Messages in this thread | | | Date | Fri, 2 Mar 2007 11:27:14 +0100 | From | Pavel Machek <> | Subject | Re: [patch 00/13] Syslets, "Threadlets", generic AIO support, v3 |
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Hi!
> > > > If you can replace them with something simpler, and no worse than 10% > > > > slower in worst case, then go ahead. (We actually tried to do that at > > > > some point, only to realize that efence stresses vm subsystem in very > > > > unexpected/unfriendly way). > > > > > > Agh, only 10% in the worst case. > > > I think you can not even imagine what tricks network uses to get at > > > least aditional 1% out of the box. > > > > Yep? Feel free to rewrite networking to assembly on Eugenix. That > > should get you 1% improvement. If you reserve few registers to be only > > used by kernel (not allowed by userspace), you can speedup networking > > 5%, too. Ouch and you could turn off MMU, that is sure way to get few > > more percent improvement in your networking case. > > It is not _my_ networking, but taht one you use everyday in every Linux > box. Notice which tricks are used to remove single byte from > sk_buff.
Ok, so tricks were worth it in sk_buff case.
> It is called optimization, and if it does us a single plus it must be > implemented. Not all people have magical fear of new things.
But that does not mean "every optimalization must be implemented". Only optimalizations that are "worth it" are...
> > > Using such logic you can just abandon any further development, since it > > > work as is right now. > > > > Stop trying to pervert my logic. > > Ugh? :) > I just say in simple words your 'we do not need something if adds 10%, > but is complex to understand'.
Yes... but that does not mean "stop development". You are still free to clean up the code _while_ making it faster.
> > If your code is so complex that it is almost impossible to use from > > userspace, that is good enough reason not to be merged. "But it is 3% > > faster if..." is not a good-enough argument. > > Is it enough for you? > > epoll 4794.23 req/sec > kevent 6468.95 req/sec
Maybe. It is not up to me to decide. But "it is faster" is _not_ the only merge criterium. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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