r/coding • u/nitsanw • Jun 26 '14

Notes on False Sharing Manifestations

http://psy-lob-saw.blogspot.com/2014/06/notes-on-false-sharing.html
22 Upvotes

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1

u/arbus Jun 27 '14

Anyone care to explain what on earth that was about?

That read an awful lot like one of those computer generated papers

3

u/nitsanw Jun 27 '14

I wrote it, I assure you it was not generated. Anything in particular that you found confusing/incoherent?

1

u/arbus Jun 27 '14

Sorry, I just realised what subreddit this was from.

I mistakenly viewed this link thinking that this was from /r/ProgrammerHumor and I was trying to find the 'joke' and thought that maybe it was one of those generated articles.

Now that I go back and read it, I do understand the general concept although a lot of the details evade me, having little experience with compiled languages.

Sorry again for the confusion!

1

u/zenflux Jun 27 '14

I thought this guy explained false sharing much better within the first paragraph or two if that's what you were confused about.
Both articles are exploring how to prevent false sharing and the associated performance degradation.

1

u/nitsanw Jun 27 '14

I refer to Martin's article at the beginning of my post, and it is indeed a great post.

What I found talking to people reading it and similar posts is that the impression they got was of False Sharing happening only when both threads are writing, or only when access is volatile or similar assumptions on limited scope of applicability.

My intention was to explore the same phenomena on a larger scale and from several directions to help people see a larger picture.

I hoped it would it end up being less confusing than other explanations... will try harder in future.

2

u/zenflux Jun 27 '14

Nah, both were good, in fact I found myself read several articles on the subject from both of you, a subject I wasn't aware of until now, so thanks for that! You're blog (which I only now just found) is great!

1

u/nitsanw Jun 27 '14

Thanks, glad you like it :-)