kworker using cpu on an otherwise idle system

I have an old thin client that I upgraded to a home server by adding some additional RAM and storage. I noticed after a recent kernel upgrade that the system seemed sluggish at times, despite doing nothing in particular at the time. top showed that a kworker process was using CPU, not all of it, but perhaps 25 to 50% of the total CPU.

I did a lot of searching to try and track down the offender. I used tools such as perf and iotop, read about various tunables under /proc related to power management. Finally, I ran Intel’s powertop command. It showed that “Audio codec alsa…” was hammering on some event loop.

I looked at the loaded kernel modules, and on a whim, I did sudo rmmod snd_hda_intel and that fixed the issue for me.

Others may find that a kworker is running in a tight loop for some other reason. It could be some other misbehaving driver or an I/O problem.

Keep getting logged out from Selfoss on Debian

I’m running Selfoss RSS reader and loving it!

One thing I don’t love is that it logs me out frequently (BTW, I’m running Apache php-fpm on Debian Jessie). But I think I found a solution. Try adding this to a file called .user.ini in the document root of Selfoss:

The 604800 means one week. If you’re running mod_php rather than FPM, you can add these lines to your .htaccess file.

UPDATE: The format for .user.ini is not the same used in .htaccess. The .user.ini version looks like this:

Use whatever cache_limiter() setting suits your needs best.

Moving Evernote notes into WordPress

proprietary insecurity

I’ve accumulated many notes (2000+) in Evernote over the years, and love that it can store binary attachments such as images or other media files. My favorite feature is the Evernote Web Clipper browser extension; it does a fantastic job at saving the parts of an article I want to save while keeping the styling intact.

Evernote has a free plan which I’ve enjoyed for a long time, but recently the financial status of the company has come into question, and they restricted syncing to only two devices. Also, the last thing I want to happen is another kind of Google Reader shutdown fiasco. I doubt that a shutdown would make my existing notes disappear, but it’s better to be prepared ahead of time. To that extent, I’ve been looking for a viable option to migrate my notes into another platform. Continue reading “Moving Evernote notes into WordPress”

Unison dependency hell

UnisonI would really like to rid myself of Dropbox, but all the alternatives I’ve tried are too bloated, beta- or alpha-quality stage, too complicated to set up, or just plain don’t do what Dropbox does (minus the sharing stuff, which I don’t care about). I don’t want btsync, it’s closed-source. Seafile is too complicated, and makes dubious security claims. Owncloud is a cool project, but their file sync is slow, error prone, and has other limitations. There are some good services, but they don’t run on all the platforms I need, including Mac OSX, Linux x86 (32 and 64-bit), Linux ARMv6 (my Raspberry Pi B) and Android. I ran Syncthing for a while, but the continuous memory usage is pretty steep for the Pi, and I’ve experienced random silent file truncation in my shared directories with it. So I needed something else. Continue reading “Unison dependency hell”

Self-hosted open source RSS readers

I think I’ve tried pretty much all of them. After the Google Reader-pocalypse, one of the primary requirements was that I could host it myself. Bonus points go to apps that have configurable keyboard navigation (“j” to open the next item must be distinct from “space” to just scroll down in the browser), as well as decent integration on mobile. Here’s a roundup of the ones I’ve tried.

Newsblur

Awesome platform, but way too big for someone looking to host their own personal solution. I tried upgrading it once and broke it. No idea what I did wrong or how to even figure out how why it wasn’t working. Seems very well designed for a massive multi-user operation, though, if you’ve got the Python chops to figure everything out. Newsblur website.

Commafeed

Commafeed is also a larger piece of software, but requires many fewer components than Newsblur. You need Java, some java tools like maven, a DB and of course more than a little bit of RAM.

TT-RSS (Tiny Tiny RSS)

Nice, but not as configurable as I’d like. This and the rest of the readers listed are written in PHP. There are three larger downsides to tt-rss:

  • I had quite a bit of trouble trying to get it to run from a subdirectory on Nginx. This is not necessarily specific to tt-rss, many apps are hard to config this way.
  • The primary developer is not friendly. He seems to take pleasure in ridiculing people in the support forums.
  • Although it’s supposed to be tiny, and the application part is, it requires Postgres or MySQL with InnoDB support. I would prefer something that uses less memory on the DB side, either MyISAM tables or better yet SQLite.

SelfOSS

I ran SelfOSS for a while and liked it. However, I didn’t like the Android experience (what, no swipe?) so I went looking for something else.

FreshRSS

I’m currently running FreshRSS and it’s really, really good. But I’m starting to get discouraged by a few nagging bugs and the lack of recent updates to the github repo.

Miniflux

I ran Miniflux for a short time a while back and my memory is a bit hazy on the experience (after a while RSS reader experiences tend to blend in with one another). I think I’m going to give it another shot. On his site, reading down the list of what Miniflux is not vs what it is makes me take heart. The developer is clearly trying to convey a no-BS attitude with his intentions for this app. One thing that gives me a spark of hope is that there was a new point release this month. I will update this post with any news with Miniflux.

I have high hopes for wallabag

I would really like to replace Evernote with a self-hosted solution. Wallabag is one alternative that’s pretty attractive. It’s open source, supports imports and exports, and nice on the eyes.

What’s currently holding me back is the lack of an Evernote importer (I kind of expect that, and am eagerly looking forward to writing an XSLT to make that importable ;-) and the lack of features in the browser extension. Basically, Evernote’s web clipper kicks ass, so I’d really like to keep the selection tools.