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GCC's trunk, it is necessary to improve the timings from gprof/gcc -pg.
- From: "J.C. Pizarro" <jcpiza at gmail dot com>
- To: gcc at gcc dot gnu dot org
- Date: Tue, 15 May 2007 22:32:09 +0200
- Subject: GCC's trunk, it is necessary to improve the timings from gprof/gcc -pg.
Hi developers,
For the current trunk of GCC, thinking about
the related thing of gprof and option -pg of GCC,
it's important to output correctly the data with non-fatal accuracy,
preferably 4 digits decimal instead of 2, e.g 0.0000 ms instead of 0.00 s.
It's important so that the Amdahl's Law can be applicable,
mainly to improve the gain of sequential programs.
It does not have anything to do with the software's parallelization.
http://en.wikipedia.org/wiki/Amdahl's_law
To understand, to see the A & B figure and the speedup 1 / (F + (1 - F)/N).
Seeing the graph, what happens if B1 is 0.00, B2 is 0.00, .. Bn is 0.00
because of bad accuraccy of 2 digits decimal and in seconds instead of ms?
(being B=B1+B2+..+Bn).
http://gcc.gnu.org/ml/gcc/2007-04/msg00175.html
http://gcc.gnu.org/ml/gcc/2007-04/msg00176.html
http://gcc.gnu.org/ml/gcc/2007-04/msg00177.html