Messages in this thread | | | Date | Tue, 27 Feb 2007 11:49:57 +0100 | From | Ingo Molnar <> | Subject | Re: [patch 00/13] Syslets, "Threadlets", generic AIO support, v3 |
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* Evgeniy Polyakov <johnpol@2ka.mipt.ru> wrote:
> > does that work for you? > > Yes, -fomit-frame-point make the deal. > > In average, threadlet runs as fast as epoll.
yeah.
> Just because there are _no_ rescheduling in that case.
in my test it was 'little', not 'no'. But yes, that's exactly my point: we can remove the nonblock hackeries from event loops and just concentrate on making it schedule in less than 10-20% of the cases. Even a relatively high 10-20% rescheduling rate is hardly measurable with threadlets, while it gives a 10%-20% regression (and possibly bad latencies) for the pure epoll/kevent server.
and such a mixed technique is simply not possible with ordinary user-space threads, because there it's an all-or-nothing affair: either you go fully to threads (at which point we are again back to a fully threaded design, now also saddled with event loop overhead), or you try to do user-space threads, which Just Make Little Sense (tm).
so threadlets remove the biggest headache from event loops: they dont have to be '100% nonblocking' anymore. No O_NONBLOCK overhead, no complex state machines - just handle the most common event type via an outer event loop and keep the other 99% of server complexity in plain procedural programming. 1% of state-machine code is perfectly acceptable.
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