[Twisted-Python] Names DNS Client too chatty

Jarosław Fedewicz jaroslaw.fedewicz at gmail.com
Sun Jan 23 17:11:56 MST 2011


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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