index % time self children called name 0.00 0.00 100/100 tt [3] [1] 0.0 0.00 0.00 100 aa [1] ----------------------------------------------- 0.00 0.00 100/100 tt [3] [2] 0.0 0.00 0.00 100 bb [2] ----------------------------------------------- 0.00 0.00 100/100 main [9] [3] 0.0 0.00 0.00 100 tt [3] 0.00 0.00 100/100 aa [1] 0.00 0.00 100/100 bb [2] -----------------------------------------------
아무튼 아래와 같은 형식의 출력이 보이는데, 참 봐도 무슨 소리인지 모르겠다.
간단하게 생각하자면
[%d] 값은 함수이고, 숫자 나온 것에 대한 구조를 보여준다.
[1] 은 aa() 를 실행한 녀석이 tt() 이라는 의미이고
[2] 는 bb() 를 실행한 녀석이 tt()
[3] 는 tt()를 실행한 녀석이 main() 이라는 이야기이다.
tt()
{
aa();
bb();
}
main()
{
tt();
}
이런 구조를 지니게 된다.
만약, 하나의 함수를 여러개에서 호출한다면
위와 같이 [%d] 위에 하나씩 있는게 아니라 여러개가 나타나게 된다.
아래는 Kprof에서 실행한 결과이다.(main 함수는 어디로 가출한겨 ㄱ-)
$ gprof Flat profile:
Each sample counts as 0.01 seconds. no time accumulated
% cumulative self self total time seconds seconds calls Ts/call Ts/call name 0.00 0.00 0.00 100 0.00 0.00 aa 0.00 0.00 0.00 100 0.00 0.00 bb 0.00 0.00 0.00 100 0.00 0.00 tt
% the percentage of the total running time of the time program used by this function.
cumulative a running sum of the number of seconds accounted seconds for by this function and those listed above it.
self the number of seconds accounted for by this seconds function alone. This is the major sort for this listing.
calls the number of times this function was invoked, if this function is profiled, else blank. self the average number of milliseconds spent in this ms/call function per call, if this function is profiled, else blank.
total the average number of milliseconds spent in this ms/call function and its descendents per call, if this function is profiled, else blank.
name the name of the function. This is the minor sort for this listing. The index shows the location of the function in the gprof listing. If the index is in parenthesis it shows where it would appear in the gprof listing if it were to be printed.
Call graph (explanation follows)
granularity: each sample hit covers 4 byte(s) no time propagated
index % time self children called name 0.00 0.00 100/100 tt [3] [1] 0.0 0.00 0.00 100 aa [1] ----------------------------------------------- 0.00 0.00 100/100 tt [3] [2] 0.0 0.00 0.00 100 bb [2] ----------------------------------------------- 0.00 0.00 100/100 main [9] [3] 0.0 0.00 0.00 100 tt [3] 0.00 0.00 100/100 aa [1] 0.00 0.00 100/100 bb [2] -----------------------------------------------
This table describes the call tree of the program, and was sorted by the total amount of time spent in each function and its children.
Each entry in this table consists of several lines. The line with the index number at the left hand margin lists the current function. The lines above it list the functions that called this function, and the lines below it list the functions this one called. This line lists: index A unique number given to each element of the table. Index numbers are sorted numerically. The index number is printed next to every function name so it is easier to look up where the function in the table.
% time This is the percentage of the `total' time that was spent in this function and its children. Note that due to different viewpoints, functions excluded by options, etc, these numbers will NOT add up to 100%.
self This is the total amount of time spent in this function.
children This is the total amount of time propagated into this function by its children.
called This is the number of times the function was called. If the function called itself recursively, the number only includes non-recursive calls, and is followed by a `+' and the number of recursive calls.
name The name of the current function. The index number is printed after it. If the function is a member of a cycle, the cycle number is printed between the function's name and the index number.
For the function's parents, the fields have the following meanings:
self This is the amount of time that was propagated directly from the function into this parent.
children This is the amount of time that was propagated from the function's children into this parent.
called This is the number of times this parent called the function `/' the total number of times the function was called. Recursive calls to the function are not included in the number after the `/'.
name This is the name of the parent. The parent's index number is printed after it. If the parent is a member of a cycle, the cycle number is printed between the name and the index number.
If the parents of the function cannot be determined, the word `<spontaneous>' is printed in the `name' field, and all the other fields are blank.
For the function's children, the fields have the following meanings:
self This is the amount of time that was propagated directly from the child into the function.
children This is the amount of time that was propagated from the child's children to the function.
called This is the number of times the function called this child `/' the total number of times the child was called. Recursive calls by the child are not listed in the number after the `/'.
name This is the name of the child. The child's index number is printed after it. If the child is a member of a cycle, the cycle number is printed between the name and the index number.
If there are any cycles (circles) in the call graph, there is an entry for the cycle-as-a-whole. This entry shows who called the cycle (as parents) and the members of the cycle (as children.) The `+' recursive calls entry shows the number of function calls that were internal to the cycle, and the calls entry for each member shows, for that member, how many times it was called from other members of the cycle.
Index by function name
[1] aa [2] bb [3] tt
#include <stdio.h>
void bb()
{
int a = 0;
for(a = 0 ; a < 10000 ; a++) ;
}
void aa()
{
int a = 0;
for(a = 0 ; a < 10000 ; a++) ;
}
gcov 는 사용하지 않는 함수를 찾는데 유용한 유틸리티 이다.
이녀석을 사용하기 위해서는 컴파일시 -fprofile-arcs -ftest-coverage 두개의 옵션을 줘야 하는데
gcc 문서를 보니 아래와 같이 --coverage 하나만 주어도 무방할 것으로 보인다.(2010.01.24 추가 : --coverage만 해도 된다)
위의 옵션을 주고 컴파일을 하면, [파일명.gcno] 라는 파일이 생성되고,
파일을 실행하면 [파일명.gcda] 라는 파일이 생성된다. gcov [소스파일] 을 입력하면 분석을 한다.
-fprofile-arcs
Add code so that program flow arcs are instrumented. During execution
the program records how many times each branch and call is executed and
how many times it is taken or returns. When the compiled program exits
it saves this data to a file called auxname.gcda for each source file.
The data may be used for profile-directed optimizations
(-fbranch-probabilities), or for test coverage analysis
(-ftest-coverage). Each object file's auxname is generated from the
name of the output file, if explicitly specified and it is not the
final executable, otherwise it is the basename of the source file. In
both cases any suffix is removed (e.g. foo.gcda for input file
dir/foo.c, or dir/foo.gcda for output file specified as -o dir/foo.o).
--coverage
This option is used to compile and link code instrumented for coverage analysis. The option is a synonym for -fprofile-arcs -ftest-coverage (when compiling) and -lgcov (when linking). See the documentation for those options for more details.
-ftest-coverage
Produce a notes file that the gcov code-coverage utility can use to
show program coverage. Each source file's note file is called
auxname.gcno. Refer to the -fprofile-arcs option above for a
description of auxname and instructions on how to generate test
coverage data. Coverage data will match the source files more closely,
if you do not optimize.
프로파일링은 어떤 함수가 몇번이나 불려지고(call), 누가 이 함수를 부르는지(call tree)
그리고 어떤 함수가 실행하는데 오래걸리는지를 분석하는 방법이다.
일반적으로 -pg 옵션을 주고 컴파일 한뒤, 한번 실행하면 프로파일링 파일이 생성된다.(정상종료 되어야 생성됨)
프로그램 실행이후에는 gmon.out 파일이 생성되고, 이 파일을 이용하여 분석한다.
-p
Generate extra code to write profile information suitable for the analysis program prof. You must use this option when compiling the source files you want data about, and you must also use it when linking.
-pg
Generate extra code to write profile information suitable for the analysis program gprof. You must use this option when compiling the source files you want data about, and you must also use it when linking.
우여곡절끝에 VLC를 컴파일 해서 samr / H.263 코덱으로 접속을 해도 에러는 나지 않도록 했는데..
RTSP 10초 timeout으로 플레이 까지는 하지 못한다.
도대체 VLC로 유튜브 플레이한 사람은.. 용자인가 -ㅁ-?
./configure --help
Input plugins:
--with-live555-tree=PATH live.com tree for static linking
--with-dv-raw1394=PATH libraw1394 headers and libraries
--with-dv-raw1394=PATH libraw1394 tree for static linking
--with-dv-avc1394=PATH libavc1394 headers and libraries
--with-dv-avc1394=PATH libavc1394 tree for static linking
--with-dvdread=PATH libdvdread headers and libraries
--with-dvdread-tree=PATH libdvdread tree for static linking
--with-dvdnav-config-path=PATH dvdnav-config path (default search in \$PATH)
--with-opencv-tree=PATH opencv tree for linking
--with-dvbpsi=PATH libdvbpsi headers and libraries
--with-dvbpsi-tree=PATH libdvbpsi tree for static linking
--with-v4l=PATH path to a v4l-enabled kernel tree
--with-v4l2=PATH path to a v4l2-enabled kernel tree
--with-videodev2=FILE Location of videodev2.h file (default /usr/include/linux/videodev2.h)
--with-dvb=PATH path to a dvb- and v4l2-enabled kernel tree
--with-ogg-tree=PATH ogg tree for static linking
--with-mod-tree=PATH mod tree for static linking
--with-gme-tree=PATH gme tree for static linking
Codec plugins:
--with-mad=PATH path to libmad
--with-mad-tree=PATH mad tree for static linking
--with-faad-tree=PATH faad tree for static linking
--with-twolame-tree=PATH twolame tree for static linking
--with-a52=PATH a52 headers and libraries
--with-a52-tree=PATH a52dec tree for static linking
--with-a52-fixed specify if liba52 has been compiled with fixed point support
--with-dca-tree=PATH libdca tree for static linking
--with-flac-tree=PATH flac tree for static linking
--with-libmpeg2-tree=PATH libmpeg2 tree for static linking
--with-vorbis-tree=PATH vorbis tree for static linking
--with-speex-tree=PATH speex tree for static linking
--with-tarkin-tree=PATH tarkin tree for static linking --with-x264-tree=PATH x264 tree for static linking
Video plugins:
--with-x use the X Window System
--with-sdl-config-path=PATH sdl-config path (default search in \$PATH)
--with-sdl-prefix=PATH path to libsdl (needed for cross-compiling),
e.g use as:
--with-sdl-prefix=/usr/local/arm/2.95.3/arm-linux/usr)
--with-qte=PATH Qt Embedded headers and libraries
--with-directx=PATH Win32 DirectX headers
--with-directfb=PATH path to DirectFB headers and libraries
--with-ggi=PATH path to libggi
--with-caca-config-path=PATH caca-config path (default search in \$PATH)
vlc의 트리구조는 다음과 같은데
vlc-1.0.4
|-- autotools
|-- bin
|-- compat
|-- doc
|-- extras
|-- include
|-- libs
|-- m4
|-- modules
|-- po
|-- projects
|-- share
|-- src
`-- test
vlc/extras 에 plugin들을 다운로드 한 다음
./configure --with-x264=tree=./extras/x264
이런식으로 설정해주면 하위까지 같이 컴파일하게 된다.
문제는, samr은 이전에 설정해 준, opencore-amr 쪽에서 알아서 samr 코덱이 들어간듯.
이건 어떻게 분리해서 넣어야 하나..
아무튼, youtube + RTSP로 검색하다보니, xHTML이 빠져서 그런거 같은 느낌이 강하게 든다..
도대체 이넘은 또 어떻게 산을 넘어가야 하나?
YouTube launched its mobile site, YouTube Mobile on 15 June 2007. It is based on xHTML and uses 3GP videos with H263/AMR codec and RTSP streaming. It is available via a web interface at m.youtube.com or via YouTube's Mobile Java Application.
