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Re: Fibonacci and performance

To: alk at pobox dot com
Subject: Re: Fibonacci and performance
From: Tom Tromey <tromey at redhat dot com>
Date: 27 Apr 2001 12:27:33 -0600
Cc: java at gcc dot gnu dot org
References: <874rval8r6.fsf@creche.redhat.com> <15081.42288.250685.718037@spanky.love.edu>
Reply-To: tromey at redhat dot com

>>>>> "Tony" == Tony Kimball <alk@pobox.com> writes:

Tony> When I made the fib(x) method not to be static any more,
Tony> the time was cut roughly in half:

Ok.  But when I compare the non-static Fib.java against fib.cc I still
see a difference:

    creche. ./Fx ; echo ; ./Fj
    102334155
    Fibonacci: n = 40 took 15789 ms

    102334155
    Fibonacci: n = 40 took 21070 ms

In this case the gcj assembly output looks very different from the g++
output (before the change it was very similar).  For one thing the
assembly (both at -O2) for the function in question is almost twice as
long for gcj.

Tom

Follow-Ups:
- Re: Fibonacci and performance
  - From: Alexandre Petit-Bianco

References:
- Fibonacci and performance
  - From: Tom Tromey
- Fibonacci and performance
  - From: Tony Kimball

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