On my way to Munich

Today, I’m flying to Munich for new hire orientation.

Mobile computing

I’m typing this from a bus stop over 4G. Mobility is more advanced than before. The only wire in my mobility right now is to have to use an external disk drive to store VMs:


Obviously, in this configuration, building kernels takes its toll on the battery. Don’t expect to run 10 hours like this šŸ™‚ But it is functional.

If you think back about what computing was in, say, 2000, this is really a dream come true. Several fully functional operating systems running on the same machine, each of them rather solid, taking full advantage of multitasking, etc. Comfortable keyboard, Retina display (a bit too glossy for my taste, but certainly not bad), wi-fi on the go. What’s not to like?

Sophia Antipolis public transportation is quite good

The bus to the airport costs only 1.5ā‚¬Ā andĀ is very comfortable. Sometimes, you are happy to pay taxes. I am sitting in the front row on the second floor, and I have a unique high-rise view on Sophia Antipolis from high up.

Image JPEG-4DFEC833945B-1 2.jpegThere’s Wi-Fi and even USB charging ports. Which is good, because apparently I forgot to charge my phone last night.

Renovated Airport Terminal 1

I had not been at Nice Airport Terminal 1 in quite a while. It’s been completely redone, with a nice seating area.

Image JPEG-EC370DE37028-1.jpeg

There is a small restaurant where I’ll probably eat something, given that my flight is at 1PM.

Image JPEG-B0D6C0C75EAE-1.jpeg

There is a Fnac mini, that sells iPad mini but no Mac mini.

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It was funny to hear the two employees debate whether it was the smallest in France or the smallest in the world. Given that Fnac is very much French, I don’t think it makes much of a difference.

Tip to airport designers: electrical outlets are notĀ a luxury

The one really bad thing about the renovated Terminal 1: there are no electrical outlets anywhere near the seating areas.

Well, after nearly running out of battery after a couple of hours of kernel building, I finally found one lone isolated electrical socket, located at the very end of area B (look for Franks Hot Dogs, along one of the exterior walls). It’s right next to the smoking area, which means that you can charge your laptop and die of lung cancer at the same time.

After careful investigation, there’s another set of 4 (yes, four, as in theĀ Fantastic Four) sockets located next to the restrooms. There are no real seats there, but someone helpfully brought a few wooden chairs. Well, I take the real chair and the smoke over the wooden chair and the toilet traffic. It’s all about choice.

Clearly, the airport designers thought nobody would ever need to charge a laptop while waiting for their flight. Nobody cares for bisecting kernel buildersĀ these days, what a shame šŸ˜¦ But then, the Nice airport has an issue with electricity anyways.

Kernel bisecting

9439b3710df688d853eb6cb4851256f2c92b1797: Bad
628d1655: Good. 9 steps to go. VMware copy to host stopped working, so typed by hand.
0d5320fc: Good. 8 steps to go.
2601a15d5d9b7f262e94b88784b1e1cf28ec020d: Bad
8e57ec613: Good
bfd5be0f9e0cd: Good
db444e1344dd: Bad
ad1231080be5a5cb: Good
8f5040e421ca4bbd:Bad, but interestingly, no DRM message, although GG is there
1f32478f: Bad

The bad commit isĀ dabdcdc9822ae4e23cd7ff07090098d34f287b28, “drm/vmwgfx: Switch to mode_cmd2”. Unsurprisingly, it seems to affect VMware graphics (vmwgfx).

In addition to the copy-paste bug, there is also a serial-port bug, where the serial port sometimes stops working, is put in a disconnected state, and you have to be careful about reconnecting it before “it’s too late” and your messages are gone.

Apparently, I was really overloading my machine by having too many VMs running, and VMware is taking a high toll in that case. With only one VM running, building a kernel is only 2 minutes now (15 minutes real).

OK, I was wrong. This really depends on the bisect I do. I’m surprised a large bisect step like the one I just did could rebuild so incrementally. But apparently, I was lucky. The next one is taking much longer. It’s funny that the one time I time-d the build, it was much faster than usual. I guess kernel build makefiles are self-aware now, and they try to look good when they know someone is looking :-).

What is really taking some time now is when the shutdown waits for “stop jobs”. Like, right now, for the NFS mount to my servers, which I no longer see, since I’m in the bus. I could VPN into my hope, but that’s of dubious value. Much faster to brute-force restart the VM :-D.

Mounting and unmounting NFS shares takes time

Interesting that on reboot, it tries to mount my server, but I remember notĀ seeing the NFS mount and having to mount -a manually. Timeout maybe?

Where to file kernel bugs underĀ virtualization?

I filed the bug I found under virtualization in Bugzilla. And then there was a component named lguest, which I took to mean Linux guest. It’s not. It’s a hypervisor I did not know about. There’s a testimonial on the web site that tells me it might be interesting for me:

I suggest you try this yourself – lguest is incredibly easy to get up and running. It’s also quite useful: I can test-boot kernels with it in less than a second, or about 10x faster than basic qemu, and 100x faster than a real boot. And as it uses a pty as console, you can do things like pipe it through grep.

ā€”Ā Matt Mackall on linux-kernel

But then, I don’t know if there is a good way to indicate “Linux as a guest in VMware” in Bugzilla (except in the Bugzilla itself).

DevConf.cz schedule posted

The schedule for DevConf.cz has been posted.

Apple Watch: More useful than I thought

My flight is delayed by 30 minutes. I got the notification on the Apple Watch. For that, a smart watch is really useful. It takes much less time to glance at a message than picking up the smartphone in your pocket.

I also became quite fond of the “Unlock with Apple Watch” feature, where I don’t need to type a password if I wear the Apple Watch and it’s unlocked. It’s really quite handy when you carry stuff (say, hard disks or coffee, two staples of software engineering).

The magic of keyboard shortcuts

I hit some keys while Thunderbird was open. Now I find myself with things marked junk, others that have personal or later tags. That means there are really useful features there, I need to read the documentation.

Typing stuff at random: I call this the monkey school ofĀ training.

So 15 set or clear tags, and 0 removes all of them. Really useful. K ignores a thread. S marks a message with a little star. Is Thunderbird slowly converting me?



Author: Christophe de Dinechin

I try to change the world, but that's work in progress. If you want to know me, google "Christophe de Dinechin". Keywords: concept programming, virtualization, OS design, programming languages, video games, 3D, modern physics. Some stuff I did that I'm proud of: the first "true" 3D game for the PC, HP's big iron virtualization, real-time test systems for car electronics, some of the best games for the HP48 calculator, a theory of physics that makes sense (at least to me).

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