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Showing posts from September, 2011

This Blog Has Moved!

Right, so yes, five years ago I moved to github pages, and never bothered to redirect any of these pages there. Now I've moved on from there, and... Finally I am using my real domain, trishagee.com . My blog is now at trishagee.com/blog .  See you there!
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JavaOne 2011

So, I'm off to JavaOne next week! This is an unexpected and very pleasant surprise.  I'll be there with Martin (of the Disruptor fame), and Martijn (that's not going to get confusing at all).  Martin will be talking about the Disruptor on Thursday, and Martijn is busy talking about... everything.  Most importantly for the LJC he's representing us in our shiny new JCP Executive Committee role. I'm really looking forward to meeting pretty much anyone and everyone who'll talk to me.  It's the first international conference I've been to and I'm hoping to meet people I wouldn't normally get a chance to see in London.  It's also really cool to be able to represent both LMAX and the London Java Community. Hopefully it won't lead to some sort of split personality syndrome. Almost more excitingly, I'll be doing a spot of shopping in New York on the way there and back. Because, well, it would be rude to fly over to the States and n
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First public appearance caught on video

Remember a while back I talked about my first public appearance ? Well, I chased down the video, because I'm masochistic, and here it is for you all to enjoy.  Pleasingly my mannerisms are slightly less of a camp man trapped in a woman's body, which was my impression the last time I saw myself presenting.  It helps that YouTube has made the video so dark you can't see me. Slides are available for all to enjoy . Special thanks to Playfish for hosting the event - as always, their hospitality was awesome.  The fact that they didn't serve wine is probably a Good Thing.
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Are you an awesome developer?

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We are hiring ! If you think we're doing something interesting , or if you think you can help us do our thing even better , come join us.  Your boss will be the dude who wrote Continuous Delivery , you'll get a chance to experience what Danny calls meta-Agile (or Agile Agile), and you'll really start to care about Domain-Driven Design . Ideally we're after Java people, but at the heart of it we want people who are dead passionate about development. Apply via the Stack Overflow Careers advert  (you get extra brownie points if you mention my blog).
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What my hangovers can teach you about Agile

As a survival trait for living and working in the cites 1 of London, I have a set of rituals to avoid hangovers. If you are not a single person living in a city like London, you might not understand how vital this is. Most networking, particularly in the financial services industry, is done in the presence of alcohol. So preventing the inevitable hangover is quite important to the other part of the job – the actual working bit. I'll let you into a secret and tell you my nightly ritual: Floss and clean teeth (OK I'll admit, I barely floss when I'm sober let alone drunk) Cleanse/tone/moisturise (I'm a rubbish girl, this is a very recent ritual for me) Apply cuticle cream Do my calf stretches Drink 500ml of water Eat something, even if it's a dirty McDonalds (quarter pounder with cheese, no pickle no onion). Prior to all this is the additional requirement “don't drink more than a bottle and a half of wine”. Everyone has their limits, lots of practi
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Location: London W8, UK
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Effective Sketches

On Thursday I was at Simon Brown's Effective Sketches session at Skillsmatter .  Just because my pictures are pretty awesome doesn't mean there's no opportunity for continuous learning. The points Simon made in the session really made sense to me, and I wish I could have had something like that as a primer when they taught us UML at university.  Without the context of what the diagrams were supposed to mean, to convey, all the boxes and lines made no sense to me back then.  I'm still not a fan of large chunks of UML because I think the convention sometimes gets in the way of real meaning. My take-away points were: Don't try and squidge everything onto a single diagram.  The reason lots of different flavours of architecture diagrams exist (e.g. logical view , infrastructure view , etc) is because you have different audiences for each of the diagrams and different things that are important when you're looking at it from one particular angle. One diagram yo
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Popular posts from this blog

Dissecting the Disruptor: What's so special about a ring buffer?

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Recently we open sourced the LMAX Disruptor , the key to what makes our exchange so fast.  Why did we open source it?  Well, we've realised that conventional wisdom around high performance programming is... a bit wrong. We've come up with a better, faster way to share data between threads, and it would be selfish not to share it with the world.  Plus it makes us look dead clever. On the site you can download a technical article explaining what the Disruptor is and why it's so clever and fast.  I even get a writing credit on it, which is gratifying when all I really did is insert commas and re-phrase sentences I didn't understand. However I find the whole thing a bit much to digest all at once, so I'm going to explain it in smaller pieces, as suits my  NADD audience. First up - the ring buffer.  Initially I was under the impression the Disruptor was just the ring buffer.  But I've come to realise that while this data structure is at the heart of the patte
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Dissecting the Disruptor: Writing to the ring buffer

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This is the missing piece in the end-to-end view of the Disruptor.  Brace yourselves, it's quite long.  But I decided to keep it in a single blog so you could have the context in one place. The important areas are: not wrapping the ring; informing the consumers; batching for producers; and how multiple producers work. ProducerBarriers The Disruptor code has interfaces and helper classes for the Consumer s, but there's no interface for your producer, the thing that writes to the ring buffer.  That's because nothing else needs to access your producer, only you need to know about it.  However, like the consuming side, a ProducerBarrier is created by the ring buffer and your producer will use this to write to it. Writing to the ring buffer involves a two-phase commit.  First, your producer has to claim the next slot on the buffer.  Then, when the producer has finished writing to the slot, it will call commit on the ProducerBarrier . So let's look at the first bi
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Dissecting the Disruptor: How do I read from the ring buffer?

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The next in the series of understanding the Disruptor pattern developed at LMAX . After the last post we all understand ring buffers and how awesome they are.  Unfortunately for you, I have not said anything about how to actually populate them or read from them when you're using the Disruptor. ConsumerBarriers and Consumers I'm going to approach this slightly backwards, because it's probably easier to understand in the long run.  Assuming that some magic has populated it: how do you read something from the ring buffer? (OK, I'm starting to regret using Paint/ Gimp .  Although it's an excellent excuse to purchase a graphics tablet if I do continue down this road.  Also UML gurus are probably cursing my name right now.) Your Consumer is the thread that wants to get something off the buffer.  It has access to a ConsumerBarrier , which is created by the RingBuffer and interacts with it on behalf of the Consumer .  While the ring buffer obviously needs a se
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