On Thu, Aug 27 2009, Tejun Heo wrote: > Hello, Jens. > > Jens Axboe wrote: > >> It would be nice if merging of this series and the lazy work can be > >> held a bit but there's no harm in merging either. If the concurrency > >> managed workqueue turns out to be a good idea, we can replace it then. > > > > It can wait, what you describe above sounds really cool and would > > hopefully allow us to get rid of all workqueues (provided it scales well > > and doesn't fall down on cache line contention with many different > > instances pounding on it). > > Almost all operations are per-cpu so cache lines shouldn't bounce too > much. The only part I worry about is the part which checks whether a > work is currently executing on the current cpu which currently is > implemeted as a hash table. The hash table is only 16 pointers long > and will be mostly empty so hopefully it doesn't add any significant > overhead. OK, we'll let time and experimentation be the judge. > > Care to post it? I know you don't think it's perfect yet, but it would > > make a lot more sense to throw effort into this rather than waste time > > on partial solutions. > > I have this printed out code with full of red markings from proof > reading and flush implementation is mostly broken. Please give me a > couple of days. I'll post a rough unsplit version which at least > compiles with the planned changes applied by the end of the week. :-) Alright, fair enough. One question - do the 'exposed' workqueues (the ones that drivers allocate/create) sitting in front of the global cpu queue allow more than one thread per cpu, or is that property retained for the global cpu queue (where it is a necessity)? -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
