[vlc-devel] http performance issue

[Sébastien Escudier]

> Do I assume you are using broadcast mode?

right

> That would hint that the HTTP daemon core is very much not scalable, which
> is quite possible.
> With RTSP, there is one sending thread per elementary (RTP) stream, plus
> one thread doing all the signaling. With HTTP there is one thread doing
> everything for the whole system.

ok, thank you for the explanation.

I also did some profiling with oprofiled, I paste results here in case it is
useful for someone.
I am not able to use gprof (--enable-gprof works, but gmon.out is almost empty),
even with this wrapper :
http://sam.zoy.org/writings/programming/gprof.html

So here is 2 oprofiled results, the first one is with 2 clients on the same http
stream, the second one is with 2 clients on 2 different streams (and cpu goes
from 1% to 50% on my computer).
The main difference I can see is librt-2.7.so % usage, and number of sample for
top 3 libs (x10). Note that both tests have the same duration.


***********************
2 clients on one video
***********************

     8728  3.8355 vlc-static
	CPU_CLK_UNHALT...|
	  samples|      %|
	------------------
	     1959 22.4450 libc-2.7.so
	     1950 22.3419 libvlccore.so.1.0.0
	     1135 13.0041 libpthread-2.7.so
	      943 10.8043 librt-2.7.so
	      915 10.4835 liblive555_plugin.so
	      686  7.8598 libpacketizer_mpeg4video_plugin.so
	      625  7.1609 libmux_ts_plugin.so
	      295  3.3799 [vdso] (tgid:16905 range:0xb7f3b000-0xb7f3c000)
	      103  1.1801 ld-2.7.so
	       40  0.4583 libstdc++.so.6.0.9
	       27  0.3093 libaccess_output_http_plugin.so
	       21  0.2406 libstream_out_standard_plugin.so
	       21  0.2406 libdvbpsi.so.4.0.0
	        5  0.0573 libpacketizer_mpeg4audio_plugin.so
	        2  0.0229 libgcc_s.so.1
	        1  0.0115 libdl-2.7.so

**********************************
2 clients on different videos
**********************************
    69467 17.2474 vlc-static
	CPU_CLK_UNHALT...|
	  samples|      %|
	------------------
	    22119 31.8410 librt-2.7.so
	    19765 28.4524 libvlccore.so.1.0.0
	    15765 22.6942 libpthread-2.7.so
	     5788  8.3320 libc-2.7.so
	     3754  5.4040 [vdso] (tgid:17375 range:0xb7f50000-0xb7f51000)
	      845  1.2164 liblive555_plugin.so
	      610  0.8781 libpacketizer_mpeg4video_plugin.so
	      582  0.8378 libmux_ts_plugin.so
	      111  0.1598 ld-2.7.so
	       41  0.0590 libaccess_output_http_plugin.so
	       40  0.0576 libstdc++.so.6.0.9
	       24  0.0345 libdvbpsi.so.4.0.0
	       17  0.0245 libstream_out_standard_plugin.so
	        1  0.0014 libaccess_mmap_plugin.so
	        1  0.0014 liblpcm_plugin.so
	        1  0.0014 libxtag_plugin.so
	        1  0.0014 libpacketizer_mpeg4audio_plugin.so
	        1  0.0014 libgcc_s.so.1
	        1  0.0014 libdl-2.7.so