Messages in this thread |  | | Date | Wed, 18 Sep 2002 12:33:53 -0600 | From | yodaiken@fsmlabs ... | Subject | Re: [patch] lockless, scalable get_pid(), for_each_process() elimination, 2.5.35-BK |
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On Wed, Sep 18, 2002 at 08:21:38PM +0200, Ingo Molnar wrote: > > On Wed, 18 Sep 2002 yodaiken@fsmlabs.com wrote: > > > So Solaris made a stupid design decision to encourage people to use a > > thread per call on these big systems and Linux should make the same > > decision for compatibility? > > if it can be done, why not? Do you advocate the using of big select() > loops and userspace threading libraries?
I like request/servers and state machines. I also think that there may be some smart ways to fold multiple threads into one. And there is nothing wrong with userspace threading libraries.
> i have to admit that there's an inherent simplicity in using one thread > per line, and for the more critical systems it's the simplicity that
There is a simplicity acquired by pushing the complexity to somewhere else.
> matters alot. One process per line would be even nicer - but that has a > much higher resource footprint. While it could all be rewritten into a > IRQ-driven state-machine as well, i dont think that is economic nor > manageable for every case. Guess why Apache is still using the model of > threads/processes, with a serial workflow done by them, and not the model > of an async state-machine that TUX uses.
Because Linux does not provide an easy and highly efficient API for building state machines and because even if it did, a crappy threads model that runs on NT as well as Linux is more attractive.
> > I can see why people want this: they have huge ugly systems that they > > would like to port to Linux with as little effort as possible. But it's > > not free for the OS either. > > i believe if you do not see the dangers of O(N^2) algorithms then you > should not do RT coding. While it's not at all the goal of the patch i > sent, with some effort we can make Linux to behave in an RT-correct way if > a subset of APIs are used and drivers are carefully controlled.
Huh? Just for information, don't try to apply asymptotic analysis blindly to bounded conditions.
-- --------------------------------------------------------- Victor Yodaiken Finite State Machine Labs: The RTLinux Company. www.fsmlabs.com www.rtlinux.com
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