Older blog entries for bagder (starting at number 801)

My FOSDEM 2014

I’m back home after FOSDEM 2014.Lots of coffee A big THANK YOU from me to the organizers of this fine and totally free happening.

Europe’s (the World’s?) biggest open source conference felt even bigger and more crowded this year. There seemed to be more talks that got full, longer lines for food and a worse parking situation.

Nothing of that caused any major concern for me though. I had a great weekend and I met up with a whole busload of friends from all over. Many of them I only meet at FOSDEM. This year I had some additional bonuses by for example meeting up with long-term committers Steve and Dan from the curl project whom I had never met before IRL. Old buddies from Haxx and Rockbox are kind of default! :-)

Talk-wise this year was also extra good. I’ve always had a soft spot for the Embedded room but this year there was fierce competition for my attention so I spread my time among many rooms and got to see stuff about: clang the compiler, lots of really cool stuff on GDB, valgrind and helgrind, power efficient software, using the GPU to accelerate libreoffice, car automation and open source, how to run Android on low-memory devices, Firefox on Android and more.

I missed out the kdbus talks since it took place in one of them smaller devrooms even though it was “celebrity warning” all over it with Lennart Poettering. In general there’s sometimes this problem at FOSDEM that devrooms have very varying degrees of popularity on the different talks so the size of the room may be too large or too small depending on the separate topics and speakers. But yeah, I understand it is a very hard problem to improve for the organizers.

As a newbie Firefox developer at Mozilla I find it fun to first hear the Firefox on Android talk for an overview on how things  run on that platform now and then I also got references to Firefox both in the helgrind talk and the low-memory Android talk. In both negative and positive senses.

As always on FOSDEM some talks are not super good and we get unprepared speakers who talks silently, monotone and uninspired but then there’s the awesome people that in spite of accents and the problem of speaking in English as your non-native language can deliver inspiring and enticing talks that make me just want to immediately run home and try out new things.

The picture on the right is a small tribute to the drinks we could consume to get our spirits up during a talk we perhaps didn’t find the most interesting…

This year I found the helgrind and the gdb-valgrind talks to be especially good together with Meeks’ talk on using the GPU for libreoffice. We generally found that the wifi setup was better than ever before and worked basically all the time.

Accordingly, there were 8333 unique MAC addresses used on the network through the two days, which we then can use to guesstimate the number of attendees. Quite possibly upwards 6000…

See you at FOSDEM 2015. I think I’ll set myself up to talk about something then. I didn’t do any this year.

Syndicated 2014-02-03 08:34:07 from daniel.haxx.se

HTTP2 – the next step

IETFThe HTTPbis working group of the IETF had an interim meeting in Zurich January 22nd to 24th. I participated from remote and I listened in on the discussions over webex and followed the jabber room while the meetings were going on, addressing HTTP2 protocol issues one by one ironing out quirks and progressing forward.

I won’t bore you with details why I wasn’t present in Zurich.

Here’s a couple of quick and brief reflections from my perspective:

Listening in from remote like this is not at all adequately compensating for not being there. A room full of people discussing something is really hard to follow from remote and completely impossible to interact with. It is better than not being able to listen in at all, but it is certainly not a replacement for being there.

It is amazing how much faster people can come to conclusions and fix issues when being in the same room. Issues that have been lingering in the tracker for a very long time could be dealt with and closed within minutes. Things like what to call the protocol in ALPN or to remove the ability to switched off flow control. Not all issues of course…

HTTP2 draft-09 that soon will become draft-10 to reflect the updates from this meeting and more, is from my perspective quite far in its process. It is clearly at a point that seems to be OK with most people and the discussions are now just about details. Of course the devil is in the details and I’m not saying it can’t take a long time to settle on them, but the structure and main concepts of the protocol are probably now established.

There were not very many proxy or server people at the interim. Most of the people seemed to be client-side oriented and some service oriented. I’m personally client-side biased myself but I hope this doesn’t lead to us deciding on things that the “other side” will have problems with down the line.

Firefox nightly supports HTTP2 draft-09 (for https:// URLs) and twitter supports it server side. Enable it in the browser by entering “about:config” in the URL bar and change the config entry called “network.http.spdy.enabled.http2draft” to true. Done.

Some of the biggest HTTP2 changes brought up compared to what draft-09 says include:

  • no more ability to switch off flow control
  • the prioritization field/concept “weighted dependency tree approach”
  • >= TLS 1.2 with ephemeral ciphers
  • MUST not use TLS compression
  • tolerant to TLS false start or at least must accept/buffer application layer data
  • padding

There was also a whole lot of discussions about TLS for http:// urls, proxys, MITM for SSL, opportunistic encryption and more but I believe most of those issues remained at the same position as before – I missed out on parts of the last afternoon so I may have missed some details. It’ll all be revealed in draft-10 and the mailing list I’m sure!


Syndicated 2014-01-24 21:40:08 from daniel.haxx.se

My first Mozilla week

Working from home

I get up in the morning, shave, eat breakfast and make sure all family members get off as they should. Most days I walk my son to school (some 800 meters) and then back again. When they’re all gone, the house is quiet and then me and my cup of coffee go upstairs and my work day begins.

Systems and accounts

I have spent time this week to setup accounts and sign up for various lists and services. Created profiles, uploaded pictures, confirmed passwords. I’ve submitted stuff and I’ve signed things. There’s quite a lot of systems in use.

My colleagues

I’ve met a few. The Necko team isn’t very big but the entire company is huge and there are just so many people and names. I haven’t yet had any pressing reason to meet a lot of people nor learn a lot of names. I feel like I’m starting out this really slowly and gradually.

Code base

Firefox is a large chunk of code. It takes some 20 minutes to rebuild on my 3.5GHz quad-core Core-i7 with SSD. I try to pull code and rebuild every morning now so that I can dogfood and live on the edge. I also have a bunch of local patches now, some of them which I want to have stewing in my own browser for a while so that I know they at least don’t have any major negative impact!

Figuring out the threading, XPCOM, the JavaScript stuff and everything is a massive task. I really cannot claim to have done more than just scratched the surface so far, but at least I am scratching and I’ve “etagged” the whole lot and I’ve spent some time reading and reviewing code. Attaching a gdb to a running Firefox and checking out behavior and how it looks has also helped.

Netwerk code size

“Netwerk” is the directory name of the source tree where most of the network code is located. It is actually not so ridiculously large as one could fear. Counting only C++ and header files, it sums up to about 220K lines of code. Of course not everything interesting is in this tree, but still. Not mindbogglingly large.

Video conferencing

I’ll admit I’ve not participated in this sort of large scale video conferences before this. Wiith Vidyo and all the different people and offices signed up at once – it is a quite impressive setup actually. My only annoyance so far is that I didn’t get the sound for Vidyo to work for me in Linux with my headphones. The other end could hear me but I couldn’t hear them! I had to defer to using Vidyo on a windows laptop instead.

Doing the video conferencing on a laptop instead of on my desktop machine has its advantages when I do them during the evenings when the rest of the family is at home since then I can move my machine somewhere and sit down somewhere where they won’t disturb me and I won’t disturb them.


The bug tracker is really in the center for this project, or at least for how I view it and work with it right now. During my first week I’ve so far filed two bug reports and I’ve submitted a suggested patch for a third bug. One of my bugs (Bug 959100 – ParseChunkRemaining doesn’t detect chunk size overflow) has been reviewed fine and is now hopefully about to be committed.

I’ve requested commit access (#961018) as a “level 1″ and I’ve signed the committer’s agreement. Level 1 is entry level and only lets me push to the Try server but still, I fully accept that there’s a process to follow and I’m in no hurry. I’ll get to level 3 soon enough I’m sure.


What can I say. After having used it a bit this week without any particularly fancy operations, I prefer git so much more. Of course I’m also much more used to git, but I find that for a lot of the stuff where both have similar concepts I prefer to git way. Oh well, its just a tool. I’ll get around. Possibly I’ll try out the git mirror soon and see if that provides a more convenient environment for me.


What impact did all this new protocol and network code stuff during my work days have on my curl activities?

I got inspired to fix both the chunked encoding parser and the cookie parser’s handling of max-age in libcurl.

What didn’t happen

I feel behind in the implementing-http2 department. I didn’t get my new work laptop yet.

Next weekDaniel's work place

More of the same, land more patches and figure out more code. Grab more smallish bugs others have filed and work on fixing them as more practice.

Also, there’s a HTTPbis meeting in Zürich on Wednesday to Friday that I won’t go to (I’ll spare you the explanation why) but I’ll try to participate remotely.

Syndicated 2014-01-17 15:34:53 from daniel.haxx.se

My commute

Just in case you missed my youtube/G+ posting from yesterday about my new trip to work:

Syndicated 2013-11-27 18:56:07 from daniel.haxx.se

Parallel Spaghetti Decode Challenge

At the embedded hacking event in GBG yesterday I organized a small contest for the attendees. I’ve done something similar several times before, so I wanted to make it a bit different this time to spice things up a bit. A straight-forward N questions in a row and then a puzzle to get the final question was too easy. I wanted to create a maze or a play-field that you would need to traverse somehow in order to reach the final goal. But it is hard to create a maze that you don’t immediately spot the way through or that you can somehow “cheat” and find the way in other means rather than to actually answer the questions and do right by using your skills… Then I realized that with just a couple of things added, I could fulfill my goals and still get a fun contest. So, let me start by taking you through the first slide that details the rules:

The contest rules

Ok, so to make the rules be a bit clearer we take a look at a simplified example play field so that we understand what we’re about to play on:

A small example play-field

A short summary:

  1. start on a green box
  2. follow the arrow in the direction that your answer to the question of the box leads you. There’s a compass rose there to help you remember the directions! :-)
  3. each box you visit has a word associated with it, collect the words along the path
  4. when you reach the red box you’ve read the goal and you’re done
  5. then you re-arrange all the box words you’ve collected and create a final question
  6. answer that questions, the fastest to answer wins!

Everything clear? To help the participants, we had both the playfield and the associated questions printed out on two sheets of paper that we handed out together with a pen. The amount of data is just a bit too much to be able to show on a single screen and it may help to use a pen etc to remember the track you take and which words to remember etc. If you want to repeat the exact same situation, you do the same! I did a special black-and-white version of the playfield to make it more printer-friendly. You may want to fire this up in full resolution to get the best experience:


The question sheet looks like this, but click it for the full PDF:

All questions for the challenge

I posted the answers and everything in a separate post!

Syndicated 2013-11-22 19:47:08 from daniel.haxx.se

Rpi night in GBG

pelagicore logo

Daniel talking So I flew down to and participated at yet another embedded Linux hacking event that was also co-organized by me, that took place yesterday (November 20th 2013) in Gothenburg Sweden.

The event was hosted by Pelagicore in their nice downtown facilities and it was fully signed up with some 28 attendees.

I held a talk about the current situation of real-time and low latency in the Linux kernel, a variation of a talk I’ve done before and even if I have modified it since before you can still get the gist of it on this old slideshare upload. As you can see on the photo I can do hand-wavy gestures while talking! When I finally shut up, we were fed tasty sandwiches and there was some time to socialize and actually hack on some stuff.

Embedded Linux hackers in GBG

I then continued my tradition and held a contest. This time I did raise the complexity level a bit as I decided I wanted a game with more challenges and something that feels less like a quiz and more like a game or a maze. See my separate post for full details and for your chance to test your skills.

This event was also nicely synced in time with the recent introduction of the foss-gbg mailing list, which is an effort to gather people in the area that have an interest in Free and Open Source Software. Much in the same way foss-sthlm was made a couple of years ago.

Pelagicore also handed out 9 Raspberry Pis at the event to lucky attendees.

Syndicated 2013-11-21 17:21:59 from daniel.haxx.se

792 older entries...

New Advogato Features

New HTML Parser: The long-awaited libxml2 based HTML parser code is live. It needs further work but already handles most markup better than the original parser.

Keep up with the latest Advogato features by reading the Advogato status blog.

If you're a C programmer with some spare time, take a look at the mod_virgule project page and help us with one of the tasks on the ToDo list!