Wednesday, 22 September 2010

I like driving in my car. It is not quite a Jaguar

I work from home, this is a good thing. I benefit from a 20 metre commute, comfortable working environment and generally low carbon lifestyle.

Except on Wednesdays, on Wednesday I have to get up early and go to the office, this is not usually too much of a chore and takes around 90 minutes each way.

Today was different, I made a small five minute diversion to collect a colleague to whom I was giving a lift and then due to a little problem near the M6/M61 junction spent a fun filled three hours sitting in traffic crawling along the M56. At least I had company instead of being on my own.

Before I did the return journey I decided to check the traffic news sites. Oh dear now the M60 was stuffed, I altered the route and only had to queue on the M56 for twenty minutes or so. I dropped my colleague off at his place (avoiding the worst bits of the M62/M66 junctions by use of a rather convoluted back route) and proceeded to queue on the M62 for a while for no apparent reason.

Basically I have spent almost seven hours in the car today to do a 150 miles or a little over 20 miles per hour average. I was just going to rant about the dreadful lack of any redundancy or resilience in the UK road system which often grinds to a complete and utter halt if there is a single failure.

However a different thought has wandered across my travel weary mind. It has occurred to me that this average speed is faster than anyone could reasonably expect to do this trip for the majority of human existence.

In 1810 and indeed for all time before, your best possible speed by good horse, for 150 miles, would have been two days (and your horse would have probably been very poorly afterwards) This assumes your horse could do the 75miles (120km) each way in times consistent with modern world endurance trials... across a mountain range! Yes the Pennines are only tiny but even so!

A hundred years later, in 1910, the British railway network was nearing its zenith in most measurable terms. The influence across the north of England was profound and pushed the industrial revolution ever faster towards its climax before the first world war. Even at this point in time my best reading of the available timetables says I would have needed to change trains four times each way, purchased eight separate tickets from six different companies and taken around nine hours to make the journey allowing for hanging around on platforms.

Another fifty years on, in 1960, the trans-pennine car journey would have been on poorly maintained trunk routes through the decaying cores of the declining post-industrial northern cities. The route would probably have involved the A646, A59 or the A58 which at this time were not the well maintained (if slightly shabby) roads of today but instead were dangerous twisty and, from the looks of the archive photographs, positively heaving with traffic. On these pre-motorway strips of tarmac the 150 mile round trip would have taken in excess of seven hours (even today's mapping systems suggest over four and a half hours would be needed)

So instead of being frustrated that my commute took an extended period today I have instead decided that I shall enjoy the fact it was faster and certainly more comfortable than at any time in the past. Well that and I need to get the cars air-conditioning fixed ;-)

Thursday, 16 September 2010

The turmoil of an entropy key release.

Last week we released 1.1.3 of the Entropy Key software. Poor Daniel struggled for days to get this out the door but finally he managed to build all the various debs, rpms and tars for the supported platforms and Rob got it all uploaded and announced.

The release is kinda strange in that it was the first in which the main changes were for performance. OK there is an improvement to resilience in the face of failed re-keying which some users were seeing in high load situations, but that high load was (in some cases) being caused by the daemon itself.

The process was mainly driven by one of our users, Nix, who was experiencing ekeyd using "too much" CPU on his system.

Of course on our servers during testing ekeyd it had used around a percent of CPU, certainly nothing that flagged as a problem in our own use (yes we eat our own dogfood ;-) Alas for this user on a 500MHz geode it was guzzling down 10% of his CPU which was clearly unacceptable.

This user however instead of guessing what the problem might be or simply leaving it up to us did something about it. He instrumented ekeyd, located the garbage collector tuning parameters as being incorrectly set and supplied a patch. Did he stop there? no! he then went on to profile the code further and clean up the hotspots. This resulted in ekeyd falling to less than 1% of the runtime of his system.

By reducing the CPU usage of ekeyd to this level it became more apparent where a previously reported bug was coming from, which enabled me to address it.

I know sometimes I complain about Open Source software but at times like this it makes me happy that we released the ekeyd software freely. This is how its supposed to be! Everyone working to make better software and benefiting together.

It has not just been on this occasion either, throughout the last year since our very first 1.0 release there has been helpful and useful feedback, patches from several users and even the odd thankyou mail. This project then has been a positive Open Source experience and I look forward to another constructive year maintaining this software.

Thursday, 2 September 2010

You shall go to the ball!

Contrary to my last post I was able to attend the Debian UK BBQ at the weekend. My wonderful wife ditched me at Portsmouth station with permission to go play with my friends ;-)

Perhaps a bit more explanation is warranted about that last statement! We travelled back from France last Saturday. We were on the 12:15 (CET) ferry so had to be awake and on the road for the five hour France drive at "oh my gosh its early" time. The crossing to Portsmouth was slow as it was very choppy and we were leaving the Port at 15:30 at which point Melodie was good enough to let me go play with my friends while she drove home.

I did have the "fun" of doing the Portsmouth->London->Cambridge trip on UK public transport but it went pretty smoothly. Walking from Cambridge station to the BBQ location was a bit dumb, next time I am taking a cab!

The BBQ was excellent fun and big thanks for Steve for holding it again. Its always fun to meet the usual suspects. We also got to set a new occupancy record at Steves house Saturday night and discovered that certain members of Debian UK snore rather loudly (I think at one point we could measure it on the Richter scale).

Back home now of course. Work is the same as when I left so no change there and the Boys first day back at school seems to have gone smoothly too.