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From Adam Kocoloski <kocol...@apache.org>
Subject chunkify profiling (was Re: Patch to couch_btree:chunkify)
Date Wed, 13 May 2009 19:33:07 GMT
Sorry for the delay on this front.  I ran hovercraft:lightning 20  
times each with and without Paul's patch.  Each run inserted 2k docs  
in batches of 1000.  Here are two plots showing the effect of the patch:

http://dl.getdropbox.com/u/237885/insert_rate.png
http://dl.getdropbox.com/u/237885/chunkify_fraction.png

The first plot histograms the insert rate for the two scenarios*.  I  
don't really see much of a difference.  The second plot uses fprof to  
plot the fraction of time the couch_db_updater process spent in  
chunkify and any functions called by chunkify.  For those familiar  
with fprof, it's the ratio of ACC for couch_btree:chunkify/2 divided  
by OWN for the updater pid.  If fprof is to be believed, the trunk  
code is almost 2x faster.

Adam

* the reason the insert rate is so low is because fprof is running.   
Turning off the profiler speeds things up by an order of magnitude, in  
accord with the numbers Chris has posted.

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