Re: latest linus-2.5 BK broken

[Cort Dougan <cort@fsmlabs.com>]

I agree with you there.  It's not easy, and I'd claim it's not possible
given that no-one has done it yet, to have a select() call that is speedy
for both 0-10 and 1k file descriptors.


} I take issue with the statement that select scales fine to thousands of 
} file descriptors.  It doesn't.  For fairly trivial workloads it degrades 
} to 0 operations per second with more than a few dozen filedescriptors in 
} the array, but only one descriptor being active.  To sustain decent 
} throughput, select needs something like 50% of the filedescriptors in an 
} array to be active at every select() call, which makes in unsuitable for 
} things like LDAP servers, or HTTP/FTP where the clients are behind slow 
} connections or interactive (like in the real world).  I've benchmarked 
} it -- we should really include something like /dev/epoll in the kernel 
} to improve this case.
} 
} Still, I think the bitmap approach in this case is useful, as having 
} affinity to multiple CPUs can be needed, and it is not a frequently 
} occuring operation (unlike select()).
} 
} 		-ben
} -- 
} "You will be reincarnated as a toad; and you will be much happier."
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