> "John S. Dyson" <dy...@iquest.net> writes: > > > Finegrained locking either requires developers with IQ's of 200 or higher, > > or a different kernel structure. I suggest that finegrained locking is > > cool, > > and can be intelligently used to mitigate (but not solve) the effects of > > lots of problems > > Fine grained locking is hard - but it isn't exactly rocket > science. It's been tackled in a number of OSes, papers have been > written about it. > I also have played with the SVR4 SMP kernel (the real working one), not some of the toys that called themselves SMP -- but later versions were much better than even what I worked on. I can say that the maintainability of the code sucked, and the problems were due to the ARCHITECTURE of the original kernel. Sure, it can be done, but it has to be done methodically, and simple non-SMP changes preciptate massive SMP changes.
The typical monlithic kernels are just the right answer to the wrong problem, if you are talking optimal SMP solutions. > > Sure. But 2 and 4-way boxes are becoming more and more mainstream. And > any IO bound job is not going to perform well on FreeBSD because of > giant locking. > I agree. However, I suggest that finegrained locking will be a loosing proposition. Something in-between is probably good. My brains got fried on trying to figure out a GOOD solution for the FreeBSD kernel. There are no GOOD solutions, but a reasonable compromise is some kind of medium grained scheme. John To Unsubscribe: send mail to majord...@freebsd.org with "unsubscribe freebsd-hackers" in the body of the message
