[HN Gopher] Fine-grained locking with two-bit mutexes ___________________________________________________________________ Fine-grained locking with two-bit mutexes Author : ibobev Score : 19 points Date : 2022-12-06 16:41 UTC (1 days ago) (HTM) web link (probablydance.com) (TXT) w3m dump (probablydance.com) | bawolff wrote: | Sligtly off topic, but did anyone else do a double-take at the | "make $1000 donation" form at the bottom? | meta2023 wrote: | Readable font-sizes don't come cheap! | 95014_refugee wrote: | Owner tracking and priority inheritance, anyone? | bcrl wrote: | We used simple bit spinlocks early in the multiprocessor | scalability work done on the Linux kernel. While nearly "optimal" | in terms of memory usage and simplicity, they tend to fall apart | rather dramatically on systems with higher core counts. But | they're a great step in the process of learning how to walk | before running on bigger MP systems... | the_optimist wrote: | Can you elaborate and reference more on the "fall-apart" and | approaches with more cores? | arberx wrote: | An efficient spinlock relies on a good kernel scheduler. I | imagine that's the biggest hindrance to performance in a | multicore system. | gpderetta wrote: | Note the mutex discussed in the article is not a spin lock, it | actually sleeps on contention. | zamalek wrote: | One thing to be careful of is that mutexes are fair, spinlocks | are not. It is possible for a worker to wait indefinitely behind | workers acquiring the lock at a later time. | connicpu wrote: | Mutexes aren't necessarily fair, and there's some good reasons | you may not want true fairness in your lock[1] (that said, most | implementations try to be as fair as they can be without | introducing too much overhead) | | [1]: http://joeduffyblog.com/2006/12/14/anticonvoy-locks-in- | windo... ___________________________________________________________________ (page generated 2022-12-07 23:01 UTC)