Hi Christian,
My application runs on fedora and is single threaded, for my testing
application just receives the request and responds with 200OK with some
json body (size <100 bytes )in the response.
I did try running strace on MHD this is what I got. (client I am using
libcurl application which sends 33k of body in http post with out Expect
100 header)
14:38:14.623432 epoll_wait(12, [{EPOLLIN|EPOLLOUT, {u32=21908544,
u64=21908544}}], 128, 0) = 1
*14:38:14.623509 recvfrom(13, "POST /hello/TestMsg/async"..., 16384, 0,
NULL, NULL) = 16384*
14:38:14.623825 rt_sigprocmask(SIG_UNBLOCK, [HUP QUIT PIPE ALRM TERM CHLD
CONT TSTP TTIN TTOU WINCH IO PWR], NULL, 8) = 0
14:38:14.623880 epoll_wait(5, [], 2, 50) = 0
14:38:14.674038 rt_sigprocmask(SIG_BLOCK, [HUP QUIT PIPE ALRM TERM CHLD
CONT TSTP TTIN TTOU WINCH IO PWR], NULL, 8) = 0
14:38:14.674135 epoll_wait(12, [], 128, 0) = 0
*14:38:14.674175 recvfrom(13, "ey\": \"4\"\n},{\n \"key\": \"0\",\n
"..., 15919, 0, NULL, NULL) = 15919*
14:38:14.674329 rt_sigprocmask(SIG_UNBLOCK, [HUP QUIT PIPE ALRM TERM CHLD
CONT TSTP TTIN TTOU WINCH IO PWR], NULL, 8) = 0
14:38:14.674375 epoll_wait(5, [], 2, 50) = 0
14:38:14.724568 rt_sigprocmask(SIG_BLOCK, [HUP QUIT PIPE ALRM TERM CHLD
CONT TSTP TTIN TTOU WINCH IO PWR], NULL, 8) = 0
14:38:14.724666 epoll_wait(12, [], 128, 0) = 0
*14:38:14.724715 recvfrom(13, "key\": \"3\",\n \"key\": \"4\"\n},{\n
"..., 15919, 0, NULL, NULL) = 1878*
....
....
14:38:14.743832 setsockopt(13, SOL_TCP, TCP_NODELAY, [0], 4) = 0
14:38:14.743908 setsockopt(13, SOL_TCP, TCP_CORK, [1], 4) = 0
*14:38:14.743949 sendto(13, "HTTP/1.1 200 OK\r\nConnection: Kee"..., 162,
MSG_NOSIGNAL, NULL, 0) = 162*
14:38:14.744022 setsockopt(13, SOL_TCP, TCP_CORK, [0], 4) = 0
14:38:14.744189 setsockopt(13, SOL_TCP, TCP_NODELAY, [1], 4) = 0
14:38:14.744234 setsockopt(13, SOL_TCP, TCP_NODELAY, [0], 4) = 0
14:38:14.744286 setsockopt(13, SOL_TCP, TCP_CORK, [1], 4) = 0
Time diff I see is about 120 milli secs between MHD receiving request and
sending response to the client.
With this I got to understand that TCP_CORK and TCP_NODELAY is kind off
delaying the response being sent out on transport layer...
Is their a way to always enable TCP_NODELAY on MHD ? and check if we see
this delay on transport layer ?
Thanks in advance,
Badari
On Sat, Nov 10, 2018 at 11:53 PM Christian Grothoff <[email protected]>
wrote:
> On 11/9/18 5:44 PM, Badari Prasad wrote:
> > Hi,
> > I was going through old mailist archives, found one thread on
> > TCP_NODELAY
> > : https://lists.gnu.org/archive/html/libmicrohttpd/2015-11/msg00077.html
> > But couldn't know if the option provided is it at compile time flag or
> > runtime flag per connection basis.
> >
> > Kindly let me know the information on TCP_NODELAY option at MHD.
>
> Hi!
>
> To the best of my knowledge (i.e. unless there is a bug), TCP_NODELAY
> should be set/unset by MHD automatically whenever it makes sense to do
> so. Your application doesn't need to do anything here.
>
> If you find/suspect that corking is inappropriately used, please send a
> packet trace and maybe a bit of explanation as to how your code works
> (in particular, which platform you use and which threading mode is in use).
>
> Happy hacking!
>
> Christian
>
>
