On Wed, May 04, 2005 at 09:00:05AM -0700, Joe Buck wrote: > On Wed, May 04, 2005 at 06:41:59AM -0700, H. J. Lu wrote: > > On Wed, May 04, 2005 at 11:23:20AM +0100, Andrew Haley wrote: > > > Joe Buck writes: > > > > Richard Henderson showed that the libjava build spends 2/3 of its time > > > > in libtool, and that his hand-hacked (but not portable) modification to > > > > invoke the appropriate binutils commands directly gave a huge speedup. > > > > > > Yes, but please bear in mind that this *only* happens when you have a > > > machine with huge RAM. For other people with small RAM, the link > > > itself is an important factor. Also, other people have found that the > > > libtool script consumes a smaller part of total execution time: rth's > > > measurements are at one extreme of the scale. > > > > We have been working on linker speed. If you have a number to show > > that the GNU linker is very slow on certain things, I will take a > > look. > > I'm glad you're looking at speeding up the linker. Please make sure to > look at memory consumption as well, since performance falls off a cliff > once the working set exceeds physical memory. A good test would be to > bootstrap gcc on a machine with 256M, or that is artificially limited to > 256M (I seem to recall that you can tell a Linux kernel you have only a > given amount of memory).
Given the current hardware, I would say 512MB is a reasonable number. If I need to more than 256M to get 5% speed up, I will take it. BTW, for gcc 4.0, I got 11687.92user 2089.89system 2:11:43elapsed 174%CPU (0avgtext+0avgdata 0maxresident)k for bootstrap 9710.54user 2628.79system 1:52:03elapsed 183%CPU (0avgtext+0avgdata 0maxresident)k for "make check" on a dual P3 550MHz with 512MB with everything except for Ada. H.J.
