Messages in this thread | | | Date | Thu, 11 Nov 1999 23:47:35 -0800 | From | Dan Kegel <> | Subject | Re: Max tcp connections |
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David Schwartz wrote: > > Signal based I/O is definitely the right approach for scaling > > I still find this very hard to believe. How can one fast pass through poll > (assuming a smarter implementation) be less efficient than the OS sending me > 5,000 signals? That strikes me as an incredible claim.
Easy. The kernel doesn't send you 5,000 signals. If the signal queue starts overflowing, it gives up and sends you a single SIGIO, and you call poll().
The signal model gives you the best of both worlds: low overhead when only a few fd's at a time need attention (no linear scan), and low overhead when they all do (same as old poll() method, but with the extra overhead of a single SIGIO).
sct must be sleeping, or he would have answered like this, I think :-) - Dan
-- (The above is just my personal opinion; I don't speak for my employer, except on the occasional talk show.)
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