On Jan 23, 2011, at 22:45 , Angelo Dell'Aera wrote:
> I really think such verbose logging should be turned off 
> by default because it is quite useless to the end user and produces huge
> amounts of logs which are useless as well.
> 
> Cheers,
> 


My 2 cents to this is that responsiveness and performance of an application has 
turned out to be severely impacted even by console output, disk output of the 
same data being actually faster. Various tests have consistently shown that 
being 'distracted' for synchronous write() actually costs noticeable amounts of 
time.

For example, even a simple extraction of linux-2.6.38-rc2.tar.bz2 with and 
without -v can tell:

time tar -xvjf linux-2.6.38-rc2.tar.bz2 (console output to a terminal emulator):

real            4m38.434s
user    1m30.148s
sys             0m40.721

time tar -xvjf linux-2.6.38-rc2.tar.bz2 > filelist.txt:

real            3m5.595s (actually faster than console!)
user    1m27.162s
sys             0m35.854s

time tar -xvjf linux-2.6.38-rc2.tar.bz2 > /dev/null:

real            2m57.909s (36% faster, now we're talking business)
user    1m26.851s
sys             0m34.696s

(Non-verbose tar -xjf does not make much difference from piping into /dev/null 
at least on Mac OS X, but  probably its being written in C and going through 
less levels of indirection between if(verbose) check and actual output have 
contributed to that; turning Twisted's logging off completely invariably gave 
tremendous performance boosts.)

Maybe I'm missing something here, but that's what my experience on several 
projects said.

(Here was going to be the part where I would actually propose some sort of 
solution but it turned out to be so stupid on the second sight that I decided 
to scrap it until I work out the details.)


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