, 1 min read
I wrote on SLURM used on Ubuntu here. As I moved to Arch Linux I of course use the fine AUR package slurm-llnl maintained by Gordian Edenhofer. After upgrading to version 16.05.7-1 I noticed the following: If slurmd is started by systemd then the pid-file specified for systemd in…
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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…
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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…
, 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…
, 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…
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Here is a photo when the Dell XPS-13 is opened: And here is the Acer Aspire opened:
, 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…
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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…
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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.…
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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…
, 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…
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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…
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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…
, 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…
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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…
, 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…
, 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…
, 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…
, 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…
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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: