Older blog entries for timj (starting at number 14)

Attending LinuxTag 2011

 

Like every year, I am driving to Berlin this week to attend LinuxTag 2011 to attend the excellent program. If you want to meet up and chat about projects, technologies, Free Software or other things, send me an email or leave a comment with this post and we will arrange for it.

Syndicated 2011-05-09 12:29:55 from Tim Janik

BEAST v0.7.4 released

BEAST/BSE version 0.7.4 is available for download at:

BEAST is a music composition and modular synthesis application released as free software under the GNU LGPL that runs under Unix. Refer to the About page for more details.

The 0.7.4 release integrates the bse-alsa package, several speedups, important bug fixes and translation updates.

Please feel free to provide useful feedback or contribute on IRC, the mailing list and in the Wiki.

TRANSLATORS: Please help us to improve the BEAST translation, just download the tarball, edit po/.po and email it to us or submit translations directly via the Beast page at Transifex.

Overview of Changes in BEAST/BSE 0.7.4:

  • Renamed the project to Better Audio System / Better Sound Engine
  • Moved project website to: http://beast.testbit.eu/
  • Various build system fixes [stw,timj]
  • License fixups for some scripts [stw]
  • Fixed subnormal tests on AMD64 if SSE unit is in DAZ mode [stw]
  • Replaced slow resampler checks with a much faster resampling test [stw]
  • Performance improvements for various tests [stw]
  • GLib 2.28 unit test porting [stw]
  • Speed improvements for record field name [stw]
  • Fixed XRUNs in ALSA driver on 64bit systems [timj]
  • Added beast.doap [Jonh Wendell]
  • PO handling improvements.
  • Updated German translation.
  • Updated Norwegian bokmål translation [Kjartan Maraas]
  • Added e-Telugu translation [Veeven]

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Syndicated 2011-04-09 01:50:16 from Tim Janik

Human Multitasking

Multitasking Mind
(Image: Salvatore Vuono)

 

The self deceiving assumption of effective human multitasking.

 

People are often telling me they are good at multitasking, i.e. handling multiple things at once and performing well at doing so. Now, the human brain can only make a single conscious decision at a time. To understand this, we need to consider that making a conscious decision requires attention, and the very concept of attention means activating relevant information contexts for an observation or decision making and inhibiting other irrelevant information.

The suppression involved in attention control makes it harder for us to continue with a previously executed task, this is why interruptions affect our work flows badly, such as an incoming call, SMS or a door bell. Even just making a decision on whether to take a call already requires attention diversion.

Related, processing emails or surfing while talking to someone on the phone results in bad performance on both tasks, because the attention required for each, necessarily suppresses resources needed by the second task. Now some actions don’t suffer from this competition, we can walk and breathe or balance ourselves fine while paying full attention to a conversation. That’s because we have learned early on in our lives to automate these seemingly mundane tasks, so they don’t require our conscious attention at this point.

Studies [1] [2] have shown time and again, that working on a single task in isolation yields vastly better results and in a shorter time frame when frequent context switches are avoided. This can be further optimized by training in concentration techniques, such as breath meditation, autogenic training or muscle relaxation.

Here’s a number of tips that will help to put these findings to practical use:

  1. Let go of the idea of permanent reachability, nothing is so urgent that it cannot wait the extra hour to be handled efficiently.
  2. Make up your own mind about when to process emails, SMS, IM, news, voice messages.
  3. Start growing a habit of processing things in batches, e.g. walk through a list of needed phone calls in succession, compose related replies in batches, first queue and later process multiple pending reviews at once, queue research tasks and walk through them in a separate browsing session, etc.
  4. Enforce non-availability periods where you cannot be interrupted and may concentrate on tasks of your choice for an extended period.
  5. Schedule phone meetings in advance, ensure everyone has an agenda at hand for the meeting to avoid distractions (Don’t Call Me, I Won’t Call You).
  6. Deliberately schedule relaxation phases, e.g. take a 5 minute break off the screen per hour, ideally moving and walking around; rest breaks are needed after 90 minutes at latest.

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Syndicated 2011-03-31 01:11:37 from Tim Janik

Lanedo at CeBIT 2011

This week, our people are running the Lanedo booth at CeBIT in Hannover.

CeBIT Logo

Everybody is invited to come and visit us in hall 2, booth D44/124, in the open source park. We will give introductions to our services, talk about current and future developments around GTK+ and Tracker and anything you want to approach us with.

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Syndicated 2011-02-28 20:04:15 from Tim Janik

Using mod_disk_cache with MediaWiki

 

MediaWiki is a pretty fast piece of software out of the box. It’s written in PHP and covers a lot of features, so it can’t serve pages in 0 time, but it’s reasonably well written and allows use of PHP accelerators or caches in most cases. Since it’s primarily developed for Wikipedia, it’s optimized for high performance deployments, caching support is available for Squid, Varnish and plain files.

For small scale use cases like private or intranet hosts, running MediaWiki uncached will work fine. But once it’s exposed to the Internet, regularly crawled and might receive links from other popular sites, serving only a handful of pages per second is quickly not enough. A very simple but effective measure to take in this scenario is the enabling of Apache’s mod_disk_cache.

Here’s a sample benchmark for the unoptimized case:

$ ab -kt3 http://testbit.eu/Sandbox
Time taken for tests:   3.33173 seconds
Total transferred:      301743 bytes
Requests per second:    6.26 [#/sec] (mean)
Time per request:       159.641 [ms] (mean)
Transfer rate:          96.93 [Kbytes/sec] received

Now we configure mod_disk_cache in apache2.conf:

CacheEnable   disk /
CacheRoot     /var/cache/apache2/mod_disk_cache/
And enable it in Apache:
$ a2enmod disk_cache
Enabling module disk_cache.
Run '/etc/init.d/apache2 restart' to activate new configuration!

This in itself is not enough to enable caching of MediaWiki pages however, this is due to some bits in the HTTP header information it’s sending:

$ wget -S --delete-after -nd http://testbit.eu/Sandbox
--2011-02-09 00:48:21--  http://testbit.eu/Sandbox
  HTTP/1.1 200 OK
  Date: Tue, 08 Feb 2011 23:48:21 GMT
  Vary: Accept-Encoding,Cookie
  Expires: Thu, 01 Jan 1970 00:00:00 GMT
  Cache-Control: private, must-revalidate, max-age=0
  Last-Modified: Tue, 08 Feb 2011 03:24:32 GMT
2011-02-09 00:48:21 (145 KB/s) - `Sandbox' saved [14984/14984]

The Expires: and Cache-Control: headers both prevent mod_disk_cache from caching the contents.

A small patch against MediaWiki-1.16 fixes that by removing Expires: and adding s-maxage to Cache-Control:, which allows caches to serve “stale” page versions which are only mildly outdated (a few seconds).

mw-disk-cache-201101.diff
With the patch, the headers changed as follows:
$ wget -S --delete-after -nd http://testbit.eu/Sandbox
--01:03:03--  http://testbit.eu/Sandbox
 HTTP/1.1 200 OK
 Date: Wed, 09 Feb 2011 00:03:03 GMT
 Vary: Accept-Encoding,Cookie
 Cache-Control: s-maxage=3, must-revalidate, max-age=0
 Last-Modified: Tue, 08 Feb 2011 03:24:32 GMT
01:03:03 (386.21 MB/s) - `Sandbox' saved [14984/14984]

Upon inspection, there’s no Expires: header now and Cache-Control: adapted as described. Let’s now rerun the benchmark:

$ ab -kt3 http://testbit.eu/Sandbox
Time taken for tests:   3.5511 seconds
Total transferred:      38621189 bytes
Requests per second:    831.14 [#/sec] (mean)
Time per request:       1.203 [ms] (mean)
Transfer rate:          12548.95 [Kbytes/sec] received

That looks good, 831 requests instead of 6!

Utilizing mod_disk_cache with MediaWiki can easily speed up the number of possible requests per-second by more than a factor of one hundred for anonymous accesses. The caching behavior in the above patch can also be enabled for logged-in users with adding this setting to MediaWiki’s LocalSettings.php:

$wgCacheLoggedInUsers = true;

I hope this helps people out there to speed up your MediaWiki installation as well, happy tuning! ;)

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Syndicated 2011-02-09 01:03:45 from Tim Janik

New Beast Website

Last week the Beast project went live with a new website that has been in the making since December:

beast.testbit.eu
The old website was several years old, adding or changing content was very cumbersome and bottlenecked on Stefan or me. All edits had to go into the source code repository, adding content pages meant editing web/Makefile.am and changing a menu entry required the entire site to be rebuilt and re-synced. Also beast.gtk.org went offline for several weeks due to hosting problems at UC Berkeley.
So in the last few weeks the Beast website has been gradually moved from beast.gtk.org to beast.testbit.eu and a different hosting service that has more resources available. In the last few years, I’ve gained experiences with Plone, Drupal, DokuWiki, Confluence, a beast-specific markup parser, Joomla, WordPress, etc. They all have their up and down sides, and while I prefer WordPress for my own blog, I’ve settled on MediaWiki for the new Beast website.
Running the new site entirely as a wiki makes the contents easily accessible for everyone willing to contribute and MediaWiki’s markup is what most people already know or are likely to learn in the future. MediaWiki must be the hardest tested collaborative editing tool available, turns out to be impressively feature rich compared to other Wiki engines, has a rich set of extensions, scripting facilities and due to Wikipedia weight a reliable maintenance future.
Much of the previously hand crafted code used for site generation and operation becomes obsolete with the migration, like the screenshot gallery PHP snippets. The entire build-from-source process can be eliminated, and running a dedicated Beast theme on MediaWiki allows editing of the menu structure in a wiki page.
Also MediaWiki allows running multiple front ends under different domains and with different themes on the same Wiki database, which allowed me to merge the Beast site and testbit.eu to reduce maintenance.
A small set of patches/extensions were used to tune MediaWiki for the site’s needs:
  • Enhancing the builtin search logic, so it automatically resorts to partial matches for empty result lists.
  • Adjusting Expires/Cache-Control headers to utilize mod_disk_cache – this increases the number of possible requests per-second by more than a factor of one hundred.
  • Adding support for [[local:/path/to/download/area]] URLs, to refer to downloadable files from within wiki pages.
It took a while to migrate contents gradually into MediaWiki format, as some files had to be migrated from a very old ErfurtWiki installation, some came from the source code repository and some were available in HTML only. Big Kudos to David Iberri, his online html2wiki converter (html2wiki on CPAN) has been a huge help in the process.
I hope the new site is well received, have fun with it!

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Syndicated 2011-02-05 05:05:23 from Tim Janik

Got The Time?

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Syndicated 2010-12-18 20:55:06 from Tim Janik

10.09.2010 BEAST/BSE release 0.7.2 available

BEAST/BSE and BSE-ALSA version 0.7.2 are available for download:

    http://beast.gtk.org/beast-ftp/v0.7/beast-0.7.2.tar.bz2
    http://beast.gtk.org/beast-ftp/v0.7/bse-alsa-0.7.2.tar.bz2

BEAST is a music composition and modular synthesis application. The “Bedevilled” portion of the names has no religious background, please refer to the About page for more details.

    Homepage:           http://beast.gtk.org/
    Downloads:          http://beast.gtk.org/beast-ftp/
    Feedback:           http://mail.gnome.org/mailman/listinfo/beast/

The 0.7.2 release provides new plugins and instruments, and a long list of bug fixes, improvements and translation updates.

TRANSLATORS: Please help us to improve the BEAST translations at Transifex.

Overview of Changes in BEAST/BSE 0.7.2:

  • Moved Beast/BSE to GNU LGPL, use AS-IS license for examples
  • Module changes and additions: ArtsCompressor – Relicensed to LGPL with permission from Matthias Kretz BseContribSampleAndHold – Relicensed to LGPL with permission from Artem Popov DavXTalStrings – Use deterministic random numbers for unit tests BseNoise – Improved random number generator
  • Switched to autogenerated ChangeLogs
  • Error bell can be muted in beast preferences dialog
  • Added multisample creation/editing command line tool: bsewavetool
  • Support adjustable volume, pitching and drum envelopes in .bsewave files
  • Added Retro Acoustic drum kit [Tim, Stefan]
  • New loadable Instruments/Effects:
    - BQS Bass Drum E8012 [Tim, Stefan]
    - BQS Slow Hum [Stefan, William DeVore]
    - FSM Fresh Water Bass instrument [Krzysztof Foltman]
    - FSM Growl Bass instrument [Krzysztof Foltman]
    - FSM Synth String Sweep [Krzysztof Foltman]
    
  • Added support for loading 32bit and 24bit PCM-format WAV files
  • Added support for gcc-4.4 and automake-1.10
  • Added support for guile-1.8, guile-1.6 remains as minimum requirement
  • Various fixes, improvements and much improved test coverage.
  • Bug fixes: #452604, #468229, #344388, #451086, #450724, #454121, #491552, #450490, #441936, #336766, #433431, #474332, #474244, #456879, #456408, #424897 [Tim Janik, Stefan Westerfeld]
  • Migrated translation support to use awk, sed and po/Makefile.am.
  • Updated German translation [Mario Blättermann]
  • Updated Italien translation [Michele Petrecca]
  • Updated Occitan translation [Yannig Marchegay]
  • Updated Brazilian Portugues translation [Leonardo Ferreira Fontenelle]
  • Updated British English translation [David Lodge]
  • Updated Spanish translation [Jorge Gonzalez]
  • Updated Slovenian translation [Andrej Znidarsic]
  • Updated Danish translation [Joe Hansen]
  • Updated French translation [Bruno Brouard]
  • Added Norwegian bokmal translation [Kjartan Maraas]
  • Added Ukrainian translation [Maxim V. Dziumanenko]

Overview of Changes in BSE-ALSA 0.7.2:

  • Fixes for automake-1.10 builds
  • Moved Beast/BSE to GNU LGPL

UPDATES: Updated translator instructions and uploaded a new release tarball with build fixes.

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Syndicated 2010-09-10 01:28:56 from Tim Janik

09.09.2010 Request to support voting in GNOME Bugzilla

These days I often have a hard time to keep up with the tasks on my TODO lists, but I do manage to sneak in a spare hour here or there to look into code I authored sometime ago and that’s waiting for maintenance attention. For projects like Gtk+/GLib it’s incredibly hard to figure a good start and order for bug processing if time is sparse and the number of bugs is flooding you.

Other projects on the net use issue trackers that support user voting of individual requests, here are two examples:

Of course I do realize that we have priority and severity fields in GNOME Bugzilla, but those are for a different purpose than polling the public opinion on which bugs should be fixed best/next, or which bugs have the largest pain impact on our user base.

At least for me, a publicly open voting system for GNOME Bugs would be immensely useful to judge where it’s best to concentrate my development efforts.

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Syndicated 2010-09-09 12:53:11 from Tim Janik

30.08.2010 Rapicorn release 10.08.0 available

Rapicorn 10.08.0 is available for download:

    http://rapicorn.org/dist/rapicorn/rapicorn-10.08.0.tar.bz2

Rapicorn is an Experimental UI Toolkit. Most things in a toolkit implementation will benefit from proper application of modern technologies (e.g. pthreads, XCB, Cairo, compositing, IDL, XML notation, path evaluation, DSLs, unit tests, SVG). Rapicorn is developed on this base with the aim to significantly improve developer efficiency and user experience.

This release contains a multitude of new features like Python bindings, an automated test suite, myriads of bug fixes and small improvements.

    Homepage:           http://rapicorn.org/
    Downloads:          http://rapicorn.org/dist/rapicorn/
    Feedback:           http://rapicorn.org/mailman/listinfo/rapicorn-list

Updates in Rapicorn 10.08.0:

  • Introduced Cairo dependency.
  • Introduced C++ TR1 dependency (for shared_ptr, etc).
  • Added $RAPICORN environment variable to control logging and more.
  • Added PLIC, a pluggable IDL compiler.
  • Added Remote Object Programming Extension.
  • Added window and widget addressing functionality.
  • Allow signal disconnections by Id.
  • Added simple expression parser to evaluate property value assignments.
  • Added sample expression evaluator as: ui/tests/sinfextest –shell
  • Added XML UI file error reporting.
  • Changed packing properties into regular Item properties.
  • Merged h/v-scale and -align into Item pack properties.
  • Replaced hfill/vfill in Table by h/v-scale and -align properties.
  • Replaced *_attach in table by Item’s h/v-position and -span properties.
  • Got rid of the packer class entirely.
  • Added testing framework with macros and reference files.
  • Added ‘-x’ to rapidrun to auto-exit.
  • Added ‘–list’ to rapidrun to list gadgets from a GUI file.
  • Provide regular expression parser API in rapicorn-core.
  • Introduced a basic typed value system and model APIs.
  • Started list area/widget development.
  • Optimized resizing performance.
  • Cosmetic fixups in colors and gradients.
  • Implemented horizontal and vertical size groups.
  • Renamed string_to_cescape() and fixed string_to_cquote() quoting.
  • Generate internal C++ bindings (to IDL specifications).
  • Provide a main loop implementation in Python.
  • Generate external Python bindings.
  • Majorly extended test suite.
  • Optimized remote invocations and reference counting.
  • Started migrating interfaces from headers to IDL.
  • Hand optimized threading primitives and main loop handling.
  • Applied fixes for AMD64 compilation. [Stefan Westerfeld]
  • Updates to compile with GCC-4.4.
  • Linker optimizations to improve ELF relocations.
  • Loads of other cleanups and bug fixes.

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Syndicated 2010-08-20 21:57:50 from Tim Janik

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