Programming

23281 readers

327 users here now

Welcome to the main community in programming.dev! Feel free to post anything relating to programming here!

Cross posting is strongly encouraged in the instance. If you feel your post or another person's post makes sense in another community cross post into it.

Hope you enjoy the instance!

Rules

Follow the programming.dev instance rules
Keep content related to programming in some way
If you're posting long videos try to add in some form of tldr for those who don't want to watch videos

Wormhole

Follow the wormhole through a path of communities !webdev@programming.dev

founded 2 years ago

MODERATORS

snowe@programming.dev

Ategon@programming.dev

MaungaHikoi@lemmy.nz

UlrikHD@programming.dev

Using black magic to make a fast circular buffer. (lo.calho.st)

submitted 9 months ago by beejjorgensen@lemmy.sdf.org to c/programming@programming.dev

3 comments fedilink hide all child comments

Neat article about avoiding a memcpy in a circular buffer.

you are viewing a single comment's thread
view the rest of the comments

[–] drspod@lemmy.ml 13 points 9 months ago

The nice thing about circular buffers is that they can be made lock-free by making each pointer only ever modified by one function, ie. get modifies the head and put modifies the tail.

The solution in the article modifies both head and tail in the get function (when subtracting the page size to put the buffer back into the first page) which makes synchronization necessary to avoid races.

The author could actually make this implementation lock-free too, by making only the get function perform the subtraction on the head whilst the put function performs the subtraction on the tail.

You would then just need a little bit of extra logic when calculating the current size, but then you'd have a lock-free data structure.