Messages in this thread | | | Date | Mon, 9 Mar 1998 13:30:47 +1100 | From | Richard Gooch <> | Subject | Re: mmap() versus read() |
| |
Dean Gaudet writes: > > > On Mon, 9 Mar 1998, Richard Gooch wrote: > > > How long does it take to service and complete a transaction, assuming > > all data is in RAM? > > I haven't put it into an environment where I can test it and be happy that > I'm producing real-life answers. It should be essentially "as fast as the > kernel can shovel from the disk/ram to the net and deal with context > switches". If anyone wants the required patches to 1.3 to play with this > contact me off-list... it won't be part of apache-1.3 it was just an > experiment: "if I go over the top, and throw portability and features out > the window, can I get rid of all the syscalls?".
OK, so lets invent some numbers. Say you are on a 100 Mb/s network. Let's pretend that you get that bandwidth all the way from the server to the browser (unlikely). So that's 10 MBytes/sec. If we transfer a 1 kByte message, that's 100 microseconds just to *transfer*. If a syscall takes a couple of microseconds, that overhead is pretty minimal.
> Apache-1.3 will take a minimum of um, 9 per request I think the number > is... three of them are signal manipulations, two are calls to time(), and > there's open/mmap/munmap/close. On top of that there are another 10 or so > required to set up and tear down the connection -- which are amortized on > persistant connections.
Well, chuck out the signal manipulation for a start :-)
Regards,
Richard....
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu
| |