Re: [libmicrohttpd] Performance problem under Windows

[Martin Bisson]

On 10/02/2011 4:01 PM, Martin Bisson wrote:
> On 09/02/2011 8:55 AM, Christian Grothoff wrote:
> > > I find the "little more than 1 second per request" a little suspicious.
> > > I looked at the code in daemon.c and both the select() and the poll()
> > > calls use a 1 second timeout...  I was wondering if there might be a
> > > problem with that under Windows...?  Or is the 1 second per request an
> > > expected latency for libmicrohttpd with client&  server on the same
> > > computer?
> > Well, I don't know how the 1s timeout in select relates to your 
> > performance
> > issue (have you tried changing it to 10s and seeing if performance 
> > goes down
> > accordingly), but what I can say is that MHD has no expected latency 
> > -- it
> > should be "instant" (as far as your OS/hardware can deliver).
> >
> > Now, 0.4.5 is of course ancient and various issues have been 
> > introduced and
> > fixed since (see ChangeLog), so I don't know if you're possibly 
> > hitting one of
> > those.
>
> Ok.  I rebuilt libmicrohttpd-0.9.6 and tried, still the same problem.  
> I changed the poll & select timeouts to 10 ms, no change.  I tried my 
> python script with a local Apache server, and I get low latency.
>
> But still, with libmicrohttpd, I get latencies that are slightly above 
> 1 s.  So I really feel, like something is still waiting for 1 s 
> somewhere.  I identified that the waiting is after my request is sent 
> and before my request-handling callback is called by libmicrohttpd, 
> but I don't really how to identify the problem...
>
> Any idea what to do next to get libmicrohttpd to respond faster?
>
> Thanks in advance,
>
> Martin

Hi,

I still have this 1 second latency problem.  I tried different threading 
models, even calling MHD_run() myself, but still, same 1 second latency 
problem.  Here are my 2 questions:

1) I would really appreciate if someone would run minimal_example.c (on 
port 8080), along with the python script attached with this e-mail, 
under Windows and tell me if they do have the same latency problem...  
Is my problem reproducible?

2) I guess my next step would be, with a debugger, to break during that 
1 second waiting period and see in what function libmicrohttpd is 
"stuck".  However, when I tried to debug minimal_example.c, no symbols 
are present and it exits with code 127 / 0177 / 0x7F.  I tried to 
compile with "./configure CFLAGS=-g && make".  Any pointers here on how 
to build and debug?  I familiar with debugging under Linux/gdb, but I've 
never debugged anything built with MinGW.  So any help would be appreciated.

Thanks again,

Martin

test.py
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