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From "Xiao-Feng Li" <xiaofeng...@gmail.com>
Subject Re: [drlvm] log4cxx vs custom logger Re: [general] icu or apr-iconv, which coding library is better?
Date Mon, 14 Apr 2008 13:52:10 GMT
I personally support to have a custom logger. Maybe it is just
personal taste that, when I write SW, I always try to keep the code
limited to what is needed, and I don't want the SW to have too many
unnecessary external dependences. And, my experience with log4cxx was
not very pleasant. :(

Thanks,
xiaofeng

On Mon, Apr 14, 2008 at 6:49 PM, Alexey Varlamov
<alexey.v.varlamov@gmail.com> wrote:
> Folks,
>
>  I suggest we avoid subject screening and discuss the main issue
>  purposefully: what functionality do we need from VM logging and
>  whether it worths to replace log4cxx with custom lightweight impl (see
>  HARMONY-5692).
>  Main points:
>  - log4cxx is very powerful and highly customizable facility, it
>  provides control over log output at arbitrary granularity (literally,
>  any category with any logging level may be independently output to
>  different (mulltiply) destinations (file, socket, DB, etc) in
>  arbitrary format), supports logs rotations, config files etc.
>  - log4cxx is relatively costly: draws extra external dependencies,
>  increases binary weight of VM (how much for _release_ build, BTW?),
>  needs certain integration level.
>  - most of the log4cxx features and flexibility are not really used at
>  the moment (yet might appear invaluable for remote debugging or
>  maintenance).
>  - few features of Invocation API (vfprintf/exit/abort hooks) are not
>  supported in current log4cxx integration (should not be too hard to
>  add).
>  - the small logger, suggested by Alexei F, gives those features of
>  Invocation API for free and reduces dependency constraints for potrlib
>  (I think performance wins are negligible).
>
>  So, do we want to exchange feature-rich but heavy LOG4CXX for small
>  and compatible logger (and more freedom to choose a VM portlib)?
>
>  I personally have no principal objections for the suggested
>  replacement, just want to ensure the simple logger is functional
>  enough and supports most important usecases (I listed them in the
>  JIRA).
>
>  Regards,
>  Alexey
>
>
>  2008/4/14, Alexei Fedotov <alexei.fedotov@gmail.com>:
>  > Hello Nathan,
>  > Thanks for your tough questions.
>  > 1.
>  > I'm sorry for using "red herring". I honestly believe that having two
>  > charset coding libraries is overkill and a good reason to throw one of
>  > them away.
>  >
>  > 2.
>  > Here is a JNI specification [1]. Please, check a table below
>  > JNI_CreateJavaVM description. It describes how VM logging is
>  > initialized. This was not implemented in DRLVM, and is implemented in
>  > [2].
>  >
>  > 3.
>  > A big chunk of removed functionality is logging into separate files.
>  > To my perception, this is not a frequent use case. The original reason
>  > why original DRLVM engineers attached log4cxx to my original C/C++
>  > DRLVM logger was our attempt to achieve "Apache synergy".
>  >
>  > 4.
>  > You asked for an anecdotal proof of the fact why smaller executables
>  > may run faster. I have just invented one: smaller executables better
>  > fit into a processor cache, produce less cache misses and hence
>  > decrease a bus load. For a particular case this should be measured,
>  > and I don't have solid data yet.
>  >
>  > 5.
>  > There is one more argument which actually forced me to start thinking
>  > into this direction: my shmmap component (a hybrid of shm and mmap)
>  > was originally developed as a part of aprutil (because it is based on
>  > apr_shm and apr_mmap). We already have four porting libraries: port,
>  > portlib, apr and aprutil in Harmony. Removing one which is not tightly
>  > coupled with other parts make it easier for people like me to decide
>  > where it is natural to place our hand-made components.
>  >
>  > More questions? Suggestions?
>  >
>  > [1] http://java.sun.com/j2se/1.5.0/docs/guide/jni/spec/invocation.html
>  > [2] https://issues.apache.org/jira/browse/HARMONY-5692
>  >
>  >
>  > On Mon, Apr 14, 2008 at 6:39 AM, Nathan Beyer <nbeyer@gmail.com> wrote:
>  > > On Sun, Apr 13, 2008 at 4:17 AM, Alexei Fedotov
>  > >
>  > > <alexei.fedotov@gmail.com> wrote:
>  > >
>  > > > Hello Nathan,
>  > >  >  Thanks for questions.
>  > >  >
>  > >  >  There are many other places where charset (en/de)coders are used, but
>  > >  >  we use icu4c there.
>  > >
>  > >  I know, but your original post made it sound like this was the big
>  > >  reason for accepting this patch, but charset codec usage was a red
>  > >  herring - I really don't like it when people use such tactics. Focus
>  > >  on the real issue, please.
>  > >
>  > >
>  > >
>  > >  > HARMONY-5692 is a replacement of log4cxx with
>  > >  >  custom logger and removing dependent aprutil and apr-iconv which are
>  > >  >  not used any longer after this replacement.
>  > >  >    * The replacement decreases
>  > >  >  windows_x86_msvc_debug/deploy/jdk/jre/bin/default/harmonyvm.dll size
>  > >  >  from 4079616 to 2961408. This would probably improve a startup time.
>  > >
>  > >  Any proof, even anecdotal to this claim?
>  > >
>  > >
>  > >  >    * The custom logger requires less lines of code than a log4cxx
>  > >  >  wrapper, hence, is easier to maintain.
>  > >  >    * By specification VM logging should be done using provided
>  > >  >  vfprintf. C++ logger adds two layers of conversion. vfprintf layer
wan
>  > >  >  not implemented, and implementing it would increase a number of
>  > >  >  wrappers for log4cxx.
>  > >
>  > >  Can you point to this bit of the specification? I don't understand the
>  > >  last bit of what you're claiming. There's a wrapper that doesn't
>  > >  exist, but needs to?
>  > >
>  > >
>  > >  >
>  > >  >  Please, let me know if these arguments are enough for log4cxx being
removed.
>  > >
>  > >  No, they aren't for me. The original DRLVM engineers used log4xx for a
>  > >  reason, what functionality are we giving up?
>  > >
>  > >
>  > >
>  > >  >
>  > >  >  Note, apr itself remains, and it is pretty good piece of code to my
>  > >  >  perception. I do not intend to invent pools or OS call wrappers. We
>  > >  >  throw away the staff guys from apr does not allow to put into their
>  > >  >  main module. :-)
>  > >  >  Thanks.
>  > >  >
>  > >  >
>  > >  >
>  > >  >
>  > >  >  On Sun, Apr 13, 2008 at 12:30 AM, Nathan Beyer <nbeyer@gmail.com>
wrote:
>  > >  >  > Huh? This post doesn't sound like anything in HARMONY-5692. We
need
>  > >  >  >  clear somethings up first.
>  > >  >  >
>  > >  >  >  1. apr-iconv is in the build as a dependency of log4cxx
>  > >  >  >  2. there is no use of apr-iconv for charset encoding/decoding
>  > >  >  >  3. HARMONY-5692, AFAIU is replacement of log4cxx with custom
logger
>  > >  >  >  implementation to reduce the build time
>  > >  >  >
>  > >  >  >  What's the value of replacing log4cxx with a custom logger? Reducing
>  > >  >  >  the build time isn't enough for me - there have to be other ways
to
>  > >  >  >  accomplish that without sub-system replacement.
>  > >  >  >
>  > >  >  >  -Nathan
>  > >  >  >
>  > >  >  >
>  > >  >  >
>  > >  >  >  On Fri, Apr 11, 2008 at 10:37 PM, Alexei Fedotov
>  > >  >  >  <alexei.fedotov@gmail.com> wrote:
>  > >  >  >  > Hello,
>  > >  >  >  >
>  > >  >  >  >  One may notice that both icu and apr-iconv are currently
used to build
>  > >  >  >  >  Harmony HDK. Both libraries address charset encoding and
decoding.
>  > >  >  >  >  Should we keep both of them or try to use the only one?
>  > >  >  >  >
>  > >  >  >  >  HARMONY-5692 [1] contains one possible "compilable" answer
to this
>  > >  >  >  >  question and related reasoning. Alexey Varlamov and Tim
suggested
>  > >  >  >  >  discussing the matters on dev@ list, so I created this
thread on the
>  > >  >  >  >  subject. You are welcome to share your opinion about the
libraries
>  > >  >  >  >  Harmony depends on, the patch from [2], my arguments defending
the
>  > >  >  >  >  patch, and further directions here.
>  > >  >  >  >
>  > >  >  >  >  --
>  > >  >  >  >  With best regards,
>  > >  >  >  >  Alexei
>  > >  >  >  >
>  > >  >  >  >  [1] https://issues.apache.org/jira/browse/HARMONY-5692
>  > >  >  >  >
>  > >  >  >
>  > >  >
>  > >  >
>  > >  >
>  > >  >  --
>  > >  >  With best regards,
>  > >  >  Alexei
>  > >  >
>  > >
>  >
>  >
>  >
>  > --
>  > With best regards,
>  > Alexei
>  >
>



-- 
http://xiao-feng.blogspot.com

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