Hi, > On Thursday 16 January 2003 23:26, Quentin Mason wrote: > > Hi, > > I was wondering whether it was common knowledge or whether anyone else has > > noticed how much faster it is to compile things on MandrakePPC over an > > Intel machine ? > > For example: > > 500 Mhz 1Mb L2 Cache, 384Mb RAM Wallstreet Powerlogix G3 upgrade, g++ 2.95 > > ~3mins Dual 933 MHz Pentium 3, 1Gb RAM , > > g++ 3.2.1 2.25 Hrs > > You should try this again using the SAME compiler version on both machines. > gcc 2.95 is known to run circles around 3.x on the same machine, as 3.x had a > full API change and is now waaay slower than gcc 2.95, though it produces > faster and smaller binaries.
That has not been my experience -- I have found that g++3.2.1 is somewhat faster (and smaller memory+stackspace footprint whilst compiling) than 2.95.3. I found an older compiler on the office machines, and it did indeed take longer than 3.2.1: Dual 933Mhz P3 g++2.95.3 3.5 hrs Dual 933Mhz P3 g++3.2.1 2.25 hrs 500Mhz Wallstreet g++2.95.3 ~3mins I am compiling over NFS -- surely that cannot be the problem for such a large file and long compile time ? One of the advantages of the 3.x series is the "-Q" flag on the compiler -- it tells you exactly what template instantiation or subroutine that it is working on [watch how compiler-expensive all those #includes are -- what pre-compiled headers could do...], and spits out a time spent analysis on all the steps (including optimisation). However I do not have a g++3 for PPC [anyone have a {ppc,src}.rpm to coexist with system compiler ?] to compare where the time is spent. Q.