Sigmoid Social

ludwigpacificiOn deadlock free vs. starvation free: <a href="https://stackoverflow.com/questions/8370098/dead-lock-free-vs-starvation-free#32855505" rel="nofollow noopener" target="_blank">https://stackoverflow.com/questions/8370098/dead-lock-free-vs-starvation-free#32855505</a><a href="https://mastodon.sdf.org/tags/mutex" class="mention hashtag" rel="nofollow noopener" target="_blank">#mutex</a>

Hacker NewsLinux CLI tool to provide mutex locks for long running bash ops<a href="https://github.com/bigattichouse/waitlock" rel="nofollow noopener" translate="no" target="_blank">https://github.com/bigattichouse/waitlock</a><a href="https://mastodon.social/tags/HackerNews" class="mention hashtag" rel="nofollow noopener" target="_blank">#HackerNews</a> <a href="https://mastodon.social/tags/Linux" class="mention hashtag" rel="nofollow noopener" target="_blank">#Linux</a> <a href="https://mastodon.social/tags/CLI" class="mention hashtag" rel="nofollow noopener" target="_blank">#CLI</a> <a href="https://mastodon.social/tags/mutex" class="mention hashtag" rel="nofollow noopener" target="_blank">#mutex</a> <a href="https://mastodon.social/tags/locks" class="mention hashtag" rel="nofollow noopener" target="_blank">#locks</a> <a href="https://mastodon.social/tags/bash" class="mention hashtag" rel="nofollow noopener" target="_blank">#bash</a> <a href="https://mastodon.social/tags/scripting" class="mention hashtag" rel="nofollow noopener" target="_blank">#scripting</a> <a href="https://mastodon.social/tags/open" class="mention hashtag" rel="nofollow noopener" target="_blank">#open</a> <a href="https://mastodon.social/tags/source" class="mention hashtag" rel="nofollow noopener" target="_blank">#source</a> <a href="https://mastodon.social/tags/tools" class="mention hashtag" rel="nofollow noopener" target="_blank">#tools</a> <a href="https://mastodon.social/tags/GitHub" class="mention hashtag" rel="nofollow noopener" target="_blank">#GitHub</a>

Felix Palmen :freebsd: :c64:More interesting progress trying to make <a href="https://mastodon.bsd.cafe/tags/swad" class="mention hashtag" rel="nofollow noopener" target="_blank">#swad</a> suitable for very busy sites!I realized that <a href="https://mastodon.bsd.cafe/tags/TLS" class="mention hashtag" rel="nofollow noopener" target="_blank">#TLS</a> (both with <a href="https://mastodon.bsd.cafe/tags/OpenSSL" class="mention hashtag" rel="nofollow noopener" target="_blank">#OpenSSL</a> and <a href="https://mastodon.bsd.cafe/tags/LibreSSL" class="mention hashtag" rel="nofollow noopener" target="_blank">#LibreSSL</a>) is a *major* bottleneck. With TLS enabled, I couldn't cross 3000 requests per second, with somewhat acceptable response times (most below 500ms). Disabling TLS, I could really see the impact of a <a href="https://mastodon.bsd.cafe/tags/lockfree" class="mention hashtag" rel="nofollow noopener" target="_blank">#lockfree</a> queue as opposed to one protected by a <a href="https://mastodon.bsd.cafe/tags/mutex" class="mention hashtag" rel="nofollow noopener" target="_blank">#mutex</a>. With the mutex, up to around 8000 req/s could be reached on the same hardware. And with a lockfree design, that quickly went beyond 10k req/s, but crashed. 😆So I read some scientific papers 🙈 ... and redesigned a lot (*). And now it finally seems to work. My latest test reached a throughput of almost 25k req/s, with response times below 10ms for most requests! I really didn't expect to see *this* happen. 🤩 Maybe it could do even more, didn't try yet.Open issue: Can I do something about TLS? There *must* be some way to make it perform at least a *bit* better...(*) edit: Here's the design I finally used, with a much simplified "dequeue" because the queues in question are guaranteed to have only a single consumer: <a href="https://dl.acm.org/doi/10.1145/248052.248106" rel="nofollow noopener" translate="no" target="_blank">https://dl.acm.org/doi/10.1145/248052.248106</a>

Felix Palmen :freebsd: :c64:Nice, <a href="https://mastodon.bsd.cafe/tags/threadpool" class="mention hashtag" rel="nofollow noopener" target="_blank">#threadpool</a> overhaul done. Removed two locks (<a href="https://mastodon.bsd.cafe/tags/mutex" class="mention hashtag" rel="nofollow noopener" target="_blank">#mutex</a>) and two condition variables, replaced by a single lock and a single <a href="https://mastodon.bsd.cafe/tags/semaphore" class="mention hashtag" rel="nofollow noopener" target="_blank">#semaphore</a>. 😎 Simplifies the overall structure a lot, and it's probably safe to assume slightly better performance in contended situations as well. And so far, <a href="https://mastodon.bsd.cafe/tags/valgrind" class="mention hashtag" rel="nofollow noopener" target="_blank">#valgrind</a>'s helgrind tool doesn't find anything to complain about. 🙃Looking at the screenshot, I should probably make <a href="https://mastodon.bsd.cafe/tags/swad" class="mention hashtag" rel="nofollow noopener" target="_blank">#swad</a> default to *two* threads per CPU and expose the setting in the configuration file. When some thread jobs are expected to block, having more threads than CPUs is probably better.<a href="https://github.com/Zirias/poser/commit/995c27352615a65723fbd1833b2d36781cbeff4d" rel="nofollow noopener" translate="no" target="_blank">https://github.com/Zirias/poser/commit/995c27352615a65723fbd1833b2d36781cbeff4d</a>

alexanderadamNice read! <a href="https://ruby.social/@mamantoha" class="u-url mention" rel="nofollow noopener" target="_blank">@mamantoha</a> published a short and nice ✍️ blog post about 🚥 <a href="https://ruby.social/tags/semaphores" class="mention hashtag" rel="nofollow noopener" target="_blank">#semaphores</a> in :crystal: <a href="https://fosstodon.org/@CrystalLanguage" class="u-url mention" rel="nofollow noopener" target="_blank">@CrystalLanguage</a> at <a href="https://fosstodon.org/@thepracticaldev" class="u-url mention" rel="nofollow noopener" target="_blank">@thepracticaldev</a>:<a href="https://dev.to/mamantoha/semaphores-in-crystal-5eha" rel="nofollow noopener" translate="no" target="_blank">https://dev.to/mamantoha/semaphores-in-crystal-5eha</a><a href="https://ruby.social/tags/CrystalLang" class="mention hashtag" rel="nofollow noopener" target="_blank">#CrystalLang</a> <a href="https://ruby.social/tags/CrystalLanguage" class="mention hashtag" rel="nofollow noopener" target="_blank">#CrystalLanguage</a> <a href="https://ruby.social/tags/concurrency" class="mention hashtag" rel="nofollow noopener" target="_blank">#concurrency</a> <a href="https://ruby.social/tags/waitgroup" class="mention hashtag" rel="nofollow noopener" target="_blank">#waitgroup</a> <a href="https://ruby.social/tags/mutex" class="mention hashtag" rel="nofollow noopener" target="_blank">#mutex</a> <a href="https://ruby.social/tags/parallel" class="mention hashtag" rel="nofollow noopener" target="_blank">#parallel</a> <a href="https://ruby.social/tags/paralellism" class="mention hashtag" rel="nofollow noopener" target="_blank">#paralellism</a> <a href="https://ruby.social/tags/concurrency" class="mention hashtag" rel="nofollow noopener" target="_blank">#concurrency</a> <a href="https://ruby.social/tags/programming" class="mention hashtag" rel="nofollow noopener" target="_blank">#programming</a> <a href="https://ruby.social/tags/crystal" class="mention hashtag" rel="nofollow noopener" target="_blank">#crystal</a>

cyclical_obsessive<a href="https://mastodon.social/@themagpi" class="u-url mention" rel="nofollow noopener" target="_blank">@themagpi</a> > Raspberry Pi projects?Solved a month long mystery! How to manage Raspberry Pi I2C device access inside ROS2/Ubuntu/Docker container **AND** outside the container in Raspberry PiOS Bookworm? Docker invocation must map both the bus AND the mutex lock folder /var/lock/ <a href="https://fosstodon.org/tags/RaspberryPi5" class="mention hashtag" rel="nofollow noopener" target="_blank">#RaspberryPi5</a> <a href="https://fosstodon.org/tags/RaspberryPiOS" class="mention hashtag" rel="nofollow noopener" target="_blank">#RaspberryPiOS</a> <a href="https://fosstodon.org/tags/I2C" class="mention hashtag" rel="nofollow noopener" target="_blank">#I2C</a> <a href="https://fosstodon.org/tags/Mutex" class="mention hashtag" rel="nofollow noopener" target="_blank">#Mutex</a> <a href="https://fosstodon.org/tags/Docker" class="mention hashtag" rel="nofollow noopener" target="_blank">#Docker</a> <a href="https://fosstodon.org/tags/ROS2humble" class="mention hashtag" rel="nofollow noopener" target="_blank">#ROS2humble</a> <a href="https://fosstodon.org/tags/Robot" class="mention hashtag" rel="nofollow noopener" target="_blank">#Robot</a> <a href="https://fosstodon.org/tags/GoPiGo3" class="mention hashtag" rel="nofollow noopener" target="_blank">#GoPiGo3</a>

cyclical_obsessive<a href="https://fosstodon.org/@drfootleg" class="u-url mention" rel="nofollow noopener" target="_blank">@drfootleg</a> Another tip that has been plaguing me for a month! If you have processes inside a Docker container and other processes outside the Docker container that need mutex protection such as I2C bus or SPI bus accesses, you need to map the bus (obviously) **and** the mutex folder! I had the sensor access working great but could not figure out why my inside and outside "mutex protected" accesses were colliding...<a href="https://fosstodon.org/tags/GoPiGo3" class="mention hashtag" rel="nofollow noopener" target="_blank">#GoPiGo3</a> <a href="https://fosstodon.org/tags/Docker" class="mention hashtag" rel="nofollow noopener" target="_blank">#Docker</a> <a href="https://fosstodon.org/tags/RaspberryPiOS" class="mention hashtag" rel="nofollow noopener" target="_blank">#RaspberryPiOS</a> <a href="https://fosstodon.org/tags/mutex" class="mention hashtag" rel="nofollow noopener" target="_blank">#mutex</a> <a href="https://fosstodon.org/tags/ros2humble" class="mention hashtag" rel="nofollow noopener" target="_blank">#ros2humble</a>

cyclical_obsessiveThink I solved why my inside Docker (ROS 2) access to I2C INA219 current sensor was colliding with my outside Docker access to the device - forgot to map the /var/lock directory so the mutex is visible from both environments!<a href="https://fosstodon.org/tags/Docker" class="mention hashtag" rel="nofollow noopener" target="_blank">#Docker</a> <a href="https://fosstodon.org/tags/mutex" class="mention hashtag" rel="nofollow noopener" target="_blank">#mutex</a> <a href="https://fosstodon.org/tags/ina219" class="mention hashtag" rel="nofollow noopener" target="_blank">#ina219</a> <a href="https://fosstodon.org/tags/robot" class="mention hashtag" rel="nofollow noopener" target="_blank">#robot</a> <a href="https://fosstodon.org/tags/GoPiGo3" class="mention hashtag" rel="nofollow noopener" target="_blank">#GoPiGo3</a> <a href="https://fosstodon.org/tags/ros2humble" class="mention hashtag" rel="nofollow noopener" target="_blank">#ros2humble</a>

IT NewsMake Your Code Slower With Multithreading - With the performance of modern CPU cores plateauing recently, the main performance... - <a href="https://hackaday.com/2024/06/07/make-your-code-slower-with-multithreading/" rel="nofollow noopener" translate="no" target="_blank">https://hackaday.com/2024/06/07/make-your-code-slower-with-multithreading/</a> <a href="https://schleuss.online/tags/multithreading" class="mention hashtag" rel="nofollow noopener" target="_blank">#multithreading</a> <a href="https://schleuss.online/tags/softwarehacks" class="mention hashtag" rel="nofollow noopener" target="_blank">#softwarehacks</a> <a href="https://schleuss.online/tags/performance" class="mention hashtag" rel="nofollow noopener" target="_blank">#performance</a> <a href="https://schleuss.online/tags/profiling" class="mention hashtag" rel="nofollow noopener" target="_blank">#profiling</a> <a href="https://schleuss.online/tags/spinlocks" class="mention hashtag" rel="nofollow noopener" target="_blank">#spinlocks</a> <a href="https://schleuss.online/tags/syscall" class="mention hashtag" rel="nofollow noopener" target="_blank">#syscall</a> <a href="https://schleuss.online/tags/futex" class="mention hashtag" rel="nofollow noopener" target="_blank">#futex</a> <a href="https://schleuss.online/tags/mutex" class="mention hashtag" rel="nofollow noopener" target="_blank">#mutex</a> <a href="https://schleuss.online/tags/perf" class="mention hashtag" rel="nofollow noopener" target="_blank">#perf</a>

we compiled different<a href="https://mastodon.social/tags/tui" class="mention hashtag" rel="nofollow noopener" target="_blank">#tui</a> <a href="https://mastodon.social/tags/daw" class="mention hashtag" rel="nofollow noopener" target="_blank">#daw</a> for <a href="https://mastodon.social/tags/jack" class="mention hashtag" rel="nofollow noopener" target="_blank">#jack</a> in <a href="https://mastodon.social/tags/rustlang" class="mention hashtag" rel="nofollow noopener" target="_blank">#rustlang</a> Rewrote the UI of the <a href="https://mastodon.social/tags/midi" class="mention hashtag" rel="nofollow noopener" target="_blank">#midi</a> sequencer with <a href="https://mastodon.social/tags/ratatui" class="mention hashtag" rel="nofollow noopener" target="_blank">#ratatui</a> for double buffering.We're polyphonic now! Multithreaded, too - I put a <a href="https://mastodon.social/tags/mutex" class="mention hashtag" rel="nofollow noopener" target="_blank">#mutex</a> between input/render/audio threads instead of message passing.Doesn't even properly support Note Off events yet, but it does play a mean cheerful dirge. Playback cursor position still off, though.Hooking this up to the VST host every time I restart either is bit of a faff. Gotta teach it to auto-connect the MIDI/audio ports...

lambdageekDebugging lock ordering inversions 😫 <a href="https://mastodon.social/tags/softwareEngineering" class="mention hashtag" rel="nofollow noopener" target="_blank">#softwareEngineering</a> <a href="https://mastodon.social/tags/concurrency" class="mention hashtag" rel="nofollow noopener" target="_blank">#concurrency</a> <a href="https://mastodon.social/tags/mutex" class="mention hashtag" rel="nofollow noopener" target="_blank">#mutex</a> <a href="https://mastodon.social/tags/lock" class="mention hashtag" rel="nofollow noopener" target="_blank">#lock</a> <a href="https://mastodon.social/tags/lockOrder" class="mention hashtag" rel="nofollow noopener" target="_blank">#lockOrder</a> <a href="https://mastodon.social/tags/debugging" class="mention hashtag" rel="nofollow noopener" target="_blank">#debugging</a>

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