Re: sendfile in darwin

[Mads Toftum]

On Wed, May 07, 2008 at 02:50:46PM -0400, Jim Jagielski wrote:
> To clarify: I have no idea what you are referring to
> as far as what issue you were discussing. This is
> because it was on IRC. For myself and everyone else who
> did not happen to be on IRC at that moment of time, we
> have no idea what this is all about.
>
18:26 < dirkx> Quick thought anyone.... with a"curl --silent -o
/dev/null -vv http://localhost:8080/manual/images/feather.gif"; on a
basic apache (default install, yadayada) on macosx -- response is
immediate.

18:27 < dirkx> But with curl --silent -o /dev/null -vv
http://localhost:8080/manual/images/feather.gif?x --- note the ?x at the
end -- delay of 2-3 seconds before the reply is streamed on the wire.

18:54 < dirkx> Ah - if I use the '-X' flag -- it is virtually always
there.

19:01 < dirkx> Hmm - a 'Connection: close' in the request header sorts
it out sure.
19:01 < dirkx> Kind of interesting -- dtrace() shows you:
19:01 < dirkx>
open("/Users/dirkx/tmp/apache-httpd-26044/manual/images/feather.gif\0",
0x0, 0x0)II = 10 0
19:02 < dirkx> etsockopt(0x9, 0x6, 0x1)II = 0 0
19:02 < dirkx> setsockopt(0x9, 0x6, 0x4)II = 0 0
19:02 < dirkx> writev(0x9, 0xBFFFEE74, 0x1)II = 245 0
19:02 < dirkx> sendfile(0xA, 0x9, 0x0)II = 0 0
19:02 < dirkx> ... write to log file ...
19:02 < dirkx> close(0xA)II = 0 0
19:02 < dirkx> read(0x9, " ---> returns -1
19:02 < dirkx> ... then waits....
19:02 < dirkx> waits...
19:03 < dirkx> And then the actual reply goes out by TCP simultaneous
with:
19:03 < dirkx> poll(0xBFFFF228, 0x1, 0x1388)II = 1 0
19:03 < dirkx> read(0x9, "\0", 0x1F40)II = 0 0
19:03 < dirkx> shutdown(0x9, 0x1, 0x173460)II = 0 0
19:03 < dirkx> poll(0xBFFFF558, 0x1, 0x7D0)II = 1 0
19:03 < dirkx> read(0x9, "\0", 0x200)II = 0 0
19:03 < dirkx> close(0x9)II = 0 0
19:03 < dirkx> read(0x5, "\0", 0x1)II = -1 Err#35
19:03 < dirkx> As if the 'sendfile' 'hangs' until that happens.

I think that's all of it.

vh

Mads Toftum
-- 
http://soulfood.dk