bose headphones by Marques Brownlee, I bought…

Running bacman in parallel

, 4 min read

The mailing list for pacman-dev contains an interesting thread when rebuilding packages from source, i.e., running bacman in parallel. Gordian Edenhofer ran some tests on performance when running one, two, three, up to six jobs in parallel. The results, below, clearly show that using all your cores…

Interior of Dell XPS-13 and Acer Aspire

, 1 min read

Here is a photo when the Dell XPS-13 is opened: And here is the Acer Aspire opened:

Why does deep and cheap learning work so well?

, 8 min read

Very interesting. -- -- -- Quote -- -- -- Why does deep and cheap learning work so well Lin & Tegmark 2016 Deep learning works remarkably well, and has helped dramatically improve the state-of-the-art in areas ranging from speech recognition, translation, and visual object recognition to…

Setting Keyboard-Language in IceWM

, 1 min read

If you start IceWM from GNOME, you can set your language settings in ~/.icewm/startup For example #!/bin/sh setxkbmap de Setting all available window-managers is done in /usr/share/xsessions Example: For starting icewm you can use the following configuration file…

LibreOffice Impress Becoming Very Slow After Copy/Paste

, 1 min read

LibreOffice Impress version 5.1 and 5.2 for Linux kernel 4.7 becomes extremely slow, if one copies some slides multiple times. This behaviour can be reproduced on laptops, machines with and without graphic card. For example, take a random presentation and copy one slide 20 times by pressing ctrl-v.…

SSD Speed on Dell XPS 13 9350

, 1 min read

In Hard-Disk and SSD Speed Comparisons I compared a Mushkin SSD with 60 GB against a ADATA with 128 GB against a Seagate 1 TB hard disk drive. The SSD's had roughly three times the speed of the hard disk drive. I.e., 380 MB/s vs. 134 MB/s for reading Mushkin vs. Seagate, and 297 MB/s vs. 131 MB/s…

Considerations when converting from WordPress.com to Hugo

, 2 min read

At times WordPress.com uses its user base to experiment with some half baked new features, see for example Classical editor in WordPress.com, or see this Hello Jekyll, bye Wordpress.com! These are the times when I consider migrating from WordPress.com to another blogging platform. Usually after…

Exporting Exchange/Outlook GAL to vCard

, 2 min read

This post is about the Microsoft Exchange GAL, i.e., the global address list. The task is to export the data in the GAL to vCard format. Microsoft Outlook stores local caches of the GAL in %userprofile%\Local Settings\Application Data\Microsoft\Outlook, see Administering the offline address book in…

GCC 6.1 Compiler Optimization Level Benchmarks

, 1 min read

In Effect of Optimizer in gcc on Intel/AMD and Power8 I measured speed ratios between optimized and non-optimized C code of three on Intel/AMD, and eight on Power8 (PowerPC) for integer calculations. For floating-point calculations the factors were two and three, respectively. Michael Larabel in…

Convert ASCII to Hex and vice versa in C and Excel VBA

, 3 min read

In Downloading Binary Data, for example Boost C++ Library I already complained about some company policies regarding the transfer of binary data. If the openssl command is available on the receiving end, then things are pretty straightforard as the aforementioned link shows, in particular you then…

No YouTube Videos on Google Chrome v50

, 2 min read

After upgrading to Google Chrome version 50 I could hear sound in YouTube videos, but no images/video. At first I thought this was a matter just affecting me. Now I noticed that another machine which I upgraded to Google Chrome v50 also lost the ability to watch video in YouTube. This other machine…

Upgrading from OxygenOS 1.0.3 to 2.1.4 on the OnePlus One Smartphone

, 4 min read

This short guide describes how to upgrade your OnePlus One Smartphone from OxygenOS version 1.0.3 to 2.1.4. In this case the initial version of your OS is of no relevant importance -- you can also upgrade from version 1.0.0, but see Installing OxygenOS 1.0 on the OnePlus One Smartphone and…

Performance Comparison C vs. Lua vs. LuaJIT vs. Java

, 4 min read

Ico Doornekamp on 20-Dec-2011 asked why a C version of a Lua program ran more slowly than the Lua program. The mentioned discrepancy cannot be reproduced, neither on an AMD FX-8120, nor an Intel i5-4250U processor. Generally a C version program is expected to be faster than a Lua program. Here is…

Slides on OpenMP by Christian Terboven & Dirk Schmidl

, 1 min read

Christian Terboven and Dirk Schmidl from IT Center RWTH Aachen presented a deck of slides on OpenMP: Introduction to OpenMP OpenMP Tasking In Depth OpenMP Recap OpenMP and Performance Advanced OpenMP Features Some very striking slides are reproduced here. Not directly related to OpenMP but…

Performance Comparison of mmap() versus read() versus fread()

, 8 min read

I recently read in Computers are fast! by Julia Evans about a comparison between fread() and mmap() suggesting that both calls deliver roughly the same performance. Unfortunately the codes mentioned there and referenced in bytesum.c for fread() and bytesum_mmap.c for mmap() do not really compare…

Statistics of this Blog: Crossed 30.000 Views

, 1 min read

This blog was viewed more than 30.000 times. As in this post, here are the numbers: The averages per day are: The development of visits is as below: Top posts (all time) are: Most visits come from US and Germany by a wide margin:

2015 in review – report generated by WordPress

, 1 min read

See the fireworks Elmar Klausmeier's Weblog created by blogging on WordPress.com. Check out their 2015 annual report. Here is an excerpt: The concert hall at the Sydney Opera House holds 2,700 people. This blog was viewed about 14,000 times in 2015. If it were a concert at Sydney Opera House, it…



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