[CMake] [Fwd: Re: Why does dependency scanning in version 2.6 seem so slow?]

[Jose Luis Blanco]

These are my results: All the details go below, but in two computers, both
with cmake 2.6.0 (from the Ubuntu repositories), it takes ~ 50sec vs. 19sec
to recompile when only one file changes... and the longest delay happens in
the better PC, though the CPU's are very similar in speeds. Both cases are
local file systems (through ntfs, but the same in both cases).

In addition, I started with a fresh CMAKE_BINARY_DIR directory in both
cases.

Please, let me know if I can do any more logging.

Regards,
JL


=============================
PC #1
DESKTOP PC, QuadCore 2.4Ghz:
=============================

==> touch'ing just one .cpp file in the project, the "time make VERBOSE=1"
gives:   49.882s

cd /home/jlblanco/code/mrpt-release && /usr/local/bin/cmake -E cmake_depends
"Unix Makefiles" /home/jlblanco/code/mrpt-src
/home/jlblanco/code/mrpt-src/src/core /home/jlblanco/code/mrpt-release
/home/jlblanco/code/mrpt-release/src/core
/home/jlblanco/code/mrpt-release/src/core/CMakeFiles/mrpt-core.dir/DependInfo.cmake
--color=

Most of the time goes in these 3 steps:

Dependee "/home/jlblanco/code/mrpt-src/src/core/math/CMatrix.cpp" is newer
than depender "src/core/CMakeFiles/mrpt-core.dir/math/CMatrix.o".
Clearing dependencies in
"/home/jlblanco/code/mrpt-release/src/core/CMakeFiles/mrpt-core.dir/depend.make".

Clearing dependencies in
"/home/jlblanco/code/mrpt-release/src/core/CMakeFiles/mrpt-core.dir/depend.make".

Scanning dependencies of target mrpt-core  <<<< Longest task

real    0m49.882s
user    0m5.424s
sys    0m7.064s


==> without touching (just realizing there's nothing to do):  12.89s

Most of the time goes in:

cd /home/jlblanco/code/mrpt-release && /usr/local/bin/cmake -E cmake_depends
"Unix Makefiles" /home/jlblanco/code/mrpt-src
/home/jlblanco/code/mrpt-src/src/core /home/jlblanco/code/mrpt-release
/home/jlblanco/code/mrpt-release/src/core
/home/jlblanco/code/mrpt-release/src/core/CMakeFiles/mrpt-core.dir/DependInfo.cmake
--color=

real    0m12.896s
user    0m1.384s
sys    0m1.560s


=============================
PC # 2
LAPTOP PC, DualCore 2.0Ghz:
=============================

==> touch'ing just one .cpp file in the project, the "time make VERBOSE=1"
gives:   18.78s

Most of the tiime goes to:

cd /home/jlblanco/code/mrpt-release && /usr/bin/cmake -E cmake_depends "Unix
Makefiles" /home/jlblanco/code/mrpt-src
/home/jlblanco/code/mrpt-src/src/core /home/jlblanco/code/mrpt-release
/home/jlblanco/code/mrpt-release/src/core
/home/jlblanco/code/mrpt-release/src/core/CMakeFiles/mrpt-core.dir/DependInfo.cmake
--color=
Dependee "/home/jlblanco/code/mrpt-src/src/core/utils/CMRPTImage.cpp" is
newer than depender "src/core/CMakeFiles/mrpt-core.dir/utils/CMRPTImage.o".
Clearing dependencies in
"/home/jlblanco/code/mrpt-release/src/core/CMakeFiles/mrpt-core.dir/depend.make".
Scanning dependencies of target mrpt-core

real    0m18.788s
user    0m7.456s
sys    0m4.552s



==> without touching (just realizing there's nothing to do):  2.23s

real    0m2.234s
user    0m1.468s
sys    0m0.528s






On Thu, Dec 4, 2008 at 4:02 AM, Bill Hoffman <bill.hoffman at kitware.com>wrote:

> Jose Luis Blanco wrote:
>
>> If this helps anyone, I'm working on a large project using CMake and in
>> two different computers, both with the same version of Ubuntu and cmake, it
>> is *REALLY SLOW* in only one of them while scanning dependencies, but it's
>> not in the other laptop.  (The "slow" dep. scanning is ~1 min. too)
>>
>> I'd be happy to help debugging this, because it's really annoying :-(
>>
>>  I wonder if it is hitting a network mount disk or something like that...
>  Are the same versions of cmake identical binaries?
>
> -Bill
>



-- 

___________________________________________________________

Jose-Luis Blanco-Claraco      Phone: +34 952 132848
Dpto. Ingenieria de Sistemas y Automatica
E.T.S.I. Telecomunicacion       Fax: +34 952 133361
Universidad de Malaga
Campus Universitario de Teatinos
29071 Malaga, Spain

http://www.isa.uma.es/jlblanco
___________________________________________________________
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