Messages in this thread | | | Date | Thu, 30 Oct 1997 08:44:36 -0500 (EST) | From | "Richard B. Johnson" <> | Subject | Re: Unix domain sockets being slooooooooooooooooooooooooowwwwwwwww |
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On Thu, 30 Oct 1997, Alan Cox wrote:
> > I think there's a minimum packet length over ethernet that is killing you > > with overhead. I think it's 64 bytes. If you have a 1-byte semaphore, you > > are only using about 1/64th of the available data bandwidth. > > The actual wasted 63 bytes is but a tiny fraction of the cost of getting > a packet to wire - a lot of it is going to the hardware setup overheads, > and even the linux syscall overhead too > > Effectively its an equation of the form > > large_overhead+(small_cost*bytes) > --------------------------------- > bytes > > which means small messages get you into poor performance areas. Doing it > with tcp not udp really makes it fun > Alan,
I was careful to use the words "data bandwidth", i.e., the bandwidth available for useful stuff. This takes all the (enormous) built-in overhead and normalizes it out of the way.
Cheers, Dick Johnson
Richard B. Johnson Project Engineer Analogic Corporation Penguin : Linux version 2.1.60 on an i586 machine (66.15 BogoMips). Warning : It's hard to remain at the trailing edge of technology.
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