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Showing posts from December, 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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Video: Why we shouldn't target women

If you have a Parleys subscription, you can watch the whole "Why we shouldn't target women" panel from Devoxx 2011 a month or so ago.  Watch me attempt to monopolise the whole panel as if it was my idea or something...
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How to make your CV Not Suck

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When you're applying for a job at LMAX , your CV (or résumé, for our American readers) usually comes through me and I decide whether to call you for a technical phone screen. I'm going to let you into a secret. I'm going to tell you the criteria I use when judging your CV. Now, you could say this is a foolish thing for me to do, because now when you apply you'll be "cheating" and writing your CV to pass these guidelines. Good. LMAX isn't the only company that's going to judge your CV based on these criteria. I firmly believe that an increase in quality of the CVs in our industry can only be A Good Thing.  An increase in the quality of your CV is definitely A Good Thing for you . Even more importantly, if I get CVs that do not pass these basic criteria, now I know you either don't read the LMAX blogs (shame on you), or you're not able to follow simple instructions (bodes poorly for your ability to learn within the company). The t...
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Video of our JAX London session

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At JAX London Mike and I presented "Understanding the Disruptor - A Beginner's Guide to Hardcore Concurrency".  This is the session we initially previewed to the London Java Community a few weeks earlier.  The content is the same, but the feel of the presentation was quite different to us - the venue for the LJC event was more intimate, and it was easier to interact with the audience.  At JAX, we were up on stage, which was pretty cool actually, but meant that it felt more like a lecture and it was less easy to connect with the audience. We received some really great feedback on this presentation, and it was brilliant to see a lot of the speakers from JAX there watching us.
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Interview by the Oracle Technology Network at Devoxx

Tori Wieldt from the Oracle Technology Network interviewed me at Devoxx.  Because I was there to be on the Why We Shouldn't Target Women panel, the interview is just another platform for me to air my views on this subject again. Yes, I am actually wearing pink....
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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 hea...
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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...
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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 n...
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